67 International Symposium on Crop Protection

i

ABSTRACTS

67th International Symposium on Crop Protection

May 19, 2015 Ghent Belgium

GHENT UNIVERSITY Faculty of Bioscience Engineering Coupure links 653 BE-9000 Gent (Belgium)

ii

PATRONS

iii

CONTENT

Plenary

1

Special Session – Emerging pests and diseases

7

Session 1 – Nematology

15

Session 2 – Agricultural Entomology and Acarology

27

Session 3 – Herbology

39

Session 4 – Formulation and Application Technology

47

Session 5 – Pesticide Application and Pesticide Residues

55

Session 6 – Phytopathology I

63

Session 7 – Phytopathology II

73

Posters Special Session – Emerging pests and diseases

85

Nematology

91

Agricultural Entomology and Acarology

103

Herbology

145

Pesticide Residues, Toxicology and Ecotoxicology

151

Phytopathology

169

iv

1

Plenary

2

3

Plenary 09:30

EXPLOITING MODEL GENOMES: USING FORWARD AND REVERSE GENETICS TO ELUCIDATE FUNCTIONAL HOST – PARASITE INTERACTIONS IN PLANT-PARASITIC NEMATODES K.G. DAVIES School of Life and Medical Sciences, University of Hertfordshire Hatfield, Hertfordshire, AL10 9AB, UK

Forward genetics is the process whereby from an observable phenotype the genes responsible for that phenotype are identified. Reverse genetics is in the opposite direction; it is a process whereby a known gene is disrupted to identify its phenotype. Traditional genetics was built on forward genetics whereby mutants were generated (either by radiation or chemicals) and breeding experiments are undertaken to “map” these genes; classically mutant phenotypes were often observed many years before the genes were mapped. Reverse genetics, the opposite of forward genetics, has grown substantially following the advent of DNA sequencing. The Pasteuria group of bacterial invertebrate hyper parasites are being used to study co-evolutionary relationships the understanding of which will be key in its use as a control agent of phyto nematodes. Although the genomes of their hosts have been successfully sequenced the genomes of Pasteuria spp. have proved problematic and currently there is no published genome. This is partly due to their obligate nature and therefore the inability to get pure strain specific DNA. I will clarify this problem and explore the possibilities of how to exploit fragmented and partially sequenced genomes using this nematode – bacterial interaction as a case study. Indeed, to an extent, this is the normal position of the crop protection scientists who has to deal with field populations of a pathogen, pest or weed, the genomes of which will only approximate to the isolate that has been sequenced if it has been sequenced at all.

4

Plenary 10:00

SOIL ECOLOGY AS KEY TO SUSTAINABLE CROP PRODUCTION G.B. DE DEYN Dept. Soil Quality, Wageningen University, The Netherlands

Sustainable production of food, feed and fiber warrants sustainable soil management and crop protection. The tools available to achieve this are both in the realm of the plants and of the soil, with a key role for plant-soil interactions. At the plant level we have vast knowledge of variation within plant species with respect to pests and diseases, based on which we can breed for resistance. However, given that systems evolve this resistance is bound to be temporarily hence also other strategies are needed. Here I plea for an integrative approach for sustainable production using ecological principles. Ecology, the study of how organisms interact with their environment, teaches us that diversity promotes productivity and yield stability. These effects are thought to be governed through resource use complementarity and reduced build-up of pests and diseases both above- and belowground. In recent years especially the role of soil biotic interactions has revealed new insights in how plant diversity and productivity are related to soil diversity and the functions they govern. In this presentation I will show how working on biocontrol of root-feeding nematodes led me to appreciate their role in ecosystems and to pursuit unravelling how plant-soil feedbacks are generated and can be used to optimize sustainable crop productivity. Key words: ecological intensification, plant-soil feedback, above-belowground interactions, plant traits and trade-offs

5

Plenary 15:00

THE LACK OF KNOWLEDGE OF CONSUMERS TOWARDS THE RESEARCH, THE NEED AND THE BENEFIT OF CROP PROTECTION (CHEMICAL, ORGANIC, INTEGRATED SOLUTIONS) C. HARRIS Exponent International Limited The Lenz, Hornbeam Business Park, Harrogate, North Yorkshire, HG2 8RE, UK

Crop protection products contribute to a sustainable supply of food to most areas of the world. However, when European consumers are asked for their opinions on the use of these compounds, the common response is that they damage the environment, cause health effects and have questionable benefits. Over many years of monitoring consumer opinion by governments, health agencies, retailers and research institutions, these opinions have not changed and pesticides and their residues remain identified in the top three concerns for consumers. However, crop protection products are highly regulated with stringent requirements which need to be met before they can be used commercially. This paper reviews consumer opinions and attitudes to crop protection products from various surveys worldwide in order to explore the continuing differences between the level of research and regulation undertaken and the reported negative views held of these products.

6

7

Special Session EMERGING PESTS AND DISEASES

8

9

Special session Emerging pests and diseases 11:00

VECTOR REQUIRED; THE CASE OF BURSAPHELENCHUS XYLOPHILUS AND MONOCHAMUS SPP. FOR BELGIUM N. BERKVENS1, N. VIAENE1, L. WAEYENBERGE1, N. DE SUTTER1, C. BOONE², J-C. GRÉGOIRE², D. MICHELANTE³ and H. CASTEELS1 1

ILVO, Plant – Crop Protection Burg. van Gansberghelaan 96, BE-9820 Merelbeke, Belgium 2 Université Libre de Bruxelles, LUBIES Avenue FD Roosevelt 50, BE-1050 Brussels, Belgium 3 FASFC, Food Safety Centre Kruidtuinlaan 55, BE-1000 Brussels, Belgium

The pinewood nematode (PWN) Bursaphelenchus xylophilus is a quarantine nematode which is currently absent in Belgium. Its status is based on phytosanitary controls of imported wood products and annual national surveys by the Belgian Federal Agency for the Safety of the Food Chain (FASFC). These measures have been implemented since 2000 following the first report of the PWN in southern Europe in 1999. It is unclear if and how the PWN will spread and/or establish throughout Belgium if it is introduced in the future, as there is no knowledge concerning the presence of its vectors, longhorn beetles of the genus Monochamus. It is essential to identify Monochamus species occurring in Belgium and map their geographic distribution and densities in order to develop an eradication strategy for possible PWN contaminations. We are gathering this information by stimulating public participation in the search for these longhorn beetles and by surveying the Belgian pine forests using a network of attractant traps. During the first two years of our 3-year project only a few adults of M. galloprovincialis and M. sartor were found at 6 locations in Flanders, and none in the Wallonia and Brussels regions. To increase the efficiency of the monitoring system, trap-attractant combinations were evaluated and the application of ‘wet catching’ was examined. Cross-vane traps containing 2undecyloxy-1-ethanol (monochamol), ipsenol, 2-methyl-3-buten-1-ol and alpha-pinene resulted in higher catches of longhorns than intercept traps excluding alpha-pinene. The effect of monoethylene glycol (MEG), a preservative used in wet catching, on the diagnostic features of PWN was evaluated. While morphological features deteriorated with increasing concentrations of MEG and with time, molecular detection of the nematodes was not affected. Further experiments and field monitoring during the final year of the project (2015) should indicate if the observed longhorn individuals are endemic or imported. The information gathered will result in designing a monitoring program based on risks of PWN spread linked to the density of the vector population and action programs for Belgium. Key words: Bursaphelenchus xylophilus, Monochamus spp., vector, phytosanitary, risk

10


A SEASON-LONG IPM STRATEGY FOR TUTA ABSOLUTA IN BELGIAN GREENHOUSES E. BERCKMOES1, H. CASTEELS2, R. DE VIS1, P. DE CLERCQ3, R. MOERKENS4, L. TIRRY1, V. VAN DAMME2,3 and L. WITTEMANS1 1

3

Research Station for Vegetable Production Duffelsesteenweg 101, BE-2860 Sint-Katelijne-Waver, Belgium 2 Institute for Agricultural and Fisheries Research (ILVO) Burgemeester van Gansberghelaan 96, BE-9820 Merelbeke, Belgium Ghent University, Faculty of Bioscience Engineering, Department of Crop Protection Laboratory of Agrozoology Coupure Links 653, BE-9000 Ghent, Belgium 4 Research Centre Hoogstraten Voort 71, BE-2328 Meerle, Belgium

The tomato leafminer or Tuta absoluta Meyrick is a key tomato pest originating from South America. It was detected for the first time in Belgium in 2009. At the end of 2010 the tomato leafminer had already spread in the main tomato production areas in Belgium and had caused important damage. A research project was started in 2011 to develop an IPM control strategy against this tomato pest. The strategy is mainly based on the use of the predatory bug Macrolophus pygmaeus as this is the only natural enemy of T. absoluta that is allowed in Belgium. Because of the slow establishment of M. pygmaeus a lot of research and monitoring was focused on its population build up. We found that it is necessary to release this beneficial as soon as possible after transplanting. It is recommended to provide additional food sources as the commercially available Ephestia and Artemia during 6 to 8 weeks. We also found that with one properly performed release the same population build up can be obtained as with two releases. Monitoring of the pest organism T. absoluta as well as the beneficial M. pygmaeus is essential to evaluate the balance between the two populations and to take further actions if needed. Therefore every 2 to 3 weeks 90 leaves are assessed for the presence of T. absoluta and all stages of M. pygmaeus. When present, also other preys of the generalist predator M. pygmaeus need to be monitored as their presence could influence the predation rate of M. pygmaeus on T. absoluta. If chemical intervention is needed, side effects towards M. pygmaeus must be considered, in particular during the establishment period of M. pygmaeus. The present stages of T. absoluta are also important to select the right timing and active ingredient of the chemical product. Key words: Tuta absoluta, IPM, Macrolophus pygmaeus

11


TUTA ABSOLUTA (LEPIDOPTERA: GELECHIIDAE) DEVELOPMENT ON WILD AND CULTIVATED PLANT SPECIES T. BAWIN, D. DUJEU, M. FAGAN, L. DE BACKER, F. FRANCIS and F.J. VERHEGGEN Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liege 2 Passage des Déportés, BE-5030 Gembloux, Belgium

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important cultivated solanaceous crop plants, including tomatoes and potatoes. Little is known about the ability of this micro Lepidoptera to encounter and develop on alternative wild and agricultural plant species. These plants could provide refuges and have to be identified for more efficient integrated management strategies. In the present study, we assessed under laboratory conditions the ability of T. absoluta to develop on such plant species referred as potential hosts in the literature, including Solanaceae, Chenopodiaceae, Convolvulaceae, Fabaceae, and Malvaceae. For each plant species, fitness tests were performed in Petri dishes by isolating single individuals with excised leaf. We found that Solanum species allowed higher larval survivability and shorter development time (from egg to adult emergency) compared to the other plants. Non-solanaceous plants were not able to sustain T. absoluta larvae. Two choice behavioural assays performed in flying tunnels revealed that adult distribution and female oviposition did not differ between Solanum species, which were preferred to other tested solanaceous plants. These results appeared to be consistent with survival rates and development times. Because larval survivability depends on the female’s oviposition choice, the hypothesis that host plant choice is influenced by plant volatile organic compounds has to be tested. Volatile organic compounds released by solanaceous plants were trapped using a dynamic collection system, and analyzed by GC-MS. Solanum volatile profiles showed similarities, and were presenting quantitative and qualitative differences with the other tested solanaceous plants, providing some explanations in the observed behavioural discrimination. Further electrophysiological and behavioural assays are required to confirm the effect of specific chemicals on the choice of the oviposition site in T. absoluta. It can be concluded that Solanum species are the more suitable hosts for T. absoluta development. Other solanaceous plant species could be opportunistically colonized with little incidence but care should be taken in these results as genetic variability in insects and plants, as well as plant physiological state, might have an impact on the pest survivability. Key words: Tuta absoluta; alternative host plant; potato; black nightshade; plant volatile organic compound

12


DETECTION OF XYLELLA FASTIDIOSA ON ORNAMENTAL COFFEE PLANTS M. BERGSMA-VLAMI, J.L.J. VAN DE BILT, N.N.A. TJOU-TAM-SIN, B.T.L.H. VAN DE VOSSENBERG and M. WESTENBERG National Plant Protection Organization (NPPO) P.O. Box. 9102, NL-6700 HC Wageningen, the Netherlands

Xylella fastidiosa is a xylem-limited, Gram-negative bacterium restricted until recently to the Americas. It is regulated in the European Union (EU) and causes significant economic losses in many agriculturally important plants, including citrus, coffee, grape and several different tree species, perennial crops and landscape plants. Outside the American continent was Xylella fastidiosa previously reported in Taiwan and Iran. Four pathogenic subspecies of the bacterium have been described: Xylella fastidiosa subsp. fastidiosa, X. fastidiosa subsp. multiplex, X. fastidiosa subsp. pauca and X. fastidiosa subsp. sandyi. Xylella fastidiosa is exclusively transmitted by xylem-sap feeding insects. It causes variegated chlorosis on citrus, Pierce’s disease in grape, phony disease in peach, crespera in coffee and leaf scorching in many plants. Recently has Xylella fastidiosa expanded its geographic range inside the EU. At the end of 2013 was the bacterium discovered to be responsible for the Olive Quick Decline Syndrome (OQDS) of Olea europaea trees in southern Italy, where it has been spreading rapidly. As a preventive measure against the introduction of this harmful organism in the EU, emergency measures were adapted providing guidelines for the import and movement of particular host plants. Following the Commission Implementing Decision 2014/87/EU, an official survey for the presence of Xylella fastidiosa on coffee plants has been undertaken in 2014 in the Netherlands, based on import data from the past few years. Xylella fastidiosa was detected on ornamental coffee plants exhibiting a range of different symptoms from symptomless plants up to mild leaf scorching and crespera. The results of this survey will be discussed. Key words: Xylella fastidiosa, coffee, crespera, leaf scorch

13


RE-EMERGENCE OF GOSS’S BACTERIAL WILT OF CORN: PATHOGEN CHARACTERIZATION AND DETECTION J.T. TAMBONG1, R. XU1, L. PARENT1, A. BERGERON1, P. VINETTE1, M. COTT2, K. ROSE2, F. DAAYF3, L. REID1, S. BRIERE4, G. BILODEAU4, R. TROPIANO4, I.V. AGARKOVA5 and E.S.P. BROMFIELD 1

4

Agriculture and Agri-Food Canada 960 Carling Avenue, Ottawa, ON Canada K1A 0C6 2 Manitoba Corn Growers Association 38 4th Ave NE, Carman, MB R0G 0J0 3 Department of Plant science, 222 agriculture building University of Manitoba Winnipeg, MB R3T 2N2, Canada Canadian Food Inspection Agency, 3851 Fallowfield Road, Ottawa, Ontario. Canada, K2H 8P9 5 Department of Plant Pathology, University of Nebraska-Lincoln 214 Morrison Center Lincoln, NE 68583-0900

The re-emergence of the Goss’s bacterial wilt and blight of corn (Zea mays L.) caused by Clavibacter michiganensis subsp. nebraskensis (CMN) has prompted increased research activities to mitigate yield loss. During severe epidemics, losses could be as high as 50% from systemic infections of the xylem. The disease was first reported in 1969 in south central Nebraska but became sporadic after partially resistant cultivars were identified in field corn. The Goss’s wilt disease has re-emerged and spreading rapidly in major corn growing regions of USA and Canada. The re-emergence of CMN could be due to the use of hybrids selected solely for high yield potentials without a disease-resistance/tolerance component. Alternatively, it could be due to coevolution of pathogen and host. The appropriate response to the re-emergence of any plant pathogens necessitates a multidisciplinary approach. While corn breeders are re-evaluating the recent hybrid releases, it is important to investigate the population structure of the pathogen. Since C.m. subsp. nebraskensis causes systemic infections of the xylem that may be latent without visible symptoms, early detection using specific molecular methods is an essential part of any mitigation strategy. Moreover, this pathogen may invade seeds leading to potential phytosanitary regulatory challenges for export countries. We report results of a multilocus sequence analysis of 20 ribosomal proteins (rMLSA) of over 50 CMN strains isolated between 1969 to 2014, comparative genomics of C. michiganensis subspecies, and a specific TaqMan real-time PCR assay for rapid detection of the pathogen in pure cultures and infected plant parts. rMLSA grouped the strains into two major clusters while comparative genomics identified a unique gene present only in CMN but not in other Clavibacter michiganensis subspecies. The developed TaqMan real-time PCR assay targeted the 30S ribosomal subunit protein S10 (rpsJ) and a secreted cellulase gene. The specificity of the assay was confirmed using 80 bacterial strains and sensitivity of about 1 pg of DNA was achieved. In blind tests, the assay detected all artificially and field infected corn leaf samples without cross-reactions. The assay is being validated by the Canadian Food Inspection Agency for routine use in corn certification. Key words: Goss's wilt, Clavibacter, ribosomal proteins, TaqMan PCR, comparative genomics

14

15

Session 1 NEMATOLOGY

16

17

Session 1 Nematology 11:00

AGRICULTURAL WASTE AMENDMENTS IMPROVE INUNDATION TREATMENT OF SOIL CONTAMINATED WITH POTATO CYST NEMATODES (GLOBODERA ROSTOCHIENSIS) N. EBRAHIMI1,2, N. VIAENE1,3, S. FARZANEH ZARDASHTI3, J. AERTS4,5 and M. MOENS1,2 1

4

Department of Crop Protection, Institute for Agricultural and Fisheries Research Burg. Van Gansberghelaan 96, BE-9820 Merelbeke, Belgium; 2 Laboratory for Agrozoology, Ghent University Coupure links 653, BE-9000 Gent, Belgium 3 Nematology Unit, Department of Biology, Ghent University K.L. Ledeganckstraat 35, BE-9000 Ghent, Belgium Bio-analysis Research Group, Animal Sciences Unit, Institute for Agriculture and Fisheries Research Scheldeweg 68, BE-9090 Melle, Belgium 5 Laboratory of Food Analysis, Department of Bio-analysis Faculty of Pharmaceutical Sciences, Ghent University Ottergemsesteenweg 460, BE-9000 Gent, Belgium

Cysts of Globodera rostochiensis, a major constraint to potato production, are mainly distributed through soils. Waste soil, i.e. soil carried along with the harvested potato tubers from the field, can be treated by inundation, a disinfestation method creating an anaerobic condition of the soil. The anaerobiosis process can be accelerated by adding organic materials. The aims of this study were to evaluate the impact of inundation on survival of potato cyst nematodes and the effect of agricultural and industrial waste products on accelerating the anaerobiosis process. Experiments were conducted in closed 2-L containers filled with cyst-infested inundated soil. Cysts were placed in retrievable nylon mesh bags and buried in the soil. The effects of 6 treatments on cyst survival were studied over 8 weeks. Inundated containers were filled with (1) non-amended soil, (2) steamed potato peels, (3) fresh potato peels, (4) calcium sulphate, (5) a mixture of steamed potato peels and calcium sulphate and (6) leek. Non-amended, non-inundated soil in (7) closed and (8) open containers were included as controls. The viability of the cyst content was evaluated weekly by visual assessment and a trehalose-based method. To examine the infectivity of juveniles, sprouted tubers planted in closed containers were inoculated with cysts retrieved from the containers. After 4 weeks, the number of penetrated juveniles in the roots was determined. Quantification of volatile fatty acids (i.e., acetic, propionic, (iso) butyric, and (iso) valeric acid) in soil was done using gas chromatography coupled to a flame ionisation detector. Hydrogen sulphide, oxygen and carbon dioxide were also measured using gas chromatography. Inundation of non-amended soil caused 87% reduction in nematode survival after 8 weeks, while amending leek, steamed and fresh potato peels reduced the survival of G. rostochiensis in inundated conditions up to 99.9% after 4 weeks. Infectivity of juveniles was reduced after one week in inundated conditions compared with controls. However, no juveniles were observed in potato roots two weeks after inundation of amended soil. Visual assessment and the trehalose-based method showed the same survival results. In summary, application of agricultural waste amendments improved the effect of inundation on the survival of nematodes. Hereby, the depletion of oxygen and the formation of volatile fatty acids are involved in nematode suppression in soils amended with fresh and steamed potato peels, and leek. In addition, for leek the release of hydrogen sulphide, known to be toxic to nematodes, is probably also involved. Key words: potato cyst nematode, inundation, amendment, viability, volatile fatty acid

18


LONG-TERM EFFECTS OF SOIL TREATMENTS ON PLANT-PARASITIC NEMATODES, VERTICILLIUM DAHLIAE AND CROP YIELD J.H.M. VISSER, G.W. KORTHALS, W. VAN DEN BERG and L.P.G. MOLENDIJK WUR (PPO agv) Edelhertweg 1, NL-8219 PH Lelystad, The Netherlands

Arable soils are used more intensively than ever before and use of chemicals, as soil fumigants, to control plant pathogens is restricted due to availability of products and due to environmental restrictions. Therefore it becomes more important to maintain or even improve soil health (suppressive soils) to obtain profitable yields and to diminish the use and dependency of pesticides and artificial fertilizers. The withdrawal of most soil fumigants enhanced the need to develop sustainable methods for management of soil pathogens, such as Pratylenchus penetrans and Verticillium dahliae. Wageningen University and Research (PPO-agv) started in 2006 a long term field experiment to develop strategies to supress soil pathogens and improve soil health. On a sandy soil, naturally infested with Pratylenchus penetrans and Verticillium dahliae, eight different soil treatments (compost, chitin, marigold, grass-clover, bio fumigation, anaerobic soil disinfestation, a physical control method (Cultivit) and a combination of marigold, compost and chitin) and two reference treatments (a chemical control with 300 L/ha Metam sodium and un untreated control) were applied (2006 and 2009) within both organic and conventional cropping systems. Among others the effect of the treatments and cropping systems on P. penetrans population, V. dahliae and crop yield was studied. Additions of chitin and the combination treatment decreased number of micro sclerotia of V. dahliae comparable to metam sodium and anaerobic soil disinfestation performed even better. Chitin, anaerobic soil disinfestation, Metam sodium and the combination treatment decreased number of P. penetrans. Tagetes had the strongest and most sustainable effect on control of P. penetrans population. Bio fumigation, Cultivit and compost were not effective for control of plant parasitic nematodes and V. dahliae, when compared to untreated and the treatment with grass-clover even increased populations of P. penetrans and Trichorids. Effects of treatments on yield were, in general, inversely to the effects on plant parasitic nematodes and V. dahliae. Tagetes had the strongest and most durable positive effect on yield. An economic analysis of costs and yield improvement shows that tagetes was the most profitable treatment. Nett “economic yield” of Tagetes was €100,-/ha/year higher, compared to the untreated and even more profitable than chemical control with Metam sodium. The present study demonstrates that in comparison to chemical control, addition of chitin, anaerobic soil disinfestation and marigold are perfect alternatives for the control of plant-parasitic nematodes and/or V. dahliae. Key words: Soil treatments, Pratylenchus penetrans, Verticillium dahliae, crop yield, long term field experiment

19


RESISTANCE SCREENING OF TOMATO CULTIVARS TO MELOIDOGYNE INCOGNITA AND M. JAVANICA POPULATIONS FROM ETHIOPIA A.S. EBRAHIM, C. FININSA, T.M. MEKETE, W. DECRAEMER and W.M.L. WESEMAEL Nematology, Ghent University, Gent, Belgium

Soil and root samples were collected from major tomato growing areas of Ethiopia during the 2012/2013 growing season. Meloidogyne species were identified using DNA based identification techniques. Meloidogyne incognita and M. javanica were found to be the predominant root-knot nematode species across the sampled areas. The aggressiveness of the different populations of these two species were tested on two susceptible tomato cultivars (Marmande and Moneymaker). Of each species, the two most aggressive populations (‘Jittu’ and ‘Babile’ for M. incognita and ‘Jittu’ and ‘Koka’ for M. javanica) were further used to screen fourteen commercial tomato cultivars (ARPTomatod2, Bishola, Chalie, Cochoro, Eshete, Fetane, H-1350, Marglobe, Melkasalsa, Melkashola, Metadel, Miya, Moneymaker and RomaVF) commonly used in Ethiopia. Cultivar Marmande was used as a susceptible control. The resistance screening was done by inoculating 30 individual seedlings (4leaf stage) of each cultivar with 100 freshly hatched second-stage juveniles ( 20) and P. rhoeas (RI: 23.62) after treatment with metsulfuron-methyl. However, the metsulfuron-methyl resistant populations of M. recutita and S. media were sufficiently controlled with florasulam at the maximum authorised field dose. This was not the case for P. rhoeas. The metsulfuron-methyl resistant P. rhoeas population were also high-level resistant against florasulam (RI: 29.53). Integrated weed management practices (crop rotation, herbicide differentiation, ... ) should be applied to reduce the selection pressure for resistant weeds. Key words: Herbicide resistance, Matricaria recutita, Stellaria media, Alopecurus myosuroides, Papaver rhoeas

44

Session 3 Herbology 16:45

SENSITIVITY OF NATURALISED DIGITARIA AEQUIGLUMIS POPULATIONS TO 4-HYDROXYPHENYL PYRUVATE DIOXYGENASE- AND ACETOLACTATE SYNTHASE-INHIBITING HERBICIDES IN MAIZE B. DE CAUWER, E. DENDAUW and S. CLAERHOUT Weed Science Unit, Dept. Plant Production Faculty of Bioscience Engineering, Ghent University Coupure Links 653, BE-9000 Gent, Belgium

Until recently Digitaria aequiglumis var. aequiglumis (Hack. et Arechav.) Parodi, an alien species native to South America, was completely overlooked in Belgium due to its close morphological resemblance to Digitaria sanguinalis (L.) Scop. and Digitaria ischaemum (Schreb.) Mühlenb. Digitaria aequiglumis by now is firmly established and still under-recorded. One of the possible reasons for its expansion in maize fields, besides e.g. the lack of crop rotation, might be a lower sensitivity to postemergence herbicides acting against panicoid grasses, in particular 4-hydroxyphenyl pyruvate dioxygenase (HPPD)- and acetolactate synthase (ALS) inhibiting herbicides. Dose-response pot experiments were conducted in the glasshouse to evaluate the effectiveness of four foliar-applied HPPD-inhibiting herbicides (topramezone, mesotrione, tembotrione, sulcotrione) and two foliar-applied ALS-inhibiting herbicides (nicosulfuron, foramsulfuron) for controlling Belgian populations of D. aequiglumis. Local D. sanguinalis (L.) Scop. and D. ischaemum (Schreb.) Mühlenb. populations were used as reference populations. Herbicides were applied at the three-leaf stage (BBCH stage 13). Fresh biomass was harvested 28 d after treatment. In another dose-response pot experiment, the influence of growth stage at time of herbicide application on efficacy of topramezone and nicosulfuron for Digitaria control was evaluated. In general, sensitivity to mesotrione, tembotrione, sulcotrione, nicosulfuron and foramsulfuron was significantly lower for D. aequiglumis populations than for D. ischaemum and D. sanguinalis populations. Contrary to other herbicides tested, topramezone adequately controlled all D. aequiglumis populations at doses well below maximum authorized field dose. All species tested, showed a progressive decrease in sensitivity to topramezone and nicosulfuron with seedling age. Four-leaf stage plants of D. aequiglumis were tenfold less sensitive to topramezone and nicosulfuron than plants at the one-leaf stage. A satisfactory post-emergence control of Digitaria species in the field will require appropriate choice of herbicide and dose, as well as a more timely application. Key words: panicoid grasses, herbicide sensitivity, triketone, sulfonylurea, bioassay, leaf stage

45

Session 3 Herbology 17:05

EFFICACY OF METAMITRON IN APPLE THINING IN SERBIA M. STEVANOVIC1, N. DOLOVAC1, D. MARISAVLJEVIC1, A. ANDJELKOVIC1, L. RADIVOJEVIC2, G. ALEKSIC1 and V. GAVRILOVIC1 1

2

Institute for plant protection and environment Belgrade, Teodora Drajzera 9, Serbia Institute of Pesticides and Environmental Protection Belgrade, Banatska 31b, Serbia

The thinning of fruits is a required pomotechnical measure in intensive fruit production. This measure ensures the production of good quality fruits and high yields, while also regulating the fruits' productivity and reducing their natural alternate bearing tendency. The newest research shows that the photosynthesis inhibitors are also efficient in the thinning of apple fruits - two herbicides, terbacil and metamitron, known as inhibitors of photosynthesis, have been successfully used in the thinning of apple and peach fruits. This study had the aim to examine the activity of active matter, metamitron, on the thinning of apple fruits in the agro ecological conditions of Serbia and to evaluate the possibility of its practical application. Two varieties of apples that are widely grown in Serbia, Idared (Ajdared) and Golden Delicious (Zlatni Delišes), have been chosen for this research. The experiments were carried out during 2011 and 2012 according to the EPPO PP 1/158(2) method. The applied formulation contains 15% of metamitron, 150 a.e. g kg-1 of herbicide Metamitron 150 SG. The product which was tested was applied in quantities from 1.1 to 2.2 kg ha-1 in a single and/or split application in the growth stage when the fruits were 8 mm and 12 mm in size, depending on the variety. In the first year of research optimal manual thinning of fruits was used as a standard, while in the second year Maxcel product, as a compound registered for the application in the thinning of apple fruits, was used as a standard, in addition to the manual thinning. As the qualitative indicators from each tree in every experimental plot diameters of apple fruits were measured during harvest in order to evaluate the qualitative efficacy of metamitron and categorized in appropriate quality categories classes. The fruit categories were formed based on current unofficial market criteria of apple trade in Serbia. This two-year research has shown that the effect of metamitron on the thinning of apple fruits depends on multiple factors, primarily the application dose, time of the application, apple variety, but also on the number of fruits developed, i.e. the load of fruits on a single tree. Higher application doses cause stronger falling of fruits. With regards to the application time, in some apple varieties earlier application causes weaker, and later application stronger effect on the falling of fruits. Depending on the apple variety, it needs to be highlighted that some apple varieties (like the Idared) are prone to easier natural thinning, while others are less prone (like the Golden Delicious). This work was financially supported by the Ministry of Education and Science Republic of Serbia under the projects TR31018 and TR31043. Key words: Thinning, Metamitron, Apple

46

47

Session 4 FORMULATION AND APPLICATION TECHNOLOGY

48

49

Session 4 Formulation and Application Technology 11:00

DROP SIZE DISTRIBUTION MEASUREMENT OF ISO NOZZLES BY SHADOWGRAPHY METHOD N. DE COCK, M. MASSINON, S. OULED TALEB SALAH, B.C.N. MERCATORIS and F. LEBEAU Gembloux Agro-Bio Tech, Université de Liège Passage des Déportés 2, BE-5030 Gembloux, Belgium

Spray characteristics determine treatment performance and environmental contamination. Shadowgraphy associated with high-speed imaging presents an attractive option for measuring drop velocity and size simultaneously. This study presents an overview of the contrast problems occurring when using backlighted images and proposes appropriate solutions for reliable and quality measurements. Drop diameter measurement is based on the area inside the drop shadow, a sub-pixel contour is performed in order to improve the measurement accuracy. Drop velocity is determined by tracking a drop on two successive images taking into account the drop size, speed limits and the general flow direction. Then, the drop size distribution is corrected taking in account the sampling rate of each drop. Finally, a comparison between PDA and shadowgraphy measurements for 5 ISO nozzles is presented. Key words: Spray Drop Size Distribution Shadowgraphy

50


EFFECTS OF SPRAYING PARAMETERS ON THE VERTICAL SPRAY DISTRIBUTION OF ORCHARD AND VINEYARD SPRAYERS D. VON HÖRSTEN, J.K. WEGENER, H.J. OSTEROTH and T. ELZER Institute for Application Techniques in Plant Protection Julius Kühn-Institut (JKI), Federal Research Centre for Cultivated Plants Braunschweig, Germany

Streaking can be a problem during the application of pesticides if the nozzle formation comes too close to the target area. This problem is mainly known in vineyards, if the sprayer which is used is too large compared to the narrow rows or if there are problems with the adjustment of the sprayer (Knewitz 2009). We were interested to find out what spraying parameters are influencing the occurrence of streaking and which combination of these parameters can be used to optimize the adjustment of the sprayers. Therefore, we considered five different parameters (distance from nozzle to target, distance in between the nozzles, application pressure, type of nozzles and air-assisted spraying) and analyzed their influence onto the quality of the vertical distribution using a vertical patternator to measure the variation coefficient of the spray liquid distribution. We came up with the result, that the quality of the vertical distribution is influenced by all these parameters mentioned, but that the impact of the specific parameters can be quite different. The distance from nozzle to target, the type of nozzles used and the application technology (air-assisted or not) had the greatest impact on the quality of the vertical distribution. Furthermore, the tendencies of these impacts are mostly in the same way. Also the distance in between the nozzles and the application pressure had an impact on the quality of the vertical cross distribution, but the tendency of that impact was not clearly visible in all cases. The tentative experiments demonstrated that it could be very useful to investigate these and maybe some more parameters in order to optimize sprayer adjustment in future. Therefore, a lot of different parameter combinations have to be analyzed in further experiments. Key words: vineyard, orchard, sprayer, vertical distribution, streaks

51


DRIFT POTENTIAL OF TILTED SHIELDED ROTARY ATOMISERS BASED ON WIND TUNNEL MEASUREMENTS S. OULED TALEB SALAH, M. MASSINON, N. DE COCK, B. SCHIFFERS and F. LEBEAU Gembloux Agro-Bio Tech, University of Liege

Controlled Droplet Application (CDA), using shielded rotary atomizers, stands for an improved control of droplets diameters and trajectories compared to hydraulic nozzles. Unfortunately, these atomizers, because of their horizontal droplet release, are widely recognized to produce more drift than hydraulic nozzles. The present contribution investigates whether the setting of a rotary atomizer 60° forward tilted can reduce drift to acceptable levels in comparison with vertical and 60° forward tilted standard and low drift flat fan nozzles for the same flow rate. In a wind tunnel, the drift potential of a medium spray produced by a tilted shielded rotary atomizer Micromax 120 was benchmarked with that of a flat fan nozzle XR11002 fine spray and that of an anti-drift nozzle Hardi Injet 015 medium spray. Operating parameters were set to apply 0.56 l/min for every spray generator. Vertical drift profiles were measured 2.0 m downward from nozzle axis for a 2 m.s-1 wind speed. The tilted hydraulic nozzles resulted in a significant drift increase while droplets trajectories are affected by the decrease of the droplet initial vertical speed. Droplets emitted by the shielded rotary atomizer drift due to low entrained air and turbulence. A significant reduction of the cumulative drift was achieved by the rotary atomizer in comparison with flat fan nozzle while still being higher than the anti-drift nozzle. Unfortunately, the drift potential index (DIX) revealed that the cumulative drift reduction may not results in actual drift decrease because of higher drift at higher sampling locations. As a result, the DIX of the shielded rotary atomizer was similar to the standard flat-fan nozzle while the anti-drift nozzle reduced drastically drift as intended. Therefore, the 60° tilted rotary atomizer failed to reach low drift levels as expected despite the reduced span. Key words: Tilted shielded rotary atomiser, hydraulic nozzles, drift potential, wind tunnel.

52


COMPUTER SIMULATIONS OF SPRAY RETENTION BY A 3D BARLEY PLANT: EFFECT OF FORMULATION SURFACE TENSION M. MASSINON, N. DE COCK, S. OULED TALEB SALAH and F. LEBEAU Gembloux Agro-Bio Tech, University of Liege Gembloux, Belgium

Discriminating between the possible operating choices those providing the best efficacies for a given treatment is a daunting task since the numerous parameters involved are inextricably linked. Therefore, computational simulations were performed to provide an estimate of spray retention by a 3D barley plant. The aim of this study was to explore the range of liquid surface tension between pure water and a super spreader and highlight their effects on the spray retention by a single 3D barley plant. The main assumption made during simulations is still air hypothesis in order to focus only on the spray retention. The retention model used in this study was based on an algorithm that test whether droplets from a virtual nozzle intercept or not the plant model. If so, the algorithm determines the contribution of the droplet to the overall retention depending on the droplet impact behavior on the leaf; adhesion, rebound or splashing. The impact probabilities as a function of droplet impact energy were measured using high-speed imaging on a synthetic superhydrophobic surface both for water and the super spreader depending on the surface orientation. The modification of spray liquid properties in the simulations was performed by gradually changing the spray the droplet impact probabilities between the two measured boundaries. The plant architecture was modelled using a structured light scanner. The final retention was expressed as the volume of liquid retained by the whole plant relative to the projected leaf surface area in the main spray direction. 100 simulations were performed at 100 L/ha with a 11003 flat fan nozzle at 3 bars for each formulation surface tension. The coefficient of variation was used as indicator of variability of deposits. The model was able to discriminate between mixture surface tension. The spray retention increased as the mixture surface tension decreased. The variability of deposits also decreased as the surface tension decreased. The proposed modelling approach provides a suited tool for sensitivity analysis: nozzle kind, pressure, volume per hectare applied, spray mixture physicochemical properties, plant species, growth stage could be screened to determine the best spraying characteristics maximizing the retention. The model will be further extended with the real droplet trajectories in a moving airstream. Key words: spray retention, droplet impaction, surface tension, modelling, simulation

53


REDUCTION OF THE VOLATILISATION OF PESTICIDES FROM GLASS SURFACES BY ADJUVANTS M. HOUBRAKEN, D. SENAEVE and P. SPANOGHE Ghent University, Faculty of Bio-science Engineering, Department of Crop Protection Laboratory of Crop Protection Chemistry Coupure links 653, BE-9000 Gent, Belgium

After the application of plant protection products, a fraction of the active ingredient (a.i.) enters the atmosphere through volatilisation. This volatilised amount of pesticides contaminates the environment and reduces the protection of the crop. Vapour pressure of pesticides available in literature is determined of the pure component. Pesticide fate models used in risk assessment based on such vapour pressures do not incorporated the effect that pesticides formulations can have on the volatility. When pesticides are used in the field, a mixture of pesticides and adjuvants is used. Vapour pressure of such a mixture is not available. Dissipation of fenpropimorph, pyrimethanil, chlorpyrifos-ethyl and lindane as pure active ingredient, formulated by different types of adjuvants and in commercial formulation was studied. A polymeric surfactant (butyl block copolymer), an anionic surfactant (alkoxylated phosphate ester), a non-ionic surfactant (ethoxylated alcohol) and methylated seed oil were evaluated. The pesticides were applied in a wind tunnel and dissipation was measured up to 4 days after application. An empirical model assuming exponential decay of the volatilisation rate was used to calculate the volatilisation. Dissipation of fenpropimorph, pyrimethanil, chlorpyrifos-ethyl and lindane was according their vapour pressure. Our results demonstrated that in 48 hours, up to 90% of the pure fenpropimorph and lindane volatilises. Volatilisation of pesticides was also shown to be reduced up to 80% by the adjuvants. A commercial available formulation was able to reduce the volatilisation of pyrimethanil but the formulation of fenpropimorph had only a limited effect on its volatilisation. Further research on the mechanisms is required to fully understand the volatilisation processes and to evaluate the potential of adjuvants types to reduce the volatilisation of pesticides which is an addition to pesticide fate models. Key words: pesticide, volatilisation, formulation

54


SPRAY RETENTION VARIABILITY BY BARLEY H. BOUKHALFA and F. LEBEAU Department of Agronomy, Mohamed Khidar University, Biskra, Algeria Gembloux Agro-Bio Tech, University of Liege Gembloux, Belgium

The effectiveness of a phytosanitary treatment depends on the amount of product actually retained by the plant leaves relative to the volume per hectare applied. Parameters affecting spray retention include application variables such as nozzle type, operating pressure and formulation, and target properties such as species and growth stage. These variables condition more specific parameters such as the number of droplet impacts by unit area of leaf, the droplet size and velocity distributions at impact, droplet physicochemical properties (dynamic surface tension and viscosity) for the application variables and leaf wettability and plant architecture for the target. During a uniform treatment of the crop, each plant receives various droplet distributions that behave differently during impact depending on its architecture. In consequence, this contributes to increase the varying retentions observed between plants in field trials, leading in practice to apply an amount of product always greater than required to provide the level of crop protection needed for insuring high yields. The aim of this paper is to observe the retention variability that can occur during a treatment depending on the equipment, tank mix formulation and crop properties. The spray retention variability was assessed for three tank mix formulations: tap water, tap water with break thru, and tap water with Li700. For each formulation ten sprays were realized on five barley plants at the two leaves growth stage (BBCH stage 12) grown indoor in controlled conditions and ten sprays realized on individual barley plants at the same growth stage. The amount of spray actually retained by barley plants was assessed by dosing a fluorescent tracer added to the mixtures. Barley plants were placed linearly below the center of a moving nozzle at the speed of 2 m/s using a pressure of 2 bars. The last step was measuring leaf area for each spray and calculating the amount of sprays retained by barley plants to determine the variability of spray retention. Key words: surfactant, retention variability, barley.

55

Session 5 PESTICIDE APPLICATION AND PESTICIDE RESIDUES

56

57

Session 5 Pesticide application and pesticide residues 15:45

INDUSTRIAL-SCALE MALTING BARLEY SEED DISINFECTION BY MIST OF OZONATED WATER M. SPANOGHE, T. MARIQUE, O. ALLARD and M. VAN KONINCKXLOO Laboratory of Biotechnology Haute Ecole Provinciale de Hainaut-CONDORCET 17 Chemin du Champ de Mars, BE-7000 Mons, Wallonia, Belgium

The use of ozone treatment constitutes an alternative to chlorine and other chemical disinfectants which are currently used for crop disinfection. It is now well established that ozone is a powerful disinfectant against fungi, but also against bacteria and viruses due to its high biocidal efficacy. Ozone offers attractive advantages such as short half-life, quick auto-decomposition to produce oxygen and no undesirable residue left. With regard to ozone application in grain processing, gaseous ozone treatment (GOT) constitutes the most encountered disinfection application. However, it presents a health risk for users due to the direct contact with the strong oxidizing power of ozone. In this study, we developed a new disinfection application using a mist of ozonized water. From our perspective, this alternative method retains, through the physical properties of mist, many advantages over the GOT method, such as an improvement of the grain penetration efficiency, as well as a better stability in the germination of barley. It also presents less health hazards for users because ozone is being dissolved into water. Consequently, the operators’ contact with ozone was considerably attenuated, therefore not requiring the wearing of specifics masks. The pilot equipment starts with gaseous ozone production by corona discharge using an ozone generator, then gaseous ozone injection into water by a venturi and finally ultrasonic water mist production by applying a high-frequency to the water. The pilot equipment was placed within the processing plant of Malting Castle of Beloeil (Belgium) and disinfection was thus performed in real industrial conditions on seeds falling along a stainless steel drop plate. In total, three trials of 70 tons of barley seeds were achieved, each one corresponding to a specific concentration of dissolved ozone into water (7, 7.6 and 9.8 ppm respectively). From each trial, a sample of two kilograms of seeds was randomly picked up for the culture of fungal contaminants. The method of color discrimination by SelfOrganizing Maps was used to perform a digital analysis of colonies’ surface area, which was specifically developed to detect the simultaneous presence of Alternaria sp., Fusarium sp. and Aspergillus sp.. The disinfection of barley seeds by the new prototype within the malting firm process showed significant reduction of both Fusarium and Aspergillus fungi contaminants that were almost eradicated when the dissolved ozone concentration into water was increased up to 9.8 ppm. In contrast; Alternaria sp. appeared to be unsensitive to the treatment, regardless of ozone concentration. These results are promising for malting firms that are continually faced with problems from fungal contamination, causing germination or malting problems. Key words: Barley; Mist of ozonized water; Seed disinfection; Fusarium; Aspergillus

58


INNOVATIVE SOLUTION FOR THINNING APPLES AND PEARS A.J.M. BESSELING Maasdijk 48, NL-5328 BG Rossum, The Netherlands

BREVIS®, a novel, low dose formulation of metamitron, has been developed by Adama to increase fruit size and yield of marketable fruits. It also reduces costs of hand thinning by up to 80% when compared to other available solutions in the market, also reducing picking, storage and grading costs. For nearly a decade, Adama has worked closely with a team of advisers, researchers and growers to develop and test the BREVIS® formulation in a wide range of varieties, geographies, climatic conditions and agricultural practices. BREVIS® was found to be effective on all apple and pear varieties with flexible application guidelines at temperatures between 10 and 25 degrees Celsius, and on fruit sizes between 8 and 16 mm. Moreover, farmers can control the thinning effect by adjusting the application rate. BREVIS®, with its rapid leaf uptake, is less affected by the weather than other products currently on the market, in that rainfall more than two hours after application will not reduce its efficacy. “We have created a safer, more efficient formulation with lower toxicity, lower application rates and less residue compared to other fruit thinning agents on the market,” said Jean-Pierre Guerin, Adama’s European Herbicides and PGRs Manager. “In line with Adama’s vision to simplify processes for the farmers, we are proud to have developed a single solution, not based on plant hormonal activity, which achieves better results than other full fruit thinning programs that typically involve multiple steps.” The name Brevis (“short” in Latin) was chosen due to the brief, three week maximum duration of the product’s activity and the relatively short pre-harvest interval. Key words: ADAMA, BREVIS, launch, fruit thinner, apple and pear, metamitron, weather

59


BIODEGRADABLE PHEROMONE DISPENSERS MADE FROM ORGANIC MATERIALS FEATURING VARIOUS DESIRABLE QUALITIES AND SUITABLE FOR IPM OF VINEYARD INSECTS H.E. HUMMEL1,2 1

2

Justus-Liebig-University Giessen, Organic Agriculture Karl-Glöckner Straße 21 C, D-35394 Giessen, Germany E-mail: [email protected] University of Illinois, Prairie Research Institute, Urbana-Champaign, Illinois 61820, USA

Pheromones are considered modern plant protection agents with behaviour modifying qualities. They are usable in a variety of capacities for (i) pest insect monitoring, (ii) mass trapping, and (iii) mating disruption. In the course of the last half century, dispensers for pheromone application underwent a long series of developments from simple to complicated, from low tech to high tech, from cheap to expensive. Recently, the author developed sustainable organic electrospun mesofibers. Their advantages are: (1) Biodegradability, (2) manufacture from renewable resources, (3) inexpensive," semi-intelligent" design to compensate for UV and hydrolytically sensitive conditions, (4) time and labour saving combination with other mechanized work in the vineyard,(5) integrability with field robots, (6) lack of toxicity and eco-toxicity, and, unlike classical toxins, (7) very high specificity for one or only a very small number of insect species. Some of the features of this material will be highlighted by kinetic measurements of pheromone release and long-time stability in a laminar flow lab wind tunnel. The long list of substrates and dispensers tested over the years (laminates, ampoules, spaghetti type extruded plastic materials, fine mesh teflon cloth, cork, paper, cardboard, cellulose hollow fibers, ultrasound aided duster/vaporiser, also inorganics like sand, silica powders, glass and stainless steel planchets, recently is complemented by tests of biodegradable, low cost foamed wood material pressed into panels. Its properties as dispenser materials will be investigated in the near future by gravimetric measurements of pheromone evaporation rate over a period of several months. Key words: Lobesia botrana, mesofibers, Ecoflex®, biopesticides, pheromones

60


PILOT STUDY ON ESTIMATING NON-AGRICULTURAL USE OF PESTICIDES IN BELGIUM D. FEVERY1, E. LIEVENS2, L. JANSSENS2, C. BRAGARD2 and P. SPANOGHE1 1

2

Laboratory of Crop Protection Chemistry, Ghent University Coupure Links 653, BE-9000 Gent, Belgium Comité régional PHYTO, Earth and Life Institute, Université Catholique de Louvain Croix du Sud 2-L7.05.03, BE-1348 Louvain-la-Neuve, Belgium

Regulation (EC) No 1185/2009 of the European Parliament and the Council concerning statistics on pesticides covers both annual statistics on the placing on the market of pesticides and statistics on agricultural use of pesticides. There is a lack of knowledge on the pesticides used for non-agricultural purposes, so an indent was introduced in Section 6 of Annex II of the Regulation 1185/2009. According to this indent, Eurostat will take a lead in identifying the importance of commercial nonagricultural use of pesticides. To avoid possible false conclusions on the non-commercial and nonagricultural use of pesticides, Eurostat decided to carry out a pilot study on both commercial and non-commercial non-agricultural use of pesticides. In the first steps of the research the users of plant protection products were identified. A list of actors that contribute to non-agricultural use has been established. Second, a review of all different methods of data collection, already tested, has been performed for each category of users. Beside this review an identification of advantages and disadvantages of all different methods has been explained and a degree of certainty related to each method of data collection has been implemented. A proposal of the best data collection methods for each category of non-agricultural users has been presented. Third, a methodology for verifying the pesticide statistics of sales and uses of pesticides was set up. Key words: pesticides, agricultural and non-agricultural use

61


FIELD EVALUATION OF THE DISSIPATION RATES OF SELECTED PESTICIDES ON GREENHOUSE LETTUCE AND CUCUMBER AND SOIL-GROWN LEEKS D. SENAEVE, P. SPANOGHE1, S. POLLET, M. WUYTACK3, I. VANDEVELDE3 and A. BOGAERT4 1

Laboratory of Crop Protection Chemistry, Ghent University 2 INAGRO vzw, Rumbeke-Beitem 3 PSKW, Sint-Katelijne-Waver 4 PCG, Kruishoutem

Major food distribution chains have expressed concern about the amount of residual pesticides in food. To that effect, they have set quality standards that often exceed official standards. This puts a considerable burden on local farmers. A project was started to create a user-friendly model to help the farmers comply with the standards set by legislature and industry. This project is a collaboration between the university of Ghent, 3 agricultural research facilities and a number of pesticide producing companies. Field trials have been initialized in 2013. Crops of interest are lettuce, leeks and cucumber. For each crop, a selection of fungicides and insecticides were applied and the residue level in the plants was analyzed after certain time intervals. Results of the field trials show marked variation in both initial deposit and dissipation rates between the different crops and compounds. Residue levels in cucumber are much lower than both leek and lettuce. Across the crops, show similar relative dissipation rates. To model the dissipation rates, a selection of 4 basic models was evaluated. For short-term predictions, a first-order dissipation rate model is sufficient but for longer-term results more complex models are needed. The dissipation rate markedly slows down several days after application. For some compounds, a permanent residue seems to remain in the plant.

62

63

Session 6 PHYTOPATHOLOGY I

64

65

Session 6 Phytopathology I 11:00

NEW BNYVV P25 VARIANTS IN BELGIUM A. DECROËS1, M. CLAUSSE1, Y. GALEIN1, A. LEGREVE1, A. WAUTERS2 and C. BRAGARD1 1

2

Université Catholique de Louvain, Earth and Life Institute Applied Microbiology, Phytopathology Croix du Sud 2, Box L7.05.03, BE-1348 Louvain-la-Neuve, Belgium Institut Royal Belge pour l’Amélioration de la Betterave (IRBAB/KBIVB) Molenstraat 45, BE-3300 Tienen, Belgium

Rhizomania is a widespread viral plant disease of major importance in sugar beet crop and breeding. It is caused by the Beet necrotic yellow vein virus (BNYVV), a Benyvirus transmitted by the soil inhabiting plasmodiophorid Polymyxa betae. This vector also transmits other sugar beet virus such as Beet virus Q (BVQ) and Beet soil-borne virus (BSBV). Despite identification of resistance genes, BNYVV remains a major constraint because of resistance breaking events as well as its ability to survive for long periods in soils in resting spores of P. betae. During the 2014 growing season, severe rhizomania symptoms were detected on Rz1 resistant genotypes in ten fields in Belgium suggesting resistancebreaking events. Plants from these fields were sampled and total RNA was extracted from root hairs. The presence of BNYVV, BSBV, BVQ and P. betae was assessed by multiplex RT-PCR. Samples were then tested for the presence of RNA 5 and RNA 3 by RT-PCR respectively targeting P26 and P25 genes. PCR products for P25 were then purified and sequenced. The results confirmed the presence of P. betae, BSBV and BVQ in all samples. BNYVV was detected in nine fields. Sequencing of P25 partial cDNA sequences revealed the presence of BNYVV types A and B. Two isolates possessed amino acids motifs AYPR in the so-called tetrad region aa67-70. This motif was previously associated with resistance breaking events. The Belgian situation will be discussed in the light of the current situation in neighbouring countries. Key words: Beet necrotic yellow vein virus (BNYVV), P25, Resistance breakdown, Rhizomania, Sugar beet

66


CURRENT IMPACT AND FUTURE DIRECTIONS OF HIGH THROUGHPUT SEQUENCING IN PLANT VIRUS DIAGNOSTICS: THE DRIVERS OF COST ACTION 1407 T. CANDRESSE, A. OLMOS, A. BOONHAM, A. BÜTTNER, R. FELIX I. FONT, M. GLASA, R. JALKANEN, P. KOMINEK, M. LAIMER, T. MALINOWSKI, V. MALIOGKA, A. MINAFRA, N. ORTEGA, A. POLIVERARI, M. RAVNIKAR, D. SAFAROVA, R. VANDERVLUGT, C. VARVERI, J. WITZELL I. ZAGRAI, T. WETZEL and S. MASSART The affiliations and addresses of the contributors of this communication are listed in the COST website at the following address: http://www.cost.eu/COST_Actions/fa/Actions/FA1407?management Laboratory of Integrated and Urban Pathology Gembloux Agro-Bio Tech, University of Liège Passage des Déportés 2, BE-5030 Gembloux, Belgium

The ability to provide a fast, inexpensive and reliable diagnostic for any given viral infection is a key parameter in efforts to fight and control these ubiquitous pathogens. The recent developments of high-throughput sequencing (also called Next Generation Sequencing - NGS) technologies and bioinformatics have drastically changed the research on viral pathogens. It is now raising a growing interest for virus diagnostics. This presentation will provide a snapshot vision on the current use and impact of high throughput sequencing approaches in plant virus characterization. More specifically, this presentation highlights the potential of these new technologies and their interplay with current protocols in the future of molecular diagnostic of plant viruses. The current limitations that will need to be addressed for a wider adoption of high-throughput sequencing in plant virus diagnostics are thoroughly discussed. This paradigm change gave rise to the COST Action 1407 which is currently launched. This Action, its objectives and expected impacts will be presented. Key words: virus, diagnostic, high throughput sequencing, certification, pathogen

67


VIRUS INDEXING AND SANITATION OF INTERNATIONAL BANANA COLLECTION: INSIGHTS FROM A 5-YEARS COLLABORATIVE EFFORT C. DE CLERCK1, K. PARMENTER2, I. VANDENHOUWE3, L. LASSOIS1, N. ROUX4, M.H. JIJAKLI1, J. THOMAS2 and S. MASSART1 1

Integrated and Urban Plant Pathology Laboratory, Gembloux Agro-Bio Tech, ULg Passage des Déportés, 2, BE-5030 Gembloux, Belgium 2 Queensland Department of Agriculture, Fisheries and Forestry (DAFF) Level 2C West Ecosciences Precinct, GPO Box 267, Brisbane QLD 4001, Australia 3 Bioversity Transit Centre. Laboratory of Tropical Crop Improvement. K.U. Leuven Kasteelpark Arenberg 13, BE-3001 Leuven, Belgium 4 Bioversity International, Commodity Systems and Genetic Resources Programme, Parc Scientifique Agropolis II, 1990 Boulevard de la Lironde, FR-34397 Montpellier Cedex 5, France 5 The University of Queensland, Queensland Alliance for Agriculture and Food Innovation. Ecosciences Precinct, Level 2C west GPO Box 267 Brisbane Queensland 4001, Australia

The Bioversity International Transit Center for banana and plantain hosts 1455 accessions largely covering the genetic diversity of the Musa genus. Its objective is to conserve this genetic diversity and to supply plant materials to users worldwide. All the Musa accessions must be tested for virus and, if infected, sanitized to supply virus-free plant material. The international collaborative effort launched under the auspice of Bioversity to guarantee virus-free plant material will be described. During a five years period, 434 plant samples (in vivo, tissue culture) coming from 278 accessions, were preindexed by PCR for the presence of the 5 main viruses (BBTV, BanMMV, BrMV, CMV and BSV). At least one virus was detected in 67.4 % of the accessions received and the sanitation process started for 59 accessions. The virus indexing and plant certification was carried out on 243 accessions using another PCR protocol, electronic microscopy and symptom observation. 149 accessions were certified virusfree and released for international distribution from the ITC. Very practical observations with deep scientific impact have been made and addressed during this 5years window of activity. They are related to the material and timing of sampling, the testing redundancy in time and techniques, the comparison between results from independent diagnostics, the sanitation process accession-dependent, the extension of sanitized viruses… The presentation will address all these points underlining their importance for an efficient and reliable virus indexing and sanitation process. Key words: banana, virus indexing, international transit center

68


EPIDEMIOLOGY AND SUSTAINABLE CONTROL OF ZUCCHINI VIRUSES IN FLANDERS M. DE BACKER1, S. DARWICH2, D. CALLENS2, S. VENNEMAN3, L. ROOSTER3, M. MAES1 and K. DE JONGHE1 1

Institute for Agricultural and Fisheries Research (ILVO), Plant Sciences Unit Burg. Van Gansberghelaan 96, BE-9820 Merelbeke, Belgium 2 Inagro Ieperseweg 87, BE-8800 Rumbeke-Beitem, Belgium 3 Research Station for Vegetable Production Duffelsesteenweg 101, BE-2860 Sint-Katelijne-Waver, Belgium

The cucurbit viruses Cucumber mosaic virus (CMV; Cucumoviridae), Watermelon mosaic virus (WMV; Potyviridae) and Zucchini yellow mosaic virus (ZYMV; Potyviridae) are one of the major threats for zucchini cultivation in temperate and tropical regions. Due to a more than tenfold increase in zucchini production in Flanders during the last 20 years, zucchini viruses gained importance as well. These viruses are transmitted by aphids in a non-persistent way and cause comparable symptoms in zucchini including mottling, mosaic, chlorosis and distortion of the leafs or discoloration and fruit abnormalities. This leads to important yield reductions and unmarketable fruits. In order to gain knowledge about the epidemiology of these viruses and their vectors in Flanders and to work out a sustainable control strategy, a four year research project was conducted. Based on an extensive survey between 2007 and 2013, we observed a clear shift in the virus populations. The level of ZYMV decreased, the level of CMV infections increased until a dropdown in 2013 while the number of WMV infections remained relatively constant until an important increase in 2013. As economical damage related to plant symptom development , and a consequent reduction of yield and fruit quality can be mostly attributed to WMV infections, the genetic variability of a selection of WMV isolates from different growing seasons was tested by amplification and sequencing part of the coat protein. This revealed the introduction of a new genotype in 2010 that was able to establish in the succeeding years. In addition to zucchini, different weed species and the aphids were monitored for the presence of the studied viruses. Several weed species were identified to be an important reservoir host for CMV and to a lesser extent for WMV. The number of aphids in the sampled fields were relatively low. However, Aphis gossypii was most abundant in zucchini fields and can be considered the most important vector with regard to virus spread. Based on cultivar trials, it was clear that symptom development and yield reduction due to virus infection strongly depended on the cultivar. In case of CMV we also noticed that symptomless plants in general didn’t contain the virus, indicating resistance. This is in contrast to WMV plants where cultivars that didn’t develop symptoms upon infection appeared to be latently infected indicating tolerance rather than resistance. To avoid spread of the tested viruses during cultivation practices, we tested a selection of disinfection agents for their efficiency on tools. This revealed partial activity for some products. In conclusion it can be stated that sustainable management of zucchini viruses can be achieved by a combination of control measures. These include a selection of resistance or tolerant cultivars, thoughtful weed and aphid control and good cultivation hygiene including disinfection of harvest equipment. Key words: Cucumber mosaic virus, Watermelon mosaic virus, Zucchini yellow mosaic virus, cultivar trial, survey

69


TRANSCRIPTS DIFFERENTIALLY EXPRESSED IN SILICON SUPPLEMENTED CUCUMBER CULTURES AND THEIR POTENTIAL ROLE FOR CUCUMBER MOSAIC VIRUS INFECTION S. HOLZ1, M. KUBE1, G. BARTOSZEWSKI2, B. HUETTEL3 and C. BÜTTNER1 1

2

Division Phytomedicine, Albrecht Daniel Thaer-Institute Humboldt-Universität zu Berlin Lentzeallee 55/57, DE-14195 Berlin, Germany Department of Plant Genetics, Breeding and Biotechnology, Warsaw University of Life Sciences 159 Nowoursynowska Street, PL-02-776 Warsaw, Poland 3 Max Planck Genome Centre Cologne Carl-von-Linné-Weg 10, DE-50829, Cologne, Germany

The uptake of Silicon (Si) by plants enables protection against various stresses. The plant available form, silicic acid [Si(OH)4], is taken up by the roots, transported to the leaves and finally deposited as silica gel in the space beneath the cuticle layer. To date, Si is seen as a “quasi-essential” element for plants. Beneficial effects are: 1) protection against abiotic and biotic stresses, 2) improvement of physical stability, 3) higher yield and/or 4) disease resistance. Therefore, routinely application of fertilizers supplemented with Si is performed. Besides the improved mechanical barrier and passive defence due to Si incorporation in cell walls, continuous Si uptake plays a substantial role for defence and consequently disease resistance. Many beneficial effects were shown for plants infected with biotrophic fungi. Up to now, the role of Si with regard to plant viruses is not clarified. Cucumis sativus line B10 in vitro cultures were chosen to reveal genes altered due to Si supplementation followed by Cucumber mosaic virus (CMV; family: Bromoviridae) infection. Direct regeneration of cucumber clones was performed derived from leaf micro explants. The plants were cultivated on Murashige and Skoog medium. Si was supplemented as Na2(SiO2)xxH2O and the medium for control plants contained NaCl in equal amounts. Six rooted plantlets, three control and three Si pre-treated, were mechanically inoculated with CMV. 10 days post inoculation, pooled leaf and stem material from three non-infected and six CMV infected plants was taken. Total RNA was isolated followed by DNaseI treatment. Absence or presence of viral infection was analyzed by performing reverse transcription (RT)-polymerase chain reaction (PCR). Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed on selected genes related to CMV infection. Clonal plant material was successfully established and subsequently cultivated in regeneration medium. Experiments inducing CMV-infection were successfully applied in the in vitro cultures and RNA of control, CMV infected and Si pre-treated and CMV infected plants was obtained. Removal of DNA was confirmed by performing qRT-PCR on an intronic sequence of the endogenous control. qRT-PCR performed on selected host genes involved in defence response (WRKY transcription factor), viral movement and replication (chaperones), resulted in both beneficial and disadvantageous gene shifts due to Si supplementation. Here, we provide a basis for the potential neutral effect of Si on transcript level, proven by qRT-PCR, in cucumber cultures with regard to a plant virus infection. Key words: silicic acid, Bromoviridae

70


CITRUS PLANTS AFFECTED BY HUANGLONGBING HOST MULTIPLE POPULATIONS OF CANDIDATUS

LIBERIBACTER ASIATICUS A. CAMPISANO1,2, P. BELLA3, C.P. STRANO3, G. LICCIARDELLO4, R. LA ROSA3 and V. CATARA3 1

Sustainable Agro-ecosystems and Bioresources Department, Fondazione Edmund Mach (FEM) via E. Mach 1, IT-38010 S. Michele all ‘Adige (TN), Italy 2 Laboratory of Phytopathology, Department of Crop Protection, Gent University Coupure links 653, BE-9000 Gent, Belgium 3 Dipartimento di Agricoltura, Alimetazione e Ambiente, Università di Catania, Catania, Italy 4 Parco Scientifico e Tecnologico della Sicilia, Catania, Italy

Huanglongbing (HLB) is an infectious disease of citrus trees. The phloem-limited Candidatus Liberibacter asiaticus is associated with HLB. We studied microbial populations in bark and leaf midrib tissues of infected citron and mandarin trees in China. The presence of Ca. Liberibacter was quantitatively assessed via qPCR. The sample DNA was used for whole-community analysis using pyrosequencing of the 16S rDNA region. Contrary to the expectations, qPCR indicated that barks were more heavily colonized that leaf midribs. Whole-community analysis indicated that citrus and mandarin trees shared a large portion of their bacterial populations. Bacterial communities associated with bark and midrib were also highly similar. Despite the similarities, samples from the different species and tissues could be grouped in a Principal Coordinates Analysis plot generated using UniFrac distances. Using pyrosequencing we detected Ca. Liberibacter sequences in all samples. We noted that the relative frequency of sequences under the order Rhizobiales was constant and unaffected by the variables considered in this work. Increased numbers of Ca. Liberibacter corresponded to fewer sequences assigned to other families in the Rhizobiales (chiefly Methylocystaceae and Methylobacterium). Four separate OTUs were classified as Ca. Liberibacter. The majority of samples hosted multiple (2-3) OTUs of Ca. Liberibacter, and the control sample (whose bacterial micro fauna was dominated by Ca. Liberibacter) hosted all four OTUs of the pathogen. Our findings show that during development of HLB disease, citrus trees harbour multiple populations of Ca. Liberibacter, and raise new questions on their significance for the ecology and pathogenesis of this bacterium. Key words: Huanglongbing, Candidatus Liberibacter asiaticus, citrus, pyrosequencing

71


INCIDENCE AND SEVERITY OF LEAF AND FRUIT DISEASES OF PLUMS IN LATVIA L. GRANTINA-IEVINA and L. STANKE Horticultural Crop Pathology Group Latvian Plant Protection Research Centre, Ltd Struktoru 14a, LV-1039 Riga, Latvia E-mail: [email protected]

In the investigation six plum orchards in Latvia were examined in 2014. One orchard was commercial with integrated pest management (IPM) practices, one was with organic management, two orchards were scientific collections and in two orchards plums were grown as a minor crop, using IPM practices. The shot-hole disease (Wilsonomyces carpophilus) and fruit rot were monitored in the field. Samples of twigs and leaves were taken for further examination if some other disease symptoms were observed. In total 50 European plum (Prunus domestica) and six diploid plum cultivars were inspected. The fruit rot was assessed also in the laboratory to determine the latent infection with Monilinia spp. on immature fruits. Monilinia spp. isolates from all orchards were subjected to fungicide sensitivity tests. Incidence and severity of shot-hole disease was significantly different among various orchards comparing the same cultivar, as well as between diploid and European plum cultivars. The average incidence of shot-hole disease was 41 % in diploid plums and 80 %, in European plums, while the average severity was 9 and 15 %, respectively. In the field fruit rot caused only by Monilinia spp. was detected. The average incidence of brown rot on diploid plums was less than 1 % but on European plums it was 3.6 %. The latent infection tests showed that plum fruits had higher incidence of brown rot than was observed in the field, up to 44 % on particular cultivars. Additionally from the fruits subjected to these tests Botrytis cinerea, Diaporthe eres and Colletotrichum spp. were isolated. This means that in specific weather and management conditions the fruit rot incidence in the field could be several times higher. Examination of samples of twigs, leaves and fruits in the laboratory showed the presence of D. eres in samples from all orchards. In one of the scientific collections D. eres was isolated from twigs, leaves and fruits, and was more often found on the individuals located in the part of the orchard close to hedge. In other orchards this fungus was isolated only from fruits, and mainly from the latent infection tests. Several fungi that are known to be antagonistic to pathogenic fungi were isolated from all orchards: Epicoccum nigrum, Clonostachys rosea and Aureobasidium pullulans, mainly from the fruits of latency tests and leaves with disease symptoms. Monilinia spp. isolates showed high sensitivity to dithianon, penconazole, mancozeb and boscalid with piraclostrobin but lower sensitivity to ciprodinil. Key words: plums, Wilsonomyces carpophilus, brown rot, latent infections, Diaporthe eres

72


EFFECT OF SILVER NANOPARTICLES USED WITH SODIUM BICARBONATE ON PENICILLIUM DIGITATUM PATHOGENESIS G. D'HALLEWIN, L. CUBAIU, G. LADU G. PETRETTO* and T. VENDITTI ISPA-CNR, Traversa la Crucca 3 Loc. Baldinca, IT-07040 Sassari, Italy E-mail: [email protected] * Department Chemistry and Pharmacology-UNISS Via Muroni 23, IT-07100 Sassari, Italy

Data non the research concerned with the fungicidal properties of a nano-sized silver colloidal solution employed alone or in combination with sodium bicarbonate as an antifungal treatment against Penicillium digitatum, the cause of citrus green mould will be presented. Silver nanoparticle (AgNP 10~25 nm), obtained by an eco-friendly nanobiotechnology, was used alone at three concentrations (50, 100 and 150 ppm) or combined with 1% sodium bicarbonate (SBC). The in vito assay was performed on AgNP/SBC amended PDA at the mentioned concentrations, and as control un-amended PDA was employed. After 48 h, agar plugs (8 mm) containing 7 d old actively growing P. digitatum were inoculated at the center of the PDA-amended and control Petri dishes. The experiment was repeated twice with 3 replicates for each treatment (N=3x8). The in vivo experiment was carried out with ‘Nova’ mandarin hybrid (Citrus reticulata). Fruit were surface sterilized, rinsed, and when dry wounded at 3 points at the equatorial area. In order to gain knowledge on the curative and preventative activity of the treatments, two experiments were performed: A) one h old wounds were inoculated with a 2x105 P. digitatum spore concentration and keep 24 h at 25°C before treatment with AgNP/SBC; and in experiment B), one h old wounds were first treated with AgNP/SBC and after 24 hr inoculated with the pathogen suspension. In comparison to un-amended PDA, the in vitro trail evidenced a clear inhibition in all amended media. The inhibition efficacy rose by increasing the AgNP concentration and was significantly improved when combined with SBC. Concerning the in vivo experiment, it was clear that AgNP exerts mainly a preventative activity, while SBC acts effectively as a curative agent. When the two treatments were combined a significant synergistic effect occurred, and disease severity with 150 ppm AgNP was completely controlled in both experiments (A, B). Interestingly, the interaction between AgNP and SBC improved the curative and preventative activity of the single treatments, indicating a different mode of action. Key words: nanobiotechnology, postharvest, decay, treatments

73


INFLUENCE OF ADDITIVES ON THE EFFICIENCY OF BCOS AGAINST POME FRUIT STORAGE DISEASES T. VANWALLEGHEM1, D. DEKEYSER2, D. NUYTTENS2, A. TSIGE3, P. VERBOVEN3, D. BYLEMANS1 and W. VAN HEMELRIJCK1 1

Research Station for Fruit Cultivation (pcfruit npa), Department Mycology BE-3800 Sint-Truiden, Belgium 2 ILVO, Technology and Food Science, Agricultural Engineering BE-9820 Merelbeke, Belgium 3 KU Leuven, Department MeBioS BE-3001 Heverlee, Belgium

Storage diseases of pome fruits are caused by different fungal species. Disease management to control storage diseases includes several treatments with different fungicides in the weeks prior to harvest. However, the presence of residues on fruits becomes more and more a public and governmental concern. In order to reduce the chemical residue on fruits to a minimum, more and more research is done on alternative disease management. In this context, in 2013, a research project concerning the atomization of biological control organisms in cold storage to control storage diseases, funded by the Agency for Innovation by Science and Technology, was started at the pcfruit institute in collaboration with ILVO and KU Leuven. In this project, the efficiency of biological control organisms (BCOs), applied through specific atomization in the cold storage, on storage diseases will be examined and improved. At first, the influence of fungicides applied in the months prior to storage was evaluated on different BCOs. Besides that, also the influence of additives on the efficiency of BCOs in their control of storage diseases was investigated. Two groups of fungal pathogens causing storage diseases can be distinguished. The first group comprises the latent fruit rot pathogens like Neofabraea spp., which infect the fruits already in the orchards through natural openings like lenticels. For this type of pathogens symptom expression is delayed till after a long storage period. The second group are the wound pathogens (Botrytis cinerea, Monilia spp., Penicillium spp.) that penetrate the fruits through accidental wounds, for example during picking. Both groups of fungal pathogens were included in the tests. However, not only the efficacy of the BCOs is important but also the homogeneous distribution of the compounds in the cold storage room. The first results of this project will be presented. Key words: BCO, Storage diseases, Additives, Cold Storage, Atomization

74

75

Session 7 PHYTOPATHOLOGY II

76

77

Session 7 Phytopathology II 11:00

PRE-PLANTING TREATMENTS WITH PHOSPHITE-BASED PRODUCTS AGAINST DIFFERENT FOLIAR AND SOIL-BORNE PATHOGENS OF VEGETABLE CROPS G. GILARDI, S. DEMARCHI, I. RAMON M.L. GULLINO and A. GARIBALDI Centre of Competence for the Innovation in the agro-environmental field (AGROINNOVA), University of Torino Largo Braccini 2, IT-10095 Grugliasco (TO), Italy DISAFA, University of Torino

During the past few years many new diseases caused by foliar and soil-borne pathogens have been detected in Italy on crops grown for the horticultural industry such as the salad crops for the readyto-eat sector, mainly as a result of their intensive cropping system. At the same time, increased attacks of several already known soil-borne diseases such as Phytophthora crown root rot and Fusarium wilts are reported as a consequence of the changes undergone in soil disinfestation. Many of these pathogens are transmitted through seeds. The management of foliar and soil-borne disease is difficult because the number of chemicals registered for use is relatively low especially for minor crops and further limitations affect soil fumigants. Therefore, especially in intensive cropping systems, the interest on disease management strategies alternative to chemicals increased. Experiment al trials were carried out in greenhouse to evaluate the efficacy of preventative treatments based on phosphite salts in disease management on the following pathosystem: tomato/Phytophthora nicotianae; zucchini/P. capsici; lettuce/Fusarium oxysporum f.sp. lactucae; rocket/Fusarium oxysporum f.sp. raphani; rocket/Plectosphaerella cucumerina, basil/Peronospora belbahrii. Phosphites-based products reduced of 66-88% and of 56-72% the severity of Phytophthora crown root rot of tomato and zucchini, respectively. Four applications with the phosphites-based products provided a disease reduction of Fusarium wilts of lettuce from of 32.6 to 83.1% and of 44.8 to 67.7% on cultivated rocket. These products provide the most constant results when applied in three treatments against Plectosphaerella cucumerina with a disease reduction ranging between 34% and 82%. Phosphites-based products showed results statistically similar to metalaxyl when tested against downy mildew of basil. Their possible use in application under nursery cultivation systems are considered comparable with chemical reference fungicides. Results of trials carried out in the presence of artificial inoculation of emerging pathogens are reported, with a critical analysis of their positive and negative features. Key words: : leafy vegetables, Fusarium wilts, Phytophthora crown root rot, downy mildew

78


79


IDENTIFICATION OF DIFFERENT FUSARIUM SPP. ON ALLIUM SPP. IN GERMANY B. BOEHNKE1, P. KARLOVSKY2, K. PFOHL2, A. GAMLIEL3 Y. ISAAK 3 and H-W. DEHNE1 1

Rheinische Friedrich-Wilhelms University Bonn Inres - Phytomedicine - Plant Disease and Plant Protection Meckenheimer Allee 166a, DE-53115 Bonn, Germany 2 Georg-August-University Goettingen Molecular Phytopathology and Mycotoxin Research Grisebachstr. 6, DE-37077 Göttingen, Germany 3 Laboratory For Pest Management Research Institute Of Agricultural Engineering (Aro) The Volcani Center, Bet Dagan 50250, Israel

The most important Fusarium species causing Fusarium basal rot of onion is Fusarium oxysporum in Germany. However, in Mediterranean countries like Israel the Fusarium salmon blotch caused by Fusarium proliferatum is more important than F. oxysporum. The aim of the survey was to evaluate different Fusarium spp. infecting onions and show the increasing importance of mycotoxin producing fungi like F. proliferatum in Germany. In 2013 Allium cepa bulbs from different fields in Northern and Southern Germany, seeds and sets from German onion breeders as well as different edible Allium spp. from local markets were detected for infestation with Fusarium sp.. Different Fusarium spp. were isolated and identified by morphological characterization. More than 20 different Fusarium spp. were identified. The examined Allium seeds were free of Fusarium infection, but Fusarium contaminations on the surface were detected. The diversity of Fusarium spp. and the intensity of infestation was higher on edible bulbs compared to the younger sets. The most common species in onions from field are F. oxysporum and F. solani. This species could be identified on every onion field. On average 4 different Fusarium spp. per onion field and 2 different Fusarium spp. per onion were detected. Fusarium sp. was identified in onions with and without visible symptoms. It could be detected no differences between the Fusarium infestation on onions in the North and the South of Germany and between the different analyzed Allium varieties. The analyzed onions and other eatable Allium spp. from local markets showed also a high content of different Fusarium spp.. The main identified Fusarium sp. in the different analyzed Allium spp. in Germany was F. oxysporum. Fusarium proliferatum could be detected in about half of the sampled onion fields and in approximately 10% of all analyzed onions. Also in the onion sets, on the surface of the seeds and in other eatable Allium spp. F. proliferatum were identified. Besides F. proliferatum further mycotoxin producing Fusarium spp. like F. equiseti or F. tricinctum were identified. Other Fusarium spp. like F. sporotrichioides and F. poae were first described in Allium sp. The two main Fusarium spp. are able to produce mycotoxins like Enniatins, Fumonisins, Moniliformin and T-2 toxins. Further detected Fusarium sp. like F. proliferatum, F. equiseti and F. tricinctum are able to produce additional toxins like Beauvericin, Zearalenone and Diacetoscirpenol. This broad spectrum of possible Fusarium mycotoxins could be a potential health risk for human beings and livestock. Key words: Fusarium Allium onions mycotoxins

80


OPTIMIZED INFESTATION CONTROL AND MYCOTOXIN REDUCTION STRATEGIES AGAINST FUSARIUM DISEASES OF CORN AND WHEAT J.A. VERREET and T. BIRR University of Kiel, Institute of Phytopathology Herrmann-Rodewald-Str. 9, DE-24118 Kiel, Germany

The epidemic and damage dynamics of 13 Fusarium species on wheat (3 different susceptible varieties, 2008-2014) and corn (4 different susceptible varieties, 2011-2014) were recorded at 9 locations in Schleswig-holstein, Germany. In addition to yield factors, disease severity were analysed by q-PCR and the Fusarium toxins deoxynivalenol (DON) and zearalenone (ZEA) were analysed by LC/MS. The same Fusarium spp. spectrum was detected in wheat and corn. Based on year-long national results, a head blight forecast model for the optimized control was derived for wheat. There was a close relationship between rainfall and temperature at flowering (infection parameters) on the one hand and Fusarium-DNA (R2 = 0.78), DON (R2 = 0.80), and ZEA content (R2 = 0.76) of the grain on the other. The correlation between mycotoxin contents and Fusarium-DNA at harvest and predicted values which were calculated on temperature and precipitation at flowering document the high quality of the model (DON R2=0.85, ZEA R2=0.86, Fusarium DNA R2=0.83). Both in susceptible and tolerant corn varieties, maximum values of > 26 000 micrograms DON and > 2000 micrograms ZEA per kg dry mass were measured in no-till cropping systems with monoculture. Plowing reduced DON content by 82 % and ZEA content by 65 %. The triazole fungicides metconazole, prothioconazole, and tebuconazol combined with strobilurines reduced mycotoxin levels in wheat by ≥ 60 %, and in corn by up to 90 % when applied at flowering and panicle stage, respectively. Key words: Fusarium spp., Mycotoxins, control, prognosis system

81


EXPOSURE TO GREEN LEAF VOLATILES PRIMES WHEAT AGAINST FHB BUT BOOSTS PRODUCTION OF THE MYCOTOXINE DON M. AMEYE1,2, K. AUDENAERT2, N. DE ZUTTER1,2, K. STEPPE3, L. VAN MEULEBROEK4, L. VANHAECKE4, D. DE VLEESSCHAUWER5, G. HAESAERT2 and G. SMAGGHE1 1

4

Laboratory of Agrozoology, Department of Crop Protection Faculty of Bioscience Engineering, Ghent University Coupure Links 653, BE-9000 Ghent, Belgium 2 Department of Applied Biosciences Faculty of Bioscience Engineering, Ghent University Valentin Vaerwyckweg 1, BE-9000 Ghent, Belgium 3 Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University Coupure Links 653, BE-9000 Ghent, Belgium Laboratory of Chemical Analysis, Department of Veterinary Public Health and Food Safety Faculty of Veterinary Medicine, Ghent University Salisburylaan 133, BE-9820 Merelbeke, Belgium 5 Laboratory of Phytopathology, Department of Crop Protection Faculty of Bioscience Engineering, Ghent University Coupure Links 653, BE-9000 Ghent, Belgium

Priming refers to a mechanism whereby plants are sensitized to respond faster and/or more strongly to future pathogen attack. Here, we demonstrate that pre-exposure to the green leaf volatile (GLV) Z3-hexenyl acetate (Z-3-HAC) primed wheat (Triticum aestivum L.) for enhanced defence against subsequent infection with the hemibiotrophic fungus Fusarium graminearum. Bioassays showed that after priming with Z-3-HAC wheat ears accumulated up to 40% less necrotic spikelet’s. Furthermore, leaves of seedlings showed significantly smaller necrotic lesions compared to nonprimed plants, coinciding with strongly reduced fungal growth in planta. Additionally, we found that F. graminearum produced more deoxynivalenol, a mycotoxin, in the primed treatment. Expression analysis of salicylic acid (SA) and jasmonic acid (JA) biosynthesis genes and exogenous MeSA and MeJA applications showed that plant defence against F. graminearum is sequentially regulated by SA and JA during the early and later stages of infection, respectively. Interestingly, analysis of the effect of Z-3-HAC pre-treatment on SA and JA-responsive gene expression in hormone-treated and pathogen-inoculated seedlings revealed that Z-3-HAC boosts JA-dependent defences during the necrotrophic infection stage of F. graminearum but suppresses SA-regulated defence during its biotrophic phase. Together these findings highlight the importance of temporally separated hormone changes in moulding plant health and disease and support a scenario whereby the GLV Z-3-HAC protects wheat against Fusarium head blight by priming for enhanced JA-dependent defences during the necrotrophic stages of infection. Key words: Fusarium, Z-3-hexenyl acetate, priming, plant defence, green leaf volatile

82


SnRK1 POSITIVELY REGULATES RICE BASAL IMMUNITY O. FILIPE, D. DE VLEESSCHAUWER and M. HÖFTE Laboratory of Phytopathology, Department of Crop protection Ghent University, Ghent, Belgium

Upon pathogen attack plants rapidly shift cellular resources from growth to defence responses. As a result processes involved in plant growth and development are stopped leading to growth inhibition. Despite its crucial importance for plant survival and reproduction, little is known about the gene expression and mechanisms underpinning this innate trade-off between plant growth and immunity. Therefore, we investigated the involvement of SnF1-related kinase 1 (SnRK1), an evolutionary conserved protein kinase that tightly control eukaryotic energy homeostasis, in rice (Oryza sativa) basal immunity. SnRK1 is the plant ortholog of AMP-activated kinase (AMPK) from mammals and SnF1 from yeast. In these organisms, SnRK1 responds to cellular energy deficits by suppressing energyconsuming biosynthetic processes and promoting catabolism. Our studies revealed that OsSnRK1 is involved in plant growth and development as increased levels of OsSnRK1 were not only accompanied with loss of biomass but also yield loss, since overexpressing plants in the Kit-XA21 background produced fewer seeds compared to controls. These findings corroborate the role of this kinase found in other organisms, where SnRK1 has been linked to growth and development by interacting antagonistically with target of rapamycin (TOR), a Ser/Thr kinase well known for coordinating growth and development. Furthermore, in accordance with data from animal systems where there are strong connections between SnRK1 and defence signalling, our findings also implicate OsSnRK1 in the rice hormone and defence signalling networks. Our studies revealed that OsSnRK1 overexpressing mutants displayed high levels of resistance against both (hemi)biotrophic (Xantomonas oryzae pv oryzae (Xoo)) and necrotrophic (Cochliobolus miyabeanus (Cm)) pathogens. In contrast, OsSnRK1 downregulation increased susceptibility towards Xoo in experiments using SnRK1-RNAi mutants in the KitXa21 genetic background. Experiments using rice cell cultures further revealed that SnRK1 not only serves as a positive regulator of basal immune response but also orchestrates plant hormone signalling. In the presence of chitin, SnRK1 activation led to significant higher expression of PAMPresponsive genes and of SA- and JA-responsive defence genes. Moreover our data showed that SnRK1 activation increases the expression of genes involved in JA-biosynthesis pathway. Accordingly, activation of SnRK1 seems to increase auxin and brassinolide responsive genes and to inhibit gibberellins responses by increasing expression of GA inactivating protein (GA2OX). Moreover, in line with the strong induction of SA- and JA-responsive genes in the presence of SnRK1 activator and/or PAMP, our Western blot data suggest that exogenously administrated SA and JA positively affect the level of SnRK1 activation in co-application with metformin, the most commonly used antidiabetic drug known to indirectly activate AMPK. Strikingly, chitin presence was enough to significantly boost OsSnRK1 activation levels. These findings strongly indicate SnRK1 to be involved in plant basal immunity, supporting a model whereby SnRK1 acts as a master switch that, upon stress perception, relocates energy and biochemical resources away from growth and development and into defence responses. Key words: SnRK1, defence, Oryza sativa

83


PLANT OLIGOSACCHARIDES ENHANCER OF WHEAT DEFENSE RESPONSE AGAINST SEPTORIA LEAF BLOTCH L. SOMAI-JEMMALI1, A. SIAH2, B. RANDOUX2, Ph. REIGNAULT3, P. HALAMA2, R. RODRIGUEZ4 and W. HAMADA1 1

Laboratoire de Génétique, Institut National Agronomique de Tunisie, TN-1082 Tunis, Tunisia Biotechnologie et Gestion des Agents Pathogènes en agriculture-Institut Charles Viollette, GIS PhyNoPi, Institut Supérieur d’Agriculture, FR-59046 Lille cedex, France Unité de Chimie Environnementale et Interactions sur le Vivant, Université du Littoral Côte d’Opale FR-62228, Calais cedex, France 4 Sustainble Agro Solution N-240, ES-25100 Almacelles, Lleida, Spain 2

3

This study aims at characterizing the efficiency and the mode of action of a new formulation based on patented mix of polysaccharides + organic acids + vitamins (PF5) compared to reference chitosan (CHT), on Mycospharella graminocola infection during compatible interactions with durum wheat (DW) and bread wheat (BW). On one hand, our work revealed that PF5 treatment was more efficient than CHT to decrease septoria disease level, leaf penetration, colonization and fructification. It promoted at least 5-fold protection, while CHT present lower than 2-fold protection. Besides, PF5 allowed to drastically decrease the production of CWDE activities by M. graminicola, such as xylanase, glucanase and protease, during the necrotrophic phase of the infection. In the other hand, elicitor and potentiating effect of wheat defence mechanisms were investigated by molecular, biochemical and microscopic analysis.PH5 exhibited both elicitor and potentiating effect on PR-proteins (PR2, PR4 and PR9), lipoxygenase (LOX-1)-encoding gene’s expressions. At the enzymatic scale, it presented an elicitor effect on β-1,3-glucanase and LOX activities, in both wheat species and a potentiating effect on LOX and PAL activities in BW leaves. Microscopic observations showed the induction of polyphenols and H2O2 accumulation only after inoculation, at M. graminicola penetration sites. Moreover, PF5 treatment had an elicitor effect on total phenolic compounds (PC) accumulation. CHT treatment induced higher and more durable enzymatic activities and cytological reactions, while it didn’t induced any PC accumulation in wheat leaves. Our work exhibited distinct response profiles of DW and BW to tested treatments. Overall, BW was more responsive to tested treatment than DW, at all studied levels. Tested PF5-based formulation represents an interesting resistance inducer and could therefore be used as an alternative to chemical control of septoria disease in susceptible DW and BW cultivars, when applied in a preventive manner at the right concentration, and appropriate developmental stage. Key words: Mycosphaerella graminicola, oligosaccharides, infection, defence, wheat species

84


SCREENING FOR INTERESTING ELICITORS TO PROTECT WHEAT AGAINST ZYMOSEPTORIA TRITICI G. LE MIRE1, A. SIAH2, M. DELEU3, M. ONGENA4, M-L. FAUCONNIER5 and M.H. JIJAKLI1 1

Integrated and Urban Plant Pathology, Gembloux Agro-Bio Tech, ULg Passage des Déportés, 2, BE-5030 Gembloux, Belgium 2 BioGAP, Agricultural Institute of Lille (ISA Group) 48 Boulevard Vauban, FR-59046 Lille Cedex, France. 3 Industrial and Biological Chemistry, Gembloux Agro-Bio Tech, ULg 4 Bio-Industries, Gembloux Agro-Bio Tech, ULg 5 General and Organic Chemistry, Gembloux Agro-Bio Tech, ULg Passage des Déportés 2, BE-5030 Gembloux, Belgium

Plants face an array of biotic and abiotic stresses in their environment, making it necessary to use various chemical inputs to maintain satisfactory yield. Today, conventional agriculture is evolving towards more sustainable practices, out of respect for human health and the environment. Elicitors are considered as promising biological control tools and draw major interest in IPM strategies. These plant-immunity triggering compounds, also called “stimulators of plant natural defences”, induce a general and systemic resistance in the plant to various diseases. Although numerous elicitors have already been identified and some of them reached the market since the late 1970s, further investigations are still required to better understand the mode of action of these molecules in the plant and ensure a consistent efficiency under various field conditions. Few elicitors have yet been successfully tested and formulated to protect crop plants such as wheat, which is cultivated over large areas in Europe. This study focuses on the screening of ten potential elicitor products of various origins and structures to protect winter wheat against the fungal pathogen Zymoseptoria tritici. Greenhouse trials were carried out to measure the ability of the different products to reduce disease foliar symptoms (necrosis, chlorosis and pycnidia). In addition, the phytotoxicity and biocide activities of these products were evaluated under greenhouse and laboratory conditions, respectively. The corresponding results will be presented and discussed with the perspective to choose the best elicitor candidates and to undertake investigations on the signalling pathway and the influence of environmental parameters on the elicitation capacity. Key words: Wheat, elicitor, Zymoseptoria tritici, disease severity, greenhouse

85


ASCORBIC ACID CONTROL MYCOSPHAERELLA GRAMINICOLA IN WHEAT THROUGH DIRECT EFFECT ON THE PATHOGEN AND INDIRECT ACTION ON THE PLANT L. SOMAI-JEMMALI1, M. MAGNIN-ROBERT3, B. RANDOUX3, A. SIAH2, B. TISSERANT3, P. HALAMA2, Ph. REIGNAULT3 and W. HAMADA1,4 1

Laboratoire Génétique et Amélioration des Plantes, Institut National Agronomique de Tunis 43 Avenue Charles Nicolle, 1082 Tunis, Tunisie 2 Equipe Agriculture, Institut Supérieur d’Agriculture 48 Boulevard Vauban, FR-59046 Lille Cedex, France. 3 Equipe Interactions Plantes-Champignons et Remédiation Unité de Chimie Environnementale et Interactions sur le Vivant - EA 4492 50, rue Ferdinand Buisson, C.S. 80699, FR-62228 Calais Cedex, France 4 Ecole Supérieure d'Agriculture du Kef, 7119 Le Kef, Tunisia

Septoria tritici blotch (STB) caused by Mycosphaerella graminicola is one of the most devastating foliar diseases on wheat. Due to the emergence of fungicide-resistant M. graminicola strains and in an effort to reduce the impact of pesticides on the environment, considerable interest has been devoted to sustainable alternative strategies. The use of natural products to control pathogenic fungi, especially through a defence-activating effect on the host, could be considered. Acid ascorbic (AA), a compound synthetized by plants and most animals, has now gained significant place in biological science, mainly due to its cellular antioxidant properties. This study has the following objectives: (i) to assess the protective effect of AA-based product on two M. graminicola sensitive-wheat species (Triticum durum and T. aestivum) and (ii) to investigate the mechanisms involved in the wheat protection. Therefore, the foliar application of a formulated AA-based product (50 mg L-1) on 3-week-old wheat plants reduced the infection level by more than 75% for both bread (BW) and durum (DW) wheat species. In vitro experiments revealed that AA exhibited high inhibition of spore germination (50 mg L-1) and hyphal growth (16 mg L-1) for both fungal strains. Used as preventive foliar spray on wheat leaves, the analysis of AA effect by microscopic observations revealed that AA directly inhibited spore germination, hyphal growth, leaf penetration, substomatal colonization and eventually sporulation. Moreover, AA treatment also decreased fungal cell wall degrading enzyme activities, pathogenicity determinants of M. graminicola. In addition to these direct effects, AA reveals an interesting ability to induce wheat defences reactions. In non-inoculated context, AA-eliciting effect was observed on various stress responses through (i) stimulation of enzymatic activities such as lipoxygenase, peroxydase and catalase and (ii) transcripts accumulation of genes encoding for pathogenesis-related (PR) proteins (chitinase class IV, peroxidase). In inoculated condition, important accumulation of H2O2 and phenolic compounds were observed at the site of penetration in AA-treated leaves in comparison to the control. In parallel, AA treatment seems to impact phenylpropanoid pathway, through the stimulation of phenylalanine ammonia lyase activity 2 days after inoculation for BW and 5 days for DW, respectively. Two days after M. graminicola inoculation, while the transcript analysis revealed a repression of LOX gene in control leaves of both cultivars, a general induction was noticed after AA treatment. These results suggest that, in our conditions, AA presents an antifungal activity and triggers several plant defences in wheat leading to pathogen control. Key words: Septoria tritici, Ascorbic acid, antifungal activity, plant defence, PR proteins.

86


BIOCONTROL PROPERTIES OF ORFAMIDE-TYPE LIPOPEPTIDES PRODUCED BY FLUORESCENT PSEUDOMONADS AGAINST THE FUNGAL PLANT PATHOGENS MAGNAPORTHE ORYZAE AND

RHIZOCTONIA SOLANI Z. MA1, N. GEUDENS2, N. PHUONG KIEU1, D. SINNAEVE2, J.C. MARTINS2, M. ONGENA3 and M. HÖFTE1 1

Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium 2 NMR and Structure Analysis Unit, Department of Organic and Macromolecular Chemistry Ghent University, Ghent, Belgium 3 Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium Corresponding author E-mail: [email protected]

Soil-derived Pseudomonas species are among the most intensively studied candidates which could be developed as biological control agents. These plant beneficial bacteria can survive and reach a relatively high population in the rhizosphere, and, contribute to plant growth development, diseases suppression on roots, and even indirectly reduce the incidence of foliar diseases of plants. Bio surfactants produced by plant beneficial bacteria could play roles in biofilm formation, root colonization, bacteria motility and other potential biocontrol traits. Pseudomonas sp. CMR5c is a cocoyam rhizosphere-derived bacterium and significantly protects cocoyam against the root rot pathogen Pythium myriotylum. Genome mining of draft genome sequences of Pseudomonas sp. CMR5c suggested the presence of nonribosomal peptide synthases which could synthesize lipopeptide type bio surfactants. In a further study, lipopeptides produced by Pseudomonas sp. CMR5c were purified by semipreparative high performance liquid chromatography system, the structure of purified compounds was determined by liquid chromatography-mass spectrometry combined with nuclear magnetic resonance analysis, and these compounds were finally identified as orfamides. The orfamide-synthases from related orfamide producing Pseudomonas strains such as P. protegens Pf-5 and P. protegens CHA0 were compared by bioinformatics analysis and biochemical analysis. Pseudomonas sp. CMR5c mainly produces orfamide B, while Pf-5 and CHA0 mainly produce orfamide A. The potential antibiotic activity of purified orfamide B was evaluated against the rice blast pathogen Magnaporthe oryzae and the soilborne pathogen Rhizoctonia solani by paper disc-agar diffusion assay. Purified orfamide did not show any antagonistic activities against Magnaporthe oryzae, but caused intensive branching of Rhizoctonia solani hyphae. Further biological control assays on rice plants showed a reduced incidence of Magnaporthe oryzae when purified orfamide B and fungal spores were applied together. We are currently investigating whether orfamide A has similar activities. Collectively, orfamide family lipopeptides could be developed as environmental friendly biopesticides and could be utilized in organic food production and sustainable agriculture processes. Key words: Fluorescent pseudomonads, non-ribosomal peptide synthases, orfamides, biological control, fungal plant pathogens

87

Posters - Special session: EMERGING PESTS AND DISEASES

88

89

Posters - Special session Emerging pests and diseases S01

MONILINIA FRUCTICOLA - EMERGING PATHOGEN ON STONE FRUIT IN SERBIA J. HRUSTIĆ and B. TANOVIĆ Laboratory of Applied Phytopathology Institute of Pesticides and Environmental Protection Belgrade, Serbia

Brown rot, caused by species of the genus Monilinia, is one of the most economically important fungal diseases of stone fruit with a worldwide distribution. Two species of this genus, Monilinia laxa and M. fructigena, are widely distributed in Europe, as well as in Serbia. Regardless the quarantine status of M. fructicola in the EPPO region, it has been detected in many European countries since its first discovery in France in 2001. In Serbia, M. fructicola was firstly recorded on stored apple and nectarine fruit in 2011. In order to determine population structure of brown rot causing fungi in stone fruit in Serbia, a fiveyear survey was conducted. During 2010-2014 period, over 500 samples of stone fruit with symptoms of twig blight and fruit rot were collected. The pathogen was isolated using standard phytopathological methods and identified according to pathogenic, morphological and ecological properties. Identification of the isolates was confirmed by Multiplex PCR using species’ specific primers. Based on pathogenic, morphological and ecological characteristics, and on Multiplex PCR results, three species of the genus Monilinia (M. laxa, M. fructigena and M. fructicola) were identified. M. laxa was by far the most prevalent species, detected in over 90% of all analyzed samples. In the first year M. fructicola was not found despite intensive survey. During the period 2011-2012, M. fructicola was a minor pathogen detected in three locally-produced nectarine fruit that were found on green markets. However, the presence of the pathogen in the claimed orchards was not confirmed despite a high number of collected samples. In 2013, M. fructicola was detected in peach, nectarine, apricot and plum orchards, while in 2014 M. fructicola was isolated from cherries. The confirmed presence of M. fructicola in Serbia, as well as its apparent increased detection during the survey, indicates that a change in the population structure of these pathogens may be occurring. This change could have an important impact on the disease management making it more complex. Therefore, future population structure changes, especially the spread of M. fructicola, should be managed with special attention and in accordance with all available quarantine and control measures. This research was supported by grant III46008 of the Ministry of Education, Science and Technical Development of the Republic of Serbia. Key words: brown rot, population structure, quarantine

90


DEVELOPMENT OF IPM-TOOLS FOR THE CONTROL OF CEREAL LEAF BEETLE AND APHIDS IN GRAINS E. VAN DE VIJVER, G. SMAGGHE, B. DE BAETS and G. HAESAERT Faculty Bioscience Engineering, Ghent University Coupure links 653, BE-9000 Gent, Belgium

That insects reduce yield of cereals has been proved before by a large number of researchers all over the world. The cereal leaf beetles Oulema melanopus and the Oulema gallaeciana (Coleoptera: Chrysomelidae) are common plague insects in small grain cereals in the northern half round. Knowledge of optimal timing for chemical pesticide-application is absent in Europe, as well as selective pesticides approved in Flanders for the control of CLB (Cereal Leaf Beetle). Controlling grain aphids (Metopolophium dirhodium, Rhopalsiphum padi and Sitobion avenae; Hemiptera: Aphididae) can interfere with the chemical control of the CLB. For the control of these leaf beetles, farmers often use broad-spectrum pesticides (pyrethrums such as lambda-cyhalothrin) in tank-mixes with another application (fungicides/nitrogen). As the – arbitrary- application is often done with wrong timing, they kill all present insects in the crop, including natural enemies. This can cause an even faster regrowth of the aphid populations and therefore the need for a second application. With the introduction of SUD 2009/128/EC by the European Parliament, January 2014, farmers are obligated (art. 14) to use a more integrated way to control the pests in their crops. One way to accomplish this is using selective pesticides to keep the natural enemies alive and let these “Farmers’ Friends” help controlling the plague. In a 4 year-research-program, the aim of this study is to develop a model that predicts optimal timing of application, as well as give an advice to the farmer what selective pesticide to use. This model would be based on data from numerous fields that lay all over Flanders, Belgium. These fields are chosen based on variation in region, rotation, border management, e.g. . During growth season, parameters as population growth of the CLB, grain aphids and natural enemies of both plagues as well as the controlling effect of the natural enemies will be measured. How these parameters interact with other variables such as weather data and other field specific characteristics will be implemented into the model as well. Lastly the correlation between population density and yield will be tested. This provides the ability to set specific economic thresholds. Key words: IPM, CLB, aphids, natural enemies

91


92

93

Posters - Session 1 NEMATOLOGY

94

95

Posters - Session 1 Nematology N01

SCREENING FOR RESISTANCE TO MELOIDOGYNE JAVANICA IN COMMON BEAN C.L. OLIVEIRA, M.S. OLIVEIRA, V.P. CAMPOS, G.L. REIS, R. FONSECA, N.S. OLIVEIRA, L.S. CASSETARI and L.A.A. GOMES Agricultural Department Universidade Federal de Lavras Lavras, MG, Brazil

In the sense of the importance of the development of resistant bean genotypes against tropical root knot nematodes, we conducted a study to characterize the reaction of commercial and breeding lines of common bean against the root knot nematode Meloidogyne javanica. The assay was in a greenhouse using 54 bean genotypes and one susceptible tomato cultivar (Santa Clara). Three seeds of each bean genotype were sowed in three litre pots alongside with 30 days tomato seedlings which were transplanted into the pots. A randomized block design with three replications and two plant pots per plot was used. Fifteen days after sowing, the soil around the plants was infested with 10.000 M. javanica eggs and the plants were grown until 60 days after sowing, when they were harvested and evaluated for root weight, total number of eggs, and number of eggs per gram of root. The results indicated significant differences between genotypes for root weight, total eggs and eggs per gram of root (P