www.ijaaer.com International Journal of Agricultural and Environmental Research
ISSN: 2414-8245
POPULATION DYNAMICS OF CEREAL APHIDS IN WHEAT CROP AT DISTRICT SWABI ASAD ALI1 AND HIRAD ALI2 1
Dept: of Agriculture, Abdul Wali Khan University Mardan 2 Department of Zoology, University of Swabi Corresponding author E.mail:
[email protected]
Abstract Being serious threats to cereal crops, the estimation of aphid population and its timely control is always a challenge for agriculture scientists. In order to evaluate population dynamics of aphid a survey was conducted in selected areas of district swabi. For population dynamics, number of aphids were recorded on weekly basis using diagonal methods by randomly selected 5 plants from each fields. The findings of the study indicated that aphid attack started in the 1st week of February and increased as the vegetative growth proceeded. Moreover, the aphid population was higher in the 2nd and 3rd week of March and decreased subsequently. Keywords: Aphids, Wheat, Yield and Swabi
1. Introduction Cereal crops have been the backbone of national agriculture for the last few decades, as they are staple food crops being superior to other crops in terms of area under cultivation and source of energy (Farhad et al., 2009). Ensuring sustainable food security by producing more food and at the same time combating poverty and hunger of an exponentially growing population in the coming decades is a major consideration of Pakistani agricultural scientists (Ali et al., 2011). Therefore, exploring ways and means of maintaining or escalating cereal crops productivity without degrading soil health is an important goal in sustaining livelihoods and improving life standard of farmers (Delate and Camberdell, 2004). Wheat was chosen as the trial crops because wheat among cereal crops ranks first worldwide, measured either by cultivated area or production (Jagshoran et al., 2004). According to the Pakistan Bureau of Statistics annual report for 2012-2013, the country produced 25285 t of wheat from an area of 9039 ha in the 2013-2014 and 2527.2 t of maize grain from 1116.6 ha of land in 2013-2014. Wheat has got an evolutionary history parallel to the history of human civilization; as it decides the feast or famine for millions of people even today. Wheat contributes more than 10% of the total agricultural products and 15% of agricultural employment in Pakistan, over 50% share of which comes from small landholding farmers (FAO, 2011). It is highly nutritious as it’s per ISSN: 2414-8245
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67 acre amino acid yield is far exceeding that of animal products (Zong et al., 2008). It attained its premier position due to its unique protein called gluten, responsible for bread making property of wheat flour (Asp et al., 1986). Within these farming systems, the intrinsically low fertility of the soil and increasing prices of chemical fertilizers pose an imminent threat to increasing yields of cereal crops (Shah and Khan, 2003). The need to simultaneously increase yields, decrease production costs, and maintain soil health has therefore become a major challenge for agricultural scientists (Anjum et al., 2011). Although, in Pakistan wheat is grown on a fair percentage of the total cultivated area, it is still struggling hard to become self-sufficient in wheat production. Numerous factors are responsible for the low yield of wheat in Pakistan. Beside, the lack of modern agronomic practices, insect pests play important role in reducing the yield/hectare. Looking at the variation in soil types, cropping patterns, and farmers resources various management practices could be exercised to increase wheat production. Various factors are responsible for low per unit yield of wheat as compared to the wheat yield in advance countries. Regardless of soil types and crop seasons, aphids attack and its control strategies are declared the most responsive factor for wheat disease and low yield (Dong et al., 2006). Aphid also known as plant lice is an importance sucking pest of various field crops, fruits and vegetables (Aheer et al., 2008). In Pakistan, English grain aphid (Sitobion avenae F.), Greenbug (Schizaphis graminum R.) and Bird cherry-oat aphid (Rhopalosiphum padi L.) are important wheat aphid species (Khan and Farmanullah, 2005). Among insect pests, 29 aphid species infest wheat crop (Geza, 2000). Dominant species are the greenbug, Schizaphis graminum (Rondani), bird cherry oat aphid, Rhopalosiphum padi (L.), English grain aphid, Sitobion avenae (Fabricius), Russian wheat aphid, Diuraphis noxia (Mordvilko) and rose-grass aphid, Metopolophium dirhodum (Walker) (Bospucperez & Schotzko, 2000). Aphid species S. avenae, R. padi, and S. graminum are the insect pests of wheat in Pakistan (Shah et al., 2006). Aphids suck sap from leaves and shoots that results in curling, chlorosis, distortion of leaves and hence stunted growth (Kindler et al., 1995; Akhter & Khaliq, 2003). Aphids can cause 35-40% loss directly by sucking sap and 20- 80% indirectly by transmission of fungal and viral diseases (Kiechefer & Gellner, 1992; Rossing et al., 1994). R. padi alone caused yield losses up to 600 kg/ha in wheat (Hallqvist, 1991). Aphids cause direct damage by feeding deeply within the leaf whorl and inject a toxin in the plant which destroy the chloroplast membrane and indirect damage by transmission of several plant viruses (barley yellow dwarf Luteo virus) and by developing molds on their honey dews. Temperature and climate change has potential impacts on plant disease through both the host crop plant and the aphids. Research has shown that host plants such as wheat become more susceptible to aphids attack with increased temperature; but some forage species become more resistant to fungi with increased temperature (Coakley et al., 1999). Late sown wheat crop may be badly damaged by aphids’ attack, if the cool and time-to-time cloudy weather continues till the end of March (Bhambhro, ISSN: 2414-8245
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68 2002). Potential for aphid infestation can be reduced by sowing wheat early in the season (Acreman and Dixon, 1985) to avoid temperature injury. Significantly low aphid infestation on early sown wheat varieties has been reported. It has also been suggested that early maturing varieties would avoid outbreaks of aphids Barabas and Benovsky (1985). Aphid infestation increases on late plantings of wheat and reduces the yield as compared to normal planting due to variation in temperature (Aheer et al., 1993).
2. Material and methods In order to evaluate the effect of aphids attack on cereal crops (Wheat) and the population trend of cereal aphids, field survey was conducted at farmers’ field of selected areas of district Swabi. The selected fields were visited at one week interval during the growing season (2014-2015). The fields were randomly selected at different locations such as Lahor, Jaganth, Yaqoobi, Sodher and Yar-Hussain. Aphids samples from five randomly selected wheat tillers were collected irrespective of the variety grown on each location. Samples spots were randomly spaced along a diagonal across the field and were not closer than 10 feet from the field edge. Population build-up started in the month of December-January, so the date collection was initiated from the end of December and continued till the crop maturity (Mid of May).
3. Results and discussion Mean average population of aphid plant-1: During the course of the study, aphids population in wheat crop was observed in the month of February and showed increasing trend as the plant growth proceeded. Rapid increase was observed at the month of February however, higher aphid population was observed in the month of March. Generally, it was found that aphids population was increasing from start of February till march end and after that decreasing trend was noted in aphids population (Fig. 6). Location 1: Mean number of Aphids in Lahore: The aphids population first increase and then decreased from first to 3rd week of February. Initially lower aphids population was observed (first week of February), then increased from 10 to 20 aphids plant-1 however, it decreased to 16 aphids plant-1 in 3rd week of February. Interestingly, rapid increase in aphid population was observed from 4th week of February to first week of March (30 aphid plant-1). Moreover, it was further increased to 35 aphids plant-1 in the second week of March after that rapid decrees in aphids population was observed till the end of March and almost disappeared in the month of April. (Fig. 1)
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Fig. 1. Mean number of aphids in Lahore Location 2: Mean number of Aphids in Jaganath: Data regarding the number of aphids plant-1 in Jaganath are presented in Figure 2. The figure showed similar trend in aphids population with the passage of time as it was observed in Lahore. The figure illustrated lower aphid population in the first week of February with increasing trend till the 2nd week of March (increased from 10 aphids plant-1 to 45 aphids plant-1). Gradual decrease in aphids population was observed from the 3rd week of March till the end of March and during April no or very less number of aphids were collected from the sample area.
Fig. 2. Mean number of Aphids in Jaganath Location 3: Mean number of Aphids in Yaqubi: Data concerning aphid population on wheat crop in Yaqubi are shown in Figure 3. The figure indicated that aphids population increased as the vegetative growth proceded. During the 1st and 3rd week of February the aphids population was negligible.. The figure ISSN: 2414-8245
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70 showed that in the 4th week of February the aphids population decreased. Form the 1st to 3rd week of March the aphids population suddenly increased (from 16 aphids plant-1 to 41 aphids plant-1) and after that the population fell down and they become disappeared to the mid-April.
Fig. 3. Mean number of Aphids in Yaqubi Location 4: Mean number of Aphids in Sodher: The population trends of aphids in sodher are illustrated in Figure 4. The figure revealed that aphids population was very low at the 1st week of February, however; during 2nd and 3rd week of February aphid population was raised to 25-26 aphids plant-1 and fell down in the 4th week of February up to 21 aphids plant-1. The figure showed that in the 1st week of March the number of aphids plant-1 were increased up to 33 aphids plant-1 and during 3rd and 4th week of March their population were at equilibrium state as shown in the Figure 4. From the 4th week of March to midApril aphids population fell down and finally become disappeared.
Fig. 4. Mean number of Aphids in Sodher ISSN: 2414-8245
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71 Location 5: Mean number of Aphids in Yarhussain: Date regarding aphids population in Yarhussain are shown in Figure 5. It was found that aphid population increased from 1st to 3rd week of February from 20 aphids plant-1 to 26 aphids plant-1 respectively. Furthermore, it decreased to 18 aphids plant-1 in the 4th week of February. Rapid increase in aphid population was observed in the 1st and 3rd week of March as compared to 2nd and 4th week of march.
Fig. 5. Mean number of Aphids in Yarhussain
Fig. 6. Mean number of Aphids in all five areas of District Swabi 3.1 DISCUSSION The present reasrch was designed to evaluate the effect of aphids population dynamics on wheat crop at different growth stages. Data were recorded from the start of February till the end of April at different locations of District Swabi (Lahore, Jaganath, Yaqubi, Sodher and Yarhussain). Many research workers have studied the resistant ability of plants against their insect pests. Published information reveals that aphids are serious pests of wheat crop (EL Bouhssini et al., 2000). In the present study, the increase in population was gradual from vegetative growth stage (sowing till mid march) to inflorescence (Reproductive stage). Similar results were also observed by ISSN: 2414-8245
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72 Hussein (1993) who concluded that aphid's population in wheat crop was lower during the month of January and February whoever, it increased till mid March. According to him a maximum abundance of each aphid species occurred at the beginning of flowering period or booting stage (Mid March), after which the population fell rapidly (Mid April). These results in are inline with the findings of current research. Rustamani et al., (1999) observed that the infestation of aphids appeared during the 3rd week of February on all wheat varieties. The increase in population was gradual during vegetative growth stage but the aphids multiplied rapidly during the reproductive stage. The variation in the aphid density tiller-1 of wheat in different varieties could be the resistance response of these varieties to aphids attack. Aheer et al., (2007) found that aphid population decreased when maximum temperature and minimum temperature reached to the optimum limits i.e., 24.30°C and 9.57°C. Our results supports this statment as aphids population lower at the start of February (temperature < 10C0) and end of March or start of April (temprature > 24C0). It was also noted that the attack of aphids was maximum during the end February or start of March when the temperature was in the aphids favoring range. Temperature and humidity plays an important role in the population build up of aphids. There are numerous factors which affect the speedy increase and decrease of aphids population (Aheer et al., 2007). Both the physical and biological factors are much vital causing the variations in the densities of aphid population (Naeem, 1996). Findings of (Aslam et al., 2005; Aheer et al., 2008) that, fluctuation in temperature starts to enhance their population was in accordance to above mentioned results. Declined Rh% improves helpful in the process of population growth. (Srivastava et al., 1995) concludes about positive effect of rainfall and increased temperature causes reduction in abundance of aphid population. (Weins et al., 2008) reported negative correlation of rainfall with aphid population in Wheat. Reason may be the continuous change in climatic conditions.
4. Conclusions It was concluded that aphids population was lower at the start of february in all locations. The aphids population increased from mid of February till the end of March and decreased after that at all locations. Aphid dynamics were largely dependent on temperature and relative humidity, however aphid population was not significantly correlated with rainfall. Aphids population could be minimized by early sowing of wheat also use of resistant cultivars and chemical treatment are helpful in controlling wheat loses due to aphid infestation. The result shows that the use of indiscriminate insecticides and pesticides caused more mortality to wheat insects. Insecticides might have adverse effect on natural enemies, however, NeemAzal T/S treatments is favorable to natural enemies. The use of insecticides are harmful for natural enemies and due to decrease in the population of natural enemies the aphids population will reach to the economic threshold level and cause serious damage to the wheat crop. ISSN: 2414-8245
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5. References Acreman, T.M. and A.F. Dixon. 1985. Development patterns in the wheat and resistant to cereal aphids. J. Crop Protec., 4: 322-328. Adams, M.L., E. Lombi, F.J. Zhao and S.P. McGrath. 2002. Evidence of low selenium concentration in UK bread making wheat grain. J. Sci. and Food Agr., 82:1160-1165. Adisu, B., P. Stary, B. Freier and C. Buttner. 2002. Aphidius colemani Vier. (Hymenoptera: Braconidae) detected in cereal fields in Germany. Anzeiger Schadlingskunde. J. Pest Sci., 75: 89-94. Aheer, G.M., Haq, I., Ulfat, M., Ahmad, K.J. and Ali, A. 1993a. Effect of sowing dates on aphids and grain yield in wheat. J. Agri. Res., 31: 7579. Aheer, G.M., I. Haq, K.J. Ahmad and A. Ali. 1993b. Varietal resistance and sowing date effect on aphid density and wheat yield. J. Agric. Res., 31: 313-317. Aheer, G.M., M. Munir and A. Ali. 2007. Impact of weather factors on population of wheat aphids at Mandi Baha-ud-Din district. J. Agric. Res., 45: 61-66. Aheer, G.M., A. Ali and M. Ahmad. 2008. Abiotic factors effect on population fluctuation of alate aphids in wheat. J. Agri. Res., 46: 367-371. Ahmad, F., 2009. Food security in Pakistan. Pak. J. Agri. Sci., 46: 83-89. Ahmad, R and A.S. Shaikh. 2003. Common weed of wheat and their control. Pak. J. Water Res., 7: 73-76. Akhtar, L.H., M. Hussain, R.M. Iqbal, M. Amer and A.H. Tariq. 2010. Losses in grain yield caused by Russian wheat aphid Diuraphis noxia (Mordviko). Sarhad J. Agri., 26: 625-629. Akhtar, I.H and A. Khaliq. 2003. Impact of plant phenology and Coccinellid predators on the population dynamic of rose aphid Macrosiphum rosaeiformis Das (Aphididae: Homoptera) on rose. PI. Sci., 2: 119122. Akhtar, N and Y. Mujahid. 2006. Pattern of resistance to Schizaphis gramimum (Rondani) among rain fed national uniform wheat varieties. Pak. J. Zoo., 38: 153-157. Anonymous. 2010. Economic survey of Pakistan. Ministry of Food, Agriculture Federal Bureau of Statistics, Islamabad, Pakistan 22pp. Anwar, J., M.A. Ali, M. Hussain, M.A. Khan, M. Zulkiffal and M. Abdullah. 2009. Assessment of yield criteria in bread wheat through correlation and path analysis. J. Ani. and Plants Sci., 19: 185-188. Asin, L and X. Pons. 2001. Effect of high temperature on the growth and reproduction of corn aphids (Homoptera: Aphididae) and implication for their population dynamics on the northeastern Iberian Peninsula. Enviro. Ento., 30: 1127-1134. Aslam, M., M. Razaq, W. Akhter, M. Faheem and F. Ahmad. 2005. Effect of sowing date of wheat on aphid (Schizaphis gramium R.) population. Pak. J. Ento., 27: 79-82. ISSN: 2414-8245 Ali et al., (2015)
74 Atwal, A.S. 1976. Agriculture pest of India and Southeast Asia. Kalyani Publisher Delhi. 502 pp. Blackman, R.L. and Eastop, V.F. 1984. Aphids of world’s crops an identification and information guide. J. Econo. Ento., 81: 1383-1388. Das, B. 1913. The aphidiodea of Lahore. Mem. Indian. Mus, 6: 138-274. El-Gizawy, N.K.B. 2009. Effect of planting date and fertilizer application on yield of wheat under no till system. World J. Agri. Sci., 5: 777-783. Fuentes-Contreras E., Pell, J.K and Niemeyer, H.M. 1998. Influenced of plant resistance at the third trophic level: interactions between parasitoids and entomopathogenic fungi of cereal aphids. Oecologia., 117: 426432. Gair, R.J.R.E., Jenkins and E. Lester. 1983. Wheat pest Cereal pest and Diseases. (3rd Edition). Farming press Ltd. UK. pp-54-80, Neb Guidecereal Aphids, G96-1284-A. Hallqvist, H. 1991. Bekampningstosklar for havrebladlus (Rhopalsiphum padi) I varsad-resultat fran Mellansvergie. In: 32nd Swedish Crop Protection Conference. Swedish university of agricultural science, Uppsala, pp. 197-205. Hamid, S. 1976. Natural enemies of graminicolous aphids (Annual Report). Common wealth Biological Control Institute, 1976. pp 61. Hashim, A.A., Hussain, M.M. and Ulfat, M. 1983. Insect pest complex of wheat crop. Pakistan Journal of Zoology, 15: 169-176. Havlickova, H. and Holubec. V. 1999. Abundance of cereal aphids (Hemiptera: Aphididae) within wild Triticum and Aegilops spp., and cultivated wheat. Plant Protec. Sci., 35: 67-70. Havlickova, H. 1997a. Differences of level of tolerance to cereal aphids in winter wheat cultivars. Rostlinna Vyroba. 43: 593-596. Helmi, A. and Rashwan, R. 2013. Effect of wheat cultivars and sown dates on aphid infestation in Egypt. Munis Entomology and Zoology., 8: 825-830. Hesler, L.S., Kieckhefer, R.W. and Evenson, P.D. 1999. Abundance of cereal aphids (Homoptera: Aphididae) and their predators in spring wheatalfalfa intercrops under different crop management intensities. Northern Grain Insect Research Laboratory. USDA-ARS. 2913 Medary. Great-Lakes Entomologist., 33: 17-31. Hussein, I.A.A. 1993. Abundance dynamics of cereals aphids (Homoptera: Aphididae) and their natural antagonists on different wheat types in Deir Ezzor (Syrian Arab Rep.). Arch. Phytopathology and Plant Protection., 28: 439-445. Irshad, M. 2001. Distribution host ecology and biotic potential of Coccinellids of Pakistan. Pak. J. Bio. Sci., 14: 1259-1263. Irshad, M., and Khan, M.R. 2005. Insects’ pests of plants and their parasitoids, predators and pathogens in Pakistan. PIPS Ltd. 72 pp. Istvan, H. 2006. The main elements of sustainable food chain management. Cereal Res. Community., 34: 1779-1793. ISSN: 2414-8245
Ali et al., (2015)
75 Khan, S.A. and Farmanullah, 2005. Studies on the aphid distribution pattern and their natural enemies in wheat and maize crop. Ph.D. thesis, Department of Plant Protection, Agricultural University Peshawar, Pakistan, 61-62. Khan, K. A., Khan, M. A., Tahir, M. H., Afzal, M., Khaliq, A., Khan, Y. S. and Raza, I. 2011. Effect of wheat cultivars on aphids and their predator population. Afri. J. Biotech., 10: 18399-18402. Khattak, M.K., Riazuddin and M. Anayatullah. 2007. Population dynamics of aphids (Aphididae: Homoptera) on different wheat cultivators to aphid in respect of yield and yield related parameters. Pak. J. Zool., 39: 109115. Kiechefer, R.W. 1975. Field population of cereal aphids in South Dakota spring grains. J. Eco. Ento., 68: 161-164. Kiechefer, R.W., Kantack, B.H. 1980. Losses in yield in spring wheat in South Dakota. J. Econo. Ento., 73: 582-585. Kiechefer, R.W and Gellener, J.L. 1992. Yield losses in winter caused by low density cereal aphid’s population. Argon. J., 84: 180-183. Kindler, S.D., Springer, T.L. and Jensen, K.B.L. 1995. Detection and characterization of the mechanisms of resistance to Russian wheat aphid (Homoptera: Aphididae) in tall wheat grass. J. Eco. Ento., 88: 1503-1509. Leather, S.R., Walters, K.F.A. and Dixon, A.F.G. 1989. Factors determining the pest status of the bird cherry-oat aphid, Rhopalosiphum padi L. (Hemiptera: Aphididae), in Europe: a study and review. Bulletin of Ento. Res., 79: 345-360. Lee, G., Stevens, D.J., Stokes, S. and Wratten, S.D. (1981) Duration of cereal aphid populations and the effect on wheat yield and bread making quality. Ann. Appl. Biol. 98: 169-178. Lefrory, H.M. 1909. Indian insect life. Thacker Spink, Calcutta. Lowe, H.J.B. 1987. Breading for resistance to insect. Wheat breading, (F.G.H. Lupton, ed.). Chapman and Hall Ltd., UK: 423-454. Manna, S.H. 2000. Cereal aphids on wheat in New Valley: Natural enemies’ seasonal activity of alate forms and susceptibility of certain varieties to natural infections. Assiut J. Agri. Sci., 31: 287-297 Migui, S.M. and Lamb, R.J. 2003. Patterns of resistance to three cereal aphids among wheats in the genus Triticum (Poaceae). Bulletin. Ento. Res., 93: 323-333. Mohyuddin, R.L. 1981. A review of biological control in Pakistan. Congress of Zoology, 2: 31-79. Nawaz, 2000. Insect pest of wheat and effect of fertilizer (NPK) on aphid’s population M.Sc. Thesis presented to the department of Entomology Agricultural University Peshawar. Naylor, A.I. and Erlich, P. 1997. Natural pests control service and agriculture. In: Nature’s Services; societal dependence on natural ecosystems (ed. G.C. Daily). Island Press, Washington DC, pp. 151-174. ISSN: 2414-8245
Ali et al., (2015)
76 Oakley, J.N. and Walters, K.F.A. 1994. A field evaluation of different criteria for determining the need to treat winter wheat against the grain aphid (Sitobion avenae) and rose grain aphid (Metopolophium dirhodum). Ann. Appl. Biol. 124: 195-211. Ostman, O., Ekbom, B. and Bengtsson, J. 2003. Yield increase attribute to aphid predation by ground-living polyphagous natural enemies in spring barley in Sweden. Eco. Econo., 45: 149-158. Pimentel, D. (1997) Techniques for reducing pesticide use economic and environmental benefits. Wiley, Chichester, UK. Pons and Lloveras, 1999. Aphids on ornamental shrubs and trees in an urban area of the Catalan coast: Bases for an IPM programme. In: Aphids in a New Millenium. J.C. Simon, C.A. Dedryver, C. Risp and M. hulle (eds) Editions INRA. Pons, X., Albajes, R., Avilla, J., Sarasua, M.J., Artidues, M. and Eizaguirre, M. 1989 Spring population development of cereals aphids on durum wheat in Llcida, NE of Spain. J. App. Ento., 107: 203-210. Rafi, M.A., Irshad, M. and Inayatullah, M. 2005. Predatory ladybird beetles of Pakistan. National insect Museum and Insect Pest Informatics, IPM Programme. Robani Press, Islamabad, Pakistan, 105 pp.. Riazuddin, Anayatullah, M. and Khattak, M.K. 2004. Screening resistant wheat lines against aphids. Pak. J. Ento., 26: 13-18. Rossing, W.A.H., Daaman, R.A. and Jansen, M.J.W. 1994. Uncertainty analysis applied to supervised control of aphids and brown rust in winter wheat. Part2. Relative importance of different compound of uncertainty. Agris. Sys. 44: 449-460. Schotzko, D.J. and Bosque-Perez, N.A. 2000. Seasonal dynamics of cereal aphids on Russian wheat aphid (Homoptera: Aphididae) susceptible and resistant wheats. J. Eco. Ent., 93: 975-981. Triplehorn, C.A., and Johnson, N.F. 2005. Introduction to the study of insects. 7th Edition. Thomson Books 10 Davis Drive Belmont, Ca 94002 USA. Wains, M.S., Aziz-ur-Rehman., Latif, M. and Hussain, M. 2008. Aphid dynamics in wheat as affected by weather and crop planting time. J. Agri. Res., 46: 361-366. Winston, M. 1997. Nature wars: People vs. pests. Harvard University Press, UK. Zeb, Q. Badshah, H. Ali, R.A. Shah and M. Rehman, 2011. Population of aphids on different varieties/lines of wheat and their effect on yield and thousands grain weight. Sarhad J. Agri., 27: 443-445. Zia, M.A., Aheer, G.M., Mumtaz M.K. and Ahmad, K.J. 1999. Field screening of sixteen advanced line of wheat for resistance to aphids (Homoptera: Aphididae). Pak.J. Ento., 21: 95-97.
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