Soil and crop management

Contents GENETIC EVALUATION AND UTILIZATION Disease resistance 3 Characterizing adult plant resistance to bacterial blight (BB) 6 Performance of HKRl0l under bacterial blight (BB) stress Insect 7 7 7 8

resistance Reaction of rice cultivars to pink stem borer (PSB) Genetics of resistance to whitebacked planthopper (WBPH) in two rices Promising gall midge (GM) resistant rices with short to medium duration Reaction of yellow stem borer (YSB) resistant accessions to other rice pests

Adverse soils tolerance 8 Tolerance for iron deficiency in rice

PEST CONTROL AND MANAGEMENT Diseases 9 Effect of planting date on rice tungro virus (RTV) infection 9 A new rice virus disease in India 10 Rice yield loss to sheath blight (ShB) 10 Yield loss to bacterial blight (BB) in central Thailand 11 Bacteriophage strain of Xanthomonas campestris pv. oryzae from parts of Thailand 12 Nitrogen fertilization and sheath rot (SR) development in rice 13 Reaction to rice tungro virus (RTV) complex as influenced by insect pressure 13 Evaluation of National Screening Nursery (NSN) and International Rice Observational Nursery (IRON) trialsfor bacterial blight (BB) and stem rot (SR) resistance Insects 14 Inheritance of virulence of the North Sumatra population of the brown planthopper (BPH) on IR42 15 Possible genetic isolation between the Leersia and rice brown planthopper (BPH) 15 Monitoring brown planthopper (BPH) biotypes by rice garden in North Sumatra 16 Relationship between biochemical characteristics of rice and establishment of yellow stem borer (YSB) larvae

16 17 17 18 19 19 20 20 20 21 21

Inhibitory effects of insecticides on entomogenous fungi Metarrhizium anisopliae and beauveria bassiana Influence of flooding, fertilizer, and plant spacing on insect pest incidence Effect of organophosphatic insecticides on the yellow stem borer (YSB) eggs and parasites Insect pests of rice in the Sikkim Hills Tabanus (Diptera: Tabanidae) eggs, an alternative host of rice stem borer (SB) egg parasite Telenomus dignus ( Hymenoptera:Scelionidae ) Chironomid, corixid, and ostracod pests of irrigated rice seedling roots Pathogenicity of Beauveria bassiana on brown planthopper (BPH), whitebacked planthopper (WBPH), and green leafhopper (GLH) Leaffolder (LF) outbreak in Haryana, India Cryptoblabes gnidiella, a fern-feeding caterpillar, and its parasite Wet season population fluctuation of whitebacked planthopper (WBPH) in West Java Parasite complex of yellow stem borer (YSB)

Weeds 21 Effect of time of herbicide application on rices of different durations Other pests 22 Influence of rate and time of carbofuran application to control root-knot nematodes in upland rice 23 Entomostracan crustaceans inhabiting rice fields

SOIL AND CROP MANAGEMENT 23 24 25 25 26 26

Residual effects of straw, lime, and manganese dioxide amendments on the chemical kinetics of a flooded iron-toxic soil Response of rice to nitrogen, phosphorus, and zinc in sodic soil Effect of blue green algae (BGA) on rice yield at different locations and residual effect on gram Yield response of upland rice to NPK fertilization with burned rice husk Effect of different nitrogen applications on rice grain yield Effect of bio, organic, and chemical fertilizers on rice grain yield

RICE-BASED CROPPING SYSTEMS 27

Groundnut varieties for summer rice fallows

Guidelines and Style for IRRN Contributors Articles for publication in the International Rice Research Newsletter (IRRN) should observe the following guidelines and style. Guidelines • Contributions should not exceed two pages of double-spaced typewritten text. Two figures (graphs, tables, or photos) may accompany each article. The editor will return articles that exceed space limitations. • Contributions should be based on results of research on rice or on cropping patterns involving rice. • Appropriate statistical analyses should be done. • Announcements of the release of new rice varieties are encouraged. • Pest survey data should be quantified. Give infection percentage, degree of severity, etc. Style • For measurements, use the International System. Avoid national units of measure (cavan, rai, etc.). • Abbreviate names of standard units of measure when they follow a number. For example: 20 kg/ha, 2 h/d. • Express yield data in tonnes per hectare (t/ha). With small-scale studies, use grams per pot (g/ pot) or g/row. • Express time, money, and common measures in number, even when the amount is less than 10. For example: 8 min, $2, 3 kg/ha, 2-wk intervals. • Write out numbers below 10 except in a series containing 10 or higher numbers. For example: six parts, seven tractors, four varieties. But There were 4 plots in India, 8 in Thailand, and 12 in Indonesia. • Write out numbers that start sentences. For example: Sixty insects were put in each cage. Seventy-five percent of the yield increase is attributed to fertilizer. • Place the name or denotation of chemicals or other measured materials near the unit of measure. For example: 60 kg N/ ha, not 60 kg/ ha N; 200 kg seed/ ha, not 200 kg/ ha seed. • Use common names — not trade names — for chemicals. • The US$ is the standard monetary unit in the IRRN. Data in other currencies should be converted to US$. • When using acronyms, spell each out at first mention and put the specific acronym in parentheses. After that, use the acronym throughout the paper. For example: The brown planthopper (BPH) is a well-known insect pest of rice. Three BPH biotypes have been observed in Asia. • Abbreviate names of months to three letters: Jun, Apr, Sep. • Define in the footnote or legend any nonstandard abbreviations or symbols used in a table or figure. • Do not cite references or include a bibliography.

Genetic evaluation and utilization DISEASE RESISTANCE

2.2 at booting. Growth stage did not affect the response of Shi-zu and of susceptible check TN1 to the four races. Reaction patterns of adult plant resistance. Among the cultivars with adult plant resistance, two disease development patterns were observed from the 6th leaf to the flag leaf. Resistance of most cultivars, such as Taichung Sen 5 and Kwang-er-ai 5, increased gradually as the leaf number increased from the 6th to flag leaves. Guai Zhou Magu, however, had a clear-cut susceptible and resistant response (Fig. 1). Leaf response varied. Some cultivars showed resistance earlier than others. Guai Zhou Magu, Nangen 15, and Peng Chiu Moung were resistant from the 9th leaf and Taichung Sen 5 was resistant from the 11th to 12th leaf (Fig. 1). All flag leaves were BB resistant. Six cultivars were resistant to the four races at booting stage. Wan Mi Hsiang, 3330 and Chin Kong Tao 3 were resistant only to some races at maturity (see table).

Characterizing adult plant resistance to bacterial blight (BB)

Zhang Qi and T. W. Mew, IRRI 1. Adult plant resistance of selected Chinese cultivars

We evaluated 30 Chinese rice cultivars for BB resistance at IRRI. Nine cultivars appeared to have adult-plant resistance. This study seeks to understand how such adult-plant resistance is expressed. Effect of plant growth stages. The 9 cultivars were evaluated for BB resistance 21 and 45 d after sowing and at booting. Their response to the four Philippine races of Xanthomonas campestris pv. oryzae differed with growth stage. All cultivars were very susceptible as seedlings but with age developed resistance to one or all of the races (see table). Guai Zhou Magu scores for race 1 decreased from 8.5 as seedlings to 5.5 at maximum tillering and 1.0 at booting. Kwang-er-ai 5 disease scores decreased from 7.5 as seedlings to 5.7 at maximum tillering and

Adult plant BB resistance of Chinese varieties at seedling, maximum tillering, and adult stages. IRRI, 1984.

Resistancea to given race Variety

Guai Zhou Magu Nangen 11 Peng Chiu Moung Nangen 15 Kwang-er-ai 5 Taichung Sen 5 3330 3 Chin Kong Tao Wan Mi Hsiang Shi-zu IR1545-339 TN1 a By

PXO 6 1

PXO 86

PXO 79

PXO 71

SS

MTS

BS

SS

MTS

BS

SS

MTS

BS

SS

MTS

BS

8.5 6.5 6.5 6.7 8.5 7.0 7.5 7.0 9 1.0 1.8 9

5.5 4.0 3.1 5.5 6.2 4.7 5.7 4.3 5.4 1.3 3.0 8.0

1.0 1.0 1.2 2.0 2.7 3.0 3.5 3.5 4.7 1.0 1.0 6.8

8.5 6.3 6.1 6.5 6.5 7.5 6.7 6.7 7 3.0 3.5 9

3.1 3.0 1.3 3.0 5.0 4.7 3.3 3.7 3.0 1.0 3.0 6.7

1.1 1.0 1.0 1.7 1.5 2.0 1.6 1.7 1.3 1.0 1.0 4.3

8.0 6.5 6.0 6.5 9.0 9.0 7.2 6.7 8.5 2.5 3.2 9

5.2 3.3 3.0 5.6 7.0 5.4 5.4 4.8 5.0 1.3 2.0 7.3

1.0 1.0 1.0 2.8 2.7 3.0 2.7 1.2 5.0 1.0 1.0 6.3

7.0 6.0 6.2 7.0 9.0 8.0 7.2 7.3 9 1.0 6.8 9

5.0 3.5 3.2 5.1 7.0 4.3 5.5 6.6 6 1.2 5.0 7.3

1.4 1.0 1.0 1.0 2.8 3.0 4.0 6.8 5.0 1.0 6.0 7.0

the 1980 Standard Evaluation System for Rice scale. tillering stage, BS = booting stage.

SS = seedling stage, MTS = maximum

IRRN 9:6 (December 1984) 3

1. Reactions of 3 rices to the 4 BB races from 6th to flag leaf. IRRI, 1984.

2. Greenhouse testing of Xa 6 and Xa 3 genes for BB resistance

Rices with adult plant disease resistance are disease susceptible as seedlings and develop resistance as they mature. Zenith, Malagkit Sungsong, and lines IR1695 and IR944 derived respectively from them have the Xa 6 gene for BB resistance. Wase Aikoku 3 has the Xa 3

gene. We evaluated the rice for resistance expression in the IRRI greenhouse. Four BB races were inoculated 4-5 times at the 6th to flag leaf of the same plants. TN1, the susceptible check, was susceptible to the four races at all leaf positions (Fig. 2). IR1545-339, a line with differential BB resistance, was resistant to races 1, 2, and 3 and susceptible to race 4 at all leaf positions. Zenith was resistant from the 11th to the flag leaf, and IR1695 developed BB similarly. M. Sungsong was resistant from the 9th leaf and IR944, from the 12th leaf. When planting order was staggered to synchronize inoculation of different leaf positions, Zenith and M. Sungsong developed resistance to the 4 races at similar leaf positions (Fig. 3). Wase Aikoku 3 had adult plant resistance only to races 1, 2, 4, and was resistant to race 3 at all leaf positions (Fig. 2).

3. Reactions of Zenith and Malagkit Sungsong inoculated with 4 BB races at the same time. IRRI, 1984. 3. Influence of temperature on the Xa 6 gene for BB adult plant resistance

2. Reactions of Wase Aikoku 3 and TN1 inoculated with 4 BB races at the same time. IRRI, 1984.

4 IRRN 9:6 (December 1984)

High temperature favors BB development, but it is not known whether adult plant resistance controlled by the Xa 6 gene is stable in high temperature.

We evaluated BB resistance of Zenith, M. Sungsong, IR1695, and IR944 at 33-25, 29-21, and 25-20°C ranges in growth chambers with 70% relative humidity. The four cultivars have the Xa 6 gene. Zenith and M. Sungsong resistance was unaffected by temperature changes. However, resistance by leaf position was not consistent with greenhouse observations. Zenith and M. Sungsong expressed resistance best at booting stage (Fig. 4, 5). Lesions developed slowly, gradually yellowed, and stopped growing. The cultivars showed resistance earlier at 25-20°C than at 29-21°C. Temperature affected BB development more in IR1695 and IR944. At higher temperatures, lesions were longer than those of their parents, but the difference was insignificant at booting. Temperature did not affect TN1 lesion development.

4. Disease reactions of Zenith to BB races at 3 temperature ranges. IRRI, 1984.

5. Disease reactions of Malagkit Sungsong to the 4 BB races at 3 temperature ranges. IRRI, 1984.

4. Bacteriophage method for estimating X. campestris pv. oryzae multiplication

in infected rice leaves

Taking direct counts of X. campestris pv. oryzae cells by plating on ordinary media is impossible because the bacterium is slow growing and subject to contamination, especially in the tropics. We tested the bacteriophage method for estimating bacterial multiplication on rice leaf tissue. A suitable bacterial strain and a phage strain were selected and a one-step growth experiment was done to characterize the phage-bacterium relationship. A titration curve of the bacteria densities with the phage also was established for reference. The estimate was based on plaque-forming units (Pfu) caused by infection of the bacterial cells by the phage particles. We used a titration curve based on a serial dilution of isolate PXO 61 of BB pathogen in response to phage strain P-80 (Fig. 6). To estimate multiplication in Zenith leaves, six 5-cm-long led samples infected with PXO 61 were observed at different times after inoculation. The samples were disinfected with 70% ethanol and rinsed several times in sterile distilled water. The leaf specimens were homogenized in 5-ml filter-sterilized PSB medium. The leaf extract was diluted serially. For a viability count, 0.1 ml of the extract was

7. Relationship between phage count (PFu/cm2) and colony (CFu/cm2) at different leaf positions of Zenith with BB lesions. IRRI, 1984. 6. The titration curve of bacterial density with a standard phage concentration. IRRI, 1984.

plated on PSA medium. The rest was mixed with a standard phage concentration. Ten minutes after incubation at 28ºC in aeration, the mixture was centrifuged

to remove the excess phage. The precipitate was resuspended and incubated for 20 min to estimate phage absorption by the bacterial cells. Final phage plating was 10 h after incubation. The correlation between viability count for bacteria and phage count as an indication of bacterial multiplication is shown in

IRRN 9:6 (December 1984)

5

Figure 7. The bacteriophage method seems reliable and efficient for detecting bacterial multiplication in Pfu larger than 10 3/ml. 5. Relation of lesion development and bacterial multiplication in different leaf positions of Zenith inoculated with Xanthomonas campestris pv. oryzae

Zenith, with Xa 6 gene for BB resistance, shows resistance from the 11th leaf. It is unclear if bacterial multiplication in susceptible and resistant leaf positions varies. We investigated bacterial multiplication in the 6th, 9th, l0th, and 12th

leaf positions on Zenith using the bacteriophage method. Six samples from each leaf position were examined at 1, 24, 48, 72, and 158 h after inoculation (HAI). Lesion development was measured at the same time. On the susceptible 6th, 9th, and 10th leaf positions, lesions began to develop 48 HAI and grew very fast. On the 12th leaf, the lesions were visible 96 HAI, and developed slowly. Two weeks after inoculation, lesion length was 23.6, 18.2, 16.4, and 2.4 cm on leaves 6, 9, 10, and 12 respectively (Fig. 8). The phage count, expressed as plaqueforming units/cm 2 leaf area, on leaves 6, 9, and 10 increased 24 HAI, indirectly

indicating bacterial multiplication. Phage count at 48 HAI increased very fast. It peaked at 72 h, than slightly declined. Leaf tissue was totally infected at 120 and 158 h. The phage count on leaf 12 also increased 48 HAI, but was less than on other leaves and declined faster (Fig. 9).

9. Multiplication of X. campestris pv. oryzae on leaves 6, 9, 10, and 12 of Zenith estimated by the phage method. IRRI, 1984.

Individuals, organizations, and media are invited to quote or reprint articles or excerpts from articles in the IRRN. 8. BB lesion development on different leaf positions of Zenith in the greenhouse. IRRI, 1984.

Performance of HKR101 under bacterial blight (BB) stress

R. Pal, A. Singh, D. V. S. Panwar, and S. C. Ahuja, Haryana Agricultural University (HAU) Rice Research Station, Kaul 132021, Haryana, India

Whole plots were inoculated 30 d after transplanting by cutting 5 cm from leaf tops with a sickle dipped in inoculum. Inoculum was prepared by soaking 1-cm pieces of infected leaves for 20 min. Al-

Performance of HKRl0l under BB stress, Haryana, India. BB reactiona

Variety

HKR101 is a medium-duration semidwarf rice with long bold grains. It was developed at HAU Rice Research Station. We evaluated artificially inoculated HKR101 for BB resistance in a replicated trial from 1980 to 1983. Check varieties were Jaya and PRl06.


though HKR101 was as susceptible to BB as the check varieties, it yielded 16% more (see table). HKR101 has better grain quality than Jaya or PR106, and equal milling recovery.

HKR101 Jaya PR106 CD at 5% CV % a IRRI

9 9 9

Yield (t/ha) 1980 1981 5.0 4.4 4.3

6.0 4.9 5.1

.8 .9 11.12 10.7

Pani- Kernel Kernel Length- Milling Duration cles/ length breadth breadth recovery (d) 1982 1983 Mean m 2 (mm) (mm) ratio (%) 4.9 4.1 4.4

3.7 3.2 3.0

1.1 15.97

.4 7.03

Standard Evaluation System for Rice.

4.9 4.2 4.2

144 146 147

306 281 292

7.3 6.6 7.1

2.5 2.6 2.1

2.9 2.6 3.4

66 66 66

GENETIC EVALUATION AND UTILIZATION

Insect resistance Reaction of rice cultivars to pink stem borer (PSB)

D. K. Garg, Vivekananda Laboratory for Hill Agriculture, Indian Council of Agricultural Research, Almora, U.P. India 263601 In 1981 kharif we screened 84 rices for reaction to PSB Sesamia inferens in the field at Hawalbagh, Almora, where the pest is endemic. Thirty-day-old seedlings were transplanted, 2 plants/hill at 20- × 10-cm spacing in 2-row plots 2.5 m long. Test varieties selected were stem borer-resistant and tolerant entries from various national and international nurs-

Genetics of resistance to whitebacked planthopper (WBPH) in two rices

J. P. Singh, J. S. Nanda, and H. Singh, Plant Breeding Department, G. B. Pant University of Agriculture and Technology, Pantnagar, 263145 India WBPH Sogatella furcifera Horvath causes serious damage in Madhya Pradesh, Uttar Pradesh, and Punjab. The insect lives with brown planthopper (BPH) at the base of rice plants and causes hopperburn. We studied the genetics of resistance to WBPH in two resistant varieties: Balamawee and ARC10464. The two were crossed with susceptible TN1. Balamawee and ARC10464 also were crossed to learn the allelic relationship of the resistance

Promising gall midge (GM) resistant rices with short to medium duration

N. Kulkarni, rice breeder; P. P. Reddy, rice research assistant; and G. M. Rao, senior rice scientist, Agricultural Research Station (ARS), Warangal 506007, India In the northern Telangana region of Andhra Pradesh, uncertain monsoon

eries that were screened at Hawalbagh in 1980. VL 8 and China 1039 were the resistant and susceptible checks. Pest incidence was heavy from Sep-Oct to panicle bearing. Whiteheads caused by stem tunnelling were counted at peak incidence on 10 hills of each variety, 75-80 d after transplanting. Cultivars were scored as resistant (0-5% infestation), moderately resistant (5.1-10%), susceptible (10.1-25%), and highly susceptible (above 25%). Eight cultivars were resistant and 11 were moderately resistant. The rest were susceptible or highly susceptible (see table).

Varietal resistance to PSB, Hawalbagh, India.

genes. The F1 and F2 populations were evaluated for WBPH reaction by bulk screening (see table) Resistance in each of Balamawee and ARC10464 is governed by a single recessive gene. In both the crosses with TN1, the F 1 plants were susceptible and

the F2 plants segregated as 3 susceptible: 1 resistant. In the cross Balamawee/ ARC10464, the F 1 plants were susceptible and the F 2 segregated as 9 susceptible: 7 resistant, indicating that the recessive genes for resistance in both varieties are nonallelic.

Reaction

Cultivars

Resistant (0-5%)

HPU803, HPU2199, IR9129-192-24-3, IR9758-150-3, IR19774-34-2-1, KAU 2110, VRS163-2-3, VRS291-3-1, VL8 (resistant check)

Moderately resistant (5.1- 10%)

ARC11981, Fuzi 102, IR2053-521-1-1, IR7167-33-2-5, IR9129-263-3-3-2-3, IR9782-111-2-1,. IRAT102, K228-8-3, K427, VRS245-2-1, VRS598-3-1

Reactiona of F1 and F 2 populations to WBPH, Pantnagar, India. F2 reaction Cross

F1 reaction

TN1/Balamawee TN1/ARC10464 Balamawee/ARC10464 aS

S S S

Total (no.)

R (no.)

S (no.)

137 136 189

39 40 77

98 96 112

Assumed genetic ratio 1:3 1:3 7:9

X2

P value

0.88 1.41 0.56

0.50-0.30 0.30-0.20 0.50-0.30

= susceptible, R = resistant.

conditions delay rice planting and crops suffer severe GM infestation. GM damage is particularly serious in Sep and Oct when there are high rainfall and humidity and many cloudy days. We sought to develop 110- to 140-d varieties with GM resistance. Following are some popular GM-resistant varieties developed at ARS.

Surekha (IR8/Siam 29) is 80 cm tall with dark green foliage and erect leaves. It has 130- to 135-d duration and is suitable only for the monsoon season. It is lodging resistant, fertilizer responsive, and can be planted in late Jul. If planted late, 10- × 10-cm spacing is recommended. Each panicle has about 170 long, slender, translucent grains. Seed


7

dormancy is 10-15 d at harvest. It yields 5.5 to 6.0 t/ha. WGL 22245 (IR579/W12708) is 80 cm tall with compact panicles. Leaves have a purple margin. It is photoperiodinsensitive with 125-d duration in monsoon and 135 d in winter. Grains are translucent. It has stem borer (SB) and

bacterial blight resistance, and yields 6.0 to 7.5 t/ha. It is recommended for release as Pothana. WGL 26889 (IR22/12708) is a 145-d variety suitable for the monsoon season. It is SB-resistant with fine grains, and yields an average 6.0 t/ha. It is being tested in minikit trials.

Reaction of yellow stem borer (YSB)

Reaction of YSB resistant accessions to major rice pests and RTV, Coimbatore, India.

resistant accessions to other rice pests

N. Chandramohan and S. Chelliah, Tamil Nadu Agricultural University, Coimbatore 641003, India

In the screenhouse we tested six accessions with resistance and moderate resistance to YSB for resistance to brown planthopper (BPH), whitebacked planthopper (WBPH), green leafhopper (GLH), leaffolder (LF), white leafhopper (WLH), and rice tungro virus (RTV). W1263 was resistant to LF, BPH, WBPH, and GLH and moderately resistant to RTV (see table). Co 18 and

Accession W1263 Co 18 IR13641-4 IR13639-39 Sornavazhai Jaya (susceptible) TN1

WGL 20506 (Tella Hamsa/W12708) has 105-d duration and is especially suited for sowing in late monsoon, as late as mid-Aug. Grains are long and slender with a light brown husk. Yield averages 4.5 to 5.0 t/ha.

Mean resistance rating a YSB 1.0 4.0 4.0 4.0 6.5 9.0

a bc bc bc c –

GLH

d

4.0 6.0 7.0 5.6 7.0 6.5 9.0

a ab bc ab bc abc c

WLH 6.3 3.6 6.3 5.6 7.6 5.0 9.0

a

bc

bc b cd ab d

BPH 3.6 3.6 7.6 5.6 3.0 7.0 9.0

a a b

cd

a bc

d

WBPH

LF

4.3 a 3.6 a 5.0 ab 5.0 ab 4.3 a 6.3 ab 7.6 b

1.8 a 6.2 bc 6.6 c 5.4 b 9.0 d 9.0 d –

RTV

b

5.0 a 7.6 c 7.0 bc 5.0 a 7.0 bc 9.0 d –

a By

the 1980 Standard Evaluation System for Rice. In a column, means followed by the same letter are not statistically different. b Rating scale based on field evaluation.

IR13639-39 were moderately resistant to BPH, WBPH, and WLH. IR13641-4 was moderately resistant to WBPH and

moderately susceptible to other pests. Sornavazhai was resistant to BPH and WBPH.

GENETIC EVALUATION AND UTILIZATION

Adverse soils tolerance Tolerance for iron deficiency in rice

B. N. Singh, senior rice breeder; and B. P. Singh, junior scientist, Rajendra Agricultural University, Bihar, Pusa, Samastipur 848125, India Fe deficiency is a major constraint to increasing the area planted to high yielding varieties in the calcareous soils of north Bihar. Major calcareous areas are in Gopalganj, Saran, Siwan, Vaishali, Muzaffarpur, Samastipur, Begusarai, East Champaran, and parts of West Champaran and Darbhanga. Soils have pH 7.7 to 9.8, electrical conductivity 0.1 to 4.2 dS/m, 0.1 to 1.0% organic carbon, 4 to 49% available CaCO 3 , and low available P. Nurseries are dry-seeded and seedling leaves whiten in the nursery beds. Fe deficiency


symptoms are yellowing of young leaves and interveinal chlorosis which becomes whitish yellow, then ivory. Varieties differ in susceptibility to Fe deficiency. We screened lines for Fe deficiency in the field at Pusa beginning in 1981 wet season. The first trial was nonreplicated. In the next, tolerant lines were evaluated in three replications. Symptoms

were visible 15 to 20 d after seeding. IET7972 and IET7973 were tolerant of Fe deficiency. Br 34, Br 8, and TCA84 were moderately tolerant (Table 1). Most of the released varieties were susceptible to highly susceptible. Tolerant and moderately tolerant entries were photoperiod sensitive and are pureline selections from land races.

Table 1. Varietal reaction of certain elite lines to Fe deficiency, Samastipur, India. Tolerance score

Plant infection (%)

1 3 5

up to 1 1– 5 5 – 25

7

25 – 50

9

50 – 100

Line IET7972 (TCA148-3), IET7973 (TCA62-31-1) Br34, Br8, TCA84 UPR238-42-2-3, IET5882, UPR79-17, T141, NP49, IET6263 Rasi (IET1444, Pankaj, Janaki (IET9971), IET7970, KMP40, IET5883 Pusa 33, Pusa 2-21, Ratna, Rajendra Dhan 201, Sita, Jaya, Mahsuri, Saket 4, Radha (IET6261), UPR79-14, IR4568-86-1-2-3, RP1045-403-1, IR1157-52, UPR254-81-1-TCA, Br9, Katarni

Total Fe content in the leaves of tolerant and susceptible lines was unrelated to deficiency symptoms (Table 2). However, orthophenanthroline reactive Fe 2+ content of the leaves appeared to be related with deficiency symptoms. Lines with less than 30 ppm orthophenanthroline reactive Fe 2+ in the upper leaves were more susceptible than those with 30 to 40 ppm Fe 2+. Lines with more than 40 ppm Fe2+ were tolerant. Dry matter accumulation was significantly and positively correlated with orthophenanthroline reactive Fe 2+ ( r = 0.90**).

Table 2. Total dry matter content, Fe, and orthophenanthroline reactive Fe2+ in upper leaves of ric genotypes, Samastipur, India. Entry IET7973 IET7972 IET5882 Pankaj IET6263 Pusa 33 Mahsuri Saket 4 T141

Dry matter yield (g/20 plants)

Total Fe (ppm)

6.7 6.3 6.0 3.4 5.2 3.1 2.6 2.7 3.6

240 255 260 375 450 490 337 288 500

Orthophenanthroline Fe2+ (ppm) 50 42 37 33 36 32 28 30 33

Pest control and management DISEASES Effect of planting date on rice tungro virus (RTV) infection

B. N. Singh, senior rice breeder; and Y. Prasad, senior scientist, Rajendra Agricultural University, Bihar, Pusa 848125, India In 1980 wet season RTV infection increased in north and south Bihar. At the Pusa Experimental Farm, RTV developed the first week of Aug and attained maximum severity in Sep. In a yield evaluation trial with 16 entries planted at 3 dates, RTV infection developed at different times. The entries were planted in a randomized block on 25 May, 9 Jun, and 24 Jun 1980 and 30-d-old seedlings were transplanted in 20- × 15-cm spacing in 7.5-m2

A new rice virus disease in India

V. Mariappan, H. Hibino, and N. Shanmugam, Tamil Nadu Agricultural University, Coimbatore, India In late samba 1983, many rice varieties with yellow-orange leaves were observed in farmer fields and at the University of Coimbatore. Only a few plants showed symptoms that resembled those of rice

plots. NPK was applied at 80, 40, and 20 kg/ha. PK was applied basally and N was applied in three splits. The maximum score from three replications was used to classify entries for RTV reaction (see table). Green leafhopper population was high. Only RP967-11-1-4-2-2 was infected on the first planting date, but many other entries developed RTV when planted on the second and third dates. Pusa 33, Pusa 2-21, Saket 4, and Ratna were resistant. Rajendra Dhan 201 and IET5656 had intermediate resistance. The recorded infection rate show that agronomic manipulations such as early planting can minimize RTV infection in susceptible cultivars. Plant age and varying incubation period also may affect disease development.

tungro virus (RTV). Plants had mild stunting and increased tillering. Brown planthopper (BPH) was in the fields. Infected plants were collected and transmission tests were conducted by using the green leafhopper (GLH) Nephotettix virescens Dist. and BPH Nilaparvata lugens Stål. Virus-free GLH adults given 4-d acquisition access feeding on source plants were transferred to 10-d-old TN1

RTV infection of varieties planted at different dates at Pusa, India. RTV reaction a

Entry

25 May 9 Jun 24 Jun

Pusa 33 Pusa 2-21 Govind (UPR82-1-7) Saket 4 (CR44-35) Ratna Prasad Jaya IR8 Sita Rajendra Dhan 201 BG90-2 SPR7284-57-5 RP967-11-1-4-2-2 Pankaj RP975-109-2 (IET5656) MR1

1 1 1 1 1 1 1 1 1 1 1 1 7 1 1 1

1 1 1 1 1 7 7 7 7 1 9 1 7 1 1 7

1 1 7 1 1 9 9 9 9 5 9 9 9 7 5 9

aBy

the 0–9 scale of the 1980 Standard Evaluation System for Rice.

seedlings at 2 insects/seedling for 4-d inoculation access. The inoculated plants did not develop disease symptoms (Table 1). Second-instar nymphs from a virusfree BPH colony were released on source plants for 7-d acquisition access feeding, and then collected and released on 10-dold TN1 seedlings at 2 insects/plant for 10-d inoculation access feeding. The inoculated plants developed yellow-


9

orange leaves 25 d later. The plants were slightly stunted and had more tillers than the control plants. BPH-inoculated Oryza nivara developed similar symptoms but those exposed to GLH did not. Dried leaves of infected TN1 plants were sent to IRRI for serological tests. In a latex test using antiserum to rice grassy stunt virus (GSV), sap of the dried leaves reacted positively up to 1:8 dilution; sap of GSV-infected fresh leaves collected at IRRI reacted positively at 1:512 dilution; and sap of virus-free fresh leaves did not react, even at 1:1 dilution (Table 2). We therefore identified the new disease as a strain of GSV. It is similar to GSV strain 2 in the Philippines. So far there are no reports from India of BPHtransmitted leaf yellowing.

Rice yield loss to sheath blight (ShB)

P. Arunyanart, A. Surin, W. Rojanahasadin, R. Dhitikiattipong, and S. Disthaporn, Rice Pathology Branch, Division of Plant Pathology and Microbiology, Agriculture Department, Bangkhen, Bangkok, 10900, Thailand ShB, caused by Thanatephorus cucumeris (Frank) Donk, normally infects rice at tillering stage. ShB damage is increasing in Thailand. In Jul-Dec 1983, we studied yield loss caused by different stages of ShB infestation to determine an economic threshold at which to apply chemical controls. The experiment was in a randomized complete block design with 4 replications of 5 treatments of different disease intensities: 0, 3, 5, 7, and 9 by the Standard Evaluation System for Rice. RD7, the most ShB-susceptible variety, was transplanted in 6- × 4-m plots and artificially

Table 1. Transmission of the new virus to TNl and O. nivara by N. virescens and N. lugens. Coimbatore, India, and IRRI. TN1

Insect

O. nivara

Inoculated

Infected

Inoculated

Infected

25 61

0 19

6 18

0 9

N. virescens N. lugens

Table 2. Serological reaction of the sap of leaves infected with new virus or GSV to GSV antiserum by latex test, IRRI. Reaction to given sap dilution

Sample

Undiluted

Dried TN1 leaf infected with new virus Fresh TN1 leaf infected with GSV Fresh TN1 leaf free from virus

2

4

8

16

32

64

128

256

512

+

+

+

+

–

–

–

–

–

–

+ –

+ –

+ –

+ –

+ –

+ –

+ –

+ –

+ –

+ –

+ = positive, – = negative.

inoculated at tillering by inserting a packet of mycelia and sclerotia of T. cucumeris in each hill. Validamycin was used to keep disease intensity at the

Yield loss to bacterial blight (BB) in central Thailand

W. Sirisantana, N. Nilpanit, S. Phawichit, P. Kiatsuranont, and S. Disthaporn, Rice Pathology Branch, Plant Pathology and Microbiology Division, Agriculture Department, Bangkhen, Bangkok, Thailand Relationship between lesion length and percentages of yield loss, straw weight loss, and empty grains. Bangkhen, Thailand.

Rice yield characters affected by different ShB severity, Bangkhen, Thailand. Disease index 0 3 5 7 9

10

Av yield (kg/8 m) 4.05 a 3.42 b 3.10 bc 2.88 c 2.39 d

Yield reduction (%)

Av straw wt (kg/8 m)

0a 15 b 22 bc 28 c 40 d

26 a 24 ab 21 b 18 c 15 c


desired levels. Straw weight, grain weight, and number of empty grains were analyzed. Infected plants with disease severity 3, 5, 7, and 9 reduced yield 15, 22, 28, and 40% (see table). Correlation between disease severity and percent yield loss, straw weight loss, and empty grains was a linear regression (see figure).

100-grain wt (g) 3.0 3.0 2.9 2.9 2.6

a a a ab b

Empty grain (%) 21 a 24 b 26 b 30 c 33 d

BB, caused by Xanthomonas campestris pv. oryzae, is a serious constraint in parts of Thailand. We studied yield loss caused by BB at Bangkhen Rice Experiment Station in 1983 rainy season. RD1, a susceptible rice cultivar, was transplanted in 4 of 5 10-m 2 plots. Ammophos 16-20-0 was topdressed at 250 kg/ha, and plants were fully protected from other diseases and insect pests. Every hill in alternate rows was clip-inoculated at midtillering. When

Yield from rice with different intensities of BB at booting and milk stages, Bangkhen, Thailand.

Disease intensity a (%) 0 0-5 5-10 10-15 15-20 20-25 25-30

Grain wt (g) Booting stage

Milk stage

33.9 33.5 32.8 30.5 25.2 31.9 –b

49.5 47.9 51.8 48.9 42.5 50.0 51.3

Empty grain (%) Booting Milk stage stage 8 17 10 9 16 15 –b

8 9 9 8 10 12 12

a

% disease severity in hill = sum of % BB severity on flag leaves and 2d leaves number of tillers in hill × 2 b – = no information.

Estimated linear relationship between % empty grains and % BB intensity on rice variety RD1. Bangkhen, Thailand.

infection was uniform throughout the plots, 135 hills were randomly tagged in noninoculated rows. Disease intensity was recorded at booting and milk stage. At booting stage, there was no correlation between grain weight, percentage of empty grains, and

disease severity. At milk stage, percentage of empty grains was significantly related to different disease intensities (see table). The correlation of empty grains and disease intensity was calculated as a simple linear regression equation y = 8.2369 + 0.1306X** (see figure), which

implied that increasing disease intensity increased percentage of empty grains. Because yield component analysis was based on data from individual hills and because of the human influence, a high C. V. was noted. Therefore, grain weight did not correlate with disease intensity.

Bacteriophage strain of Xanthomonas

Forty X. campestris isolates were isolated from infected leaves using Wakimoto’s potato semisynthetic agar (PSA) medium. Twenty-two bacteriophages were isolated from irrigation water by mixing 1 ml of the water sample with 2 ml of indicator bacterial suspension, then adding to 5 ml of the melted PSA medium. The mixture

was poured into sterilized petri dishes. To maintain the phage, we transferred single plaques that developed 15-20 h later to test tubes containing a vitaminfree casein hydrolysate solution. Different lysotypes were determined by testing all bacteriophage samples against all bacterial isolates.

campestris pv. oryzae from parts of Thailand

N. Nilpanit, W. Sirisantana, P. Kiatsuranont, S. Phawichit, and S. Disthaporn, Rice Pathology Branch, Plant Pathology and Microbiology Division, Agriculture Department, Bangkhen, Bangkok, Thailand The bacteriophage technique can be used to forecast a bacterial blight (BB) outbreak. Phage population, determined by plaque counting, shows the population density of the host bacterium X. campestris in irrigation water. Plaques or clear zones induced by the phage appear only on certain bacterial isolates. Therefore, it is necessary to select bacterial isolates that are susceptible to phage strains in areas where the bacteriophage technique will be used to predict BB outbreak. We surveyed 19 provinces in central and northeastern Thailand for phage and host bacteria distribution (Table 1).

Table 1. Distribution of phage strains and X. campestris strains in some regions of Thailand. Province

Region

Lampang Pichit Petchaboon Singhaburi Aungthong Chainat Suphanburi Bangkok Pathumthani Kanchanaburi Khon Khaen Mahasarakarm Kalasin Sakonnakorn Udonthani Nongkai Nakornsajsima Buriram Phatalung

Northern Northern Northern Central Central Central Central Central Central Central Northeastern Northeastern Northeastern Northeastern Northeastern Northeastern Northeastern Northeastern Southern

a

X. campestris strain B B E B H A, B A, B A A, B A, D, D, D A, F E

B, E B, C, D, E C, F, G E E E C,

Phage straina – – – – – TBP 1, TBP4, TBP5 TBP 2 TBP1, TBP3, TBP4 TBP 1, TBP4 – TBP 3 TBP 3 TBP 3, TBP5 – TBP 5 TBP 5 TBP 3 TBP 3 –

A dash means not found.


Twenty-two X. campestris bacteriophages were classified as having five phage strains: TBP 1, TBP2, TBP3, TBP4, and TBP5 (Table 2). Forty isolates were classified by their susceptibility to those phage strains into eight bacterial strains, A-H. Phage strains TBP l and TBP2 were the most widely distributed, and bacterial strain A was most susceptible to all phage strains. Strain H was not susceptible. Bacterial strain A could be widely attacked where samples were taken. Bacterial strains A and D can be used as indicators for all phage strains dominant in those areas (Table 1).

Nitrogen fertilization and sheath rot (SR) development in rice

S. I. Akanda, A. K. M. Shahjahan, and S. A. Miah, Bangladesh Rice Research Institute, Joydebpur, Dhaka, Bangladesh

Table 2. Classification of X. carmpestris pv. oryzae based on bacteriophage sensitivity in Thailand. Phage strain

Bacterial strain

TBPl

TBP2

TBP3

TBP4

TBP5

A

+

+

+

+

–

B

+

+

–

+

–

C D E

+ + –

– – +

+ – –

– – +

– + –

F G H

– – –

– + –

+ – –

– – –

– – –

sail, a local improved variety. Recommended cultural practices were followed, including 65 kg P and 45 kg K/ha at final land preparation. Urea N was applied in equal splits at tillering and panicle initiation. The experiment was in a ran-

Bacterial isolates obtained TB 8206, 8208, 8212, 8214, TB 7536, 8004, 8211, 8221, TB 8210, 8227, TB 8203, 8222, TB 8201, 8207, 8224, 8235, TB 8215, 8231, TB 8229 TB 8003

8209, 8216, 8104, 8236 8228, 8223, 8213, 8301 8232

8234, 8202 8218, 8230 8204, 8205 8233 8225, 8226 8217, 8219

domized complete block design with 4× 3-m plots and raised levees. At early booting, all tillers of 10 randomly selected hills/plot were inoculated with S. oryzae cultured on sterilized rice grains. The grain inocula were pushed

SR, caused by Sarocladium oryzae, was identified in Bangladesh in the early 1970s. It has become a constraint to Nresponsive modem varieties (MV). We studied the effect of 0, 30, 60, 90, and 120 kg N/ha on SR severity in transplanted aman BR11, an MV, and Nizer-

1. ShR disease index 0-9 scale. Left to right: 0 = healthy and 9 = severe ShR development. Dhaka, Bangladesh.


2. Relationship between N fertilization and ShR severity in B11 and Nizersail during t. aman. Dhaka, Bangladesh.

partly into the middle portion of the flag leaf sheath and held there with scotch tape. At maturity, disease intensity (DI) was rated using a 0-9 scale. Zero indicated

Reaction to rice tungro virus (RTV) complex as influenced by insect pressure

R. C. Cabunagan, E. R. Tiongco, and H. Hibino, IRRI We inoculated five IR varieties with 1, 5, 10, 20, and 30 N. virescens per plant to test their reaction to RTV complex. The

no infection and 9 indicated complete flag leaf sheath discoloration and unemerged panicles (Fig. 1). Increasing N application significantly

increased DI in both varieties (Fig. 2). The regression coefficient (b) in both varieties was equal, indicating a similar trend.

insects were allowed 4-d acquisition access time on plants infected with both rice tungro bacilliform virus (RTBV) and rice tungro spherical virus (RTSV). Test plants were planted singly in clay pots and enclosed in mylar cages. One month after planting, insects were allowed 24 h inoculation access time on the plants. The second youngest leaf from each plant was

sampled for RTBV and RTSV by latex test 1 mo after inoculation. Infection with RTBV and RTSV increased in IR36 and IR42 when viruliferous insects/plant increased from 1 to 30. Only RTBV infection increased in IR50 and IR54, whereas an almost equal infection of both RTBV and RTSV, and RTBV alone was obtained in IR56 (see figure). Varieties infected only by RTBV (IR50 and IR54) may not serve as virus source because the virus could not be recovered by the vector insect. However, these test varieties may not be immune to RTSV infection (see table). Percentage infection of IR varieties when inoculated with RTSV at 1 insect/seedling, IRRI. Variety IR36 IR42 IR50 IR54 IR56 TN 1

Inoculated seedlings (no.) 36 38 38 38 39 102

Infected seedlings No.

%

21 15 6 8 32 85

58.3 39.4 15.7 21.0 82.0 83.3

Reaction of IR varieties to RTV complex when inoculated with varying numbers of viruliferous insects per plant, IRRI.

Evaluation of National Screening Nursery (NSN) and international Rice Observational Nursery (IRON) trials for bacterial blight (BB) and stem rot (SR) resistance

S. C. Ahuja, A. Singh, R. Pal, and U. Ahuja, Rice Research Station, Kaul 132021, India We evaluated NSN and IRON varieties for BB, kresek, and SR resistance in kharif 1980, 1981, and 1982.

Each variety was planted in two 5-mlong rows. Plants were inoculated with kresek at 20 d after transplanting (DT) and with BB at 45 DT. Inoculation was by cutting 5 cm of the upper leaves with a sickle dipped in inoculum prepared by soaking small pieces of naturally infected leaves in water for 20 min. Infection was scored on a 1-9 scale. SR screening was done under natural incidence, and evaluated at maturity on a

1-5 scale. BB intensity was high in most trials. SR incidence was high only in 1982. Resistant entries were selected and retested. Entries with consistent reaction to SR and BB for 2 yr or longer are given in the table. Sixteen NSN and 14 IRON entries were consistently resistant. Resistant IRON entries BR171-2B-8, IR13420-63-3-1, IR19660-131-3-3-3-3, IR9763-11-


Summary of results of NSN and IRON evaluation against BB, kresek , and SR, Haryana, India. Year

Trial

Test

Severity index

1980

NSN-I NSN-II

BB

6.6

High

1981

NSN-I IRON

Kresek BB

6.9 7.4

1982

NSN-I

BB Kresek

IRON

SR BB

Entries (no.) showing rating 1

2

3

4 a

5

7

9

Total entries (no.)

18

154

92

33

268

69 6

– – – – – –

72 21 68 206

71 –

158 38

157 137 54 11 _

321 254 334 327

79 35

49 67 106 104 – 93

– – – –

26 12 12 26

5.4 5.8

High High Moderate Moderate

1 – 32 1 39 –

– –

4.0 7.0

High High

4 3

23 –

28

180

133

IET8353, and IET4141) to SR, kresek, and BB.

276

330 343

aEntries

resistant for more than 2 yr — NSN (resistant to BB and K): IET nos. 7061, 7100, 7338, 7349, 7393, 7419, 7420, 7421, 7431, 7434, 7447, 7662, 7707, 7736, 7752, 7753. IRON (resistant to BB): BR161-2B-53, BR161-2B-58, BRl71-2B-8, IR134-20-6-3-3-1, IR19660-131-3-3-3, IR976311-2-2-3, IR17488-2-3-2, IRl9661-23-3-2-2, IR17494-32-1-1-3-2, IR75-2878, IR50, IR54, DR55-9, MRC 603-383. NSN entries resistant to SR and BB for 2 yr: IET nos. 7753, 8169, 8175, 8195, 8197, 8259, 8303, 8319, 8322, 8325, 8327. NSN entries resistant to SR, kresek, and BB (1982): IET nos. 8140, 8145, 8353, 4141.

Pest control and management Inheritance of virulence of the North Sumatra population of the brown planthopper (BPH) on IR42

K. Sogawa and Djatnika Kilin, IndonesiaJapan Joint Programme on Food Crop Protection, Directorate of Food Crop Protection, P. O. Box 36 Pasarminggu, Jakarta, Indonesia We studied the genetic nature of virulence of the North Sumatra (NS) BPH population. Nymphal development and adult longevity and maturity of the NS population, the Bogor population on Pelita I/1 that does not infest resistant rices, and their hybrid progenies were compared on IR42 seedlings. The F1 and F2 hybrid progenies were obtained by heterogametic pairing of the NS and Bogor BPH populations. The backcrossed progenies were bred by crossing the F1 with the NS or the Bogor population. Twenty 1st-instar nymphs and newly emerged brachypterous adult females were collected at random from each parental or hybrid population maintained on susceptible Pelita I/1, and placed in test tubes with 1- to 2-wk-old IR42 seedlings, 2 seedlings/tube. Nymphal development, and longevity and development of ovaries were recorded


2-2-3, IR17488-2-3-2, IR19661-23-3-2-2, IR17494-32-1-1-3-2, and MRC603-383 were included in advanced breeding trials. In the NSN, 11 entries were resistant to SR and BB and 4 (IET8140,IET8145,

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INSECTS

Table 1. Nymphal development of the NS and Bogor populations and their hybrid progenies on IR42 seedlings, Jakarta, Indonesia. Crossa

Nymphs tested (no.)

Female × Male NS × NS B×B NS × B B × NS (NS × B) 2 (B × NS) 2 NS (NS × B) B (B × NS)

20 20 20 20 20 19 20 20

Adult emergence (%) 80 20 30 10 30 21 55 35

Developmental period of nymphs which became adults (d ± SD)

Growth indexb

12.9 ± 1.3 15.5 ± 0.6 14.3 ± 1.5 14.5 ± 2.1 13.3 ± 0.5 12.8 ± 1.0 13.4 ± 2.4 14.4 ± 2.6

6.2 1.3 2.1 0.7 2.3 1.6 4.1 2.4

aNS

= North Sumatra population on IR42, B = Bogor population on Pelita I/1. b % adult emergence divided by mean duration of nymphal period in d.

Table 2. Longevity and maturity of adult females of the NS and Bogor populations and their hybrid progenies on IR42 seedlings, Jakarta, Indonesia. Crossa Female × Male NS × NS B×B NS × B B × NS (NS × B)2 (B × NS) 2 NS (NS × B) B (B × NS) a See

Females Gravid tested females (no.) (%) 20 21 20 17 20 20 20 20

footnote, Table 1.

90 5 5 18 30 10 50 25

Longevity (d ± S. D.) 16.0 ± 6.7 3.6 ± 2.7 3.9 ± 4.0 5.5 ± 6.1 6.5 ± 5.8 4.3 ± 4.5 12.5 ± 9.5 6.3 ± 5.8

daily. Experiments were conducted at room temperature (25-30°C). Parentage distinctly influenced nymphal development. Eight percent of the NS nymphs emerged as adults in 13 d. Only 20% of the Bogor population reached adulthood in 16 d. Development of the hybrid F1 and F2 nymphs from reciprocal crosses was similar to that of the Bogor population. When the F 1 with NS as maternal parent was backcrossed with the same population, nymphal development was intermediate between the NS and Bogor populations. However,

backcrossing to the Bogor population did not improve nymphal development on the resistant variety (Table 1). Newly emerged females of any parental or hybrid population placed on IR42 seedlings clearly fell into two discontinuous classes: one that became gravid and survived significantly longer

Possible genetic isolation between the Leersia and rice brown planthopper (BPH)

K. Sogawa and Djatnika Kilin, IndonesiaJapan Joint Programme on Food Crop Protection, Directorate of Food Crop Protection, P.O. Box 36, Pasarminggu, Jakarta, Indonesia It was reported that the Leersia -feeding BPH found on Leersia hexandra in North Sumatra is morphologically indistinguishable from the rice BPH Nilaparvata lugens, but distinctive from each other by their incompatible host requirements. To determine possible genetic barriers, we examined courtship reaction and crossability of the populations. Courtship reactions were observed by a seedling bridge method. A premating male and a female, 4 to 5 d old, were separately placed at the base of 2 rice seedlings about 10 cm apart in a 17 × 25 cm jar. The leaf blades touched to enable the BPH to communicate by seedling transmitted courtship signals.

(17.2 d), and another that quickly died (survived 3.5 d). Of the NS population, 90% of the females became gravid and survived about 18 d on IR42 seedlings. Most Bogor females died within 5 d. In the hybrid F 1 and F 2 progenies, 5-30% females became gravid with 4-7 d average longevity. Back-

crossing the F 1 hybrid and the NS population increased the parentage of gravid females, but backcrossing with the Bogor population had no such effect (Table 2). The results indicated that the NS population’s ability to infest IR42 is inherited from recessive genes when interbred with avirulent BPH populations.

When a male and female from the same population were tested, the male moved to the female on the other seedling and they successfully mated. Homogametic matings usually occurred within 4-5 min. Heterogametic matings between the Leersia- and rice-BPH seldom occurred except when the male and female met by chance through random wandering. To confirm our results, mating choice experiments were conducted using a similar method, but three seedlings were set at triangular positions with crossed leaf blades. In one test, a single rice-BPH female was placed on one of the three seedlings and one male each of Leersiaand rice-BPH were placed separately on each of the two other seedlings. Only the male rice-BPH reacted and mated with the female within an average 5 min. The male Leersia -BPH did not react. In another test, a single male Leersia -BPH was allowed to select between Leersiaand rice-BPH females. The male always moved to and mated with the female

Leersia-BPH within 4 min. Communication by acoustic courtship signals is not successful between the Leersia- and rice-BPH. Despite failure in courtship communication, Leersia- and rice-BPH can mate and produce viable hybrid progeny if confined on the same plant. However, the hybrid progenies were poorly adapted to both host plants. Percentage of adult emergence of the F1 BPH hybrids were 8-26 on both hosts (see table). The F 2 population also was viable, and survived better than the F 1 on the same host. We conclude that Leersia- and rice-BPH are noninterbreeding sympatric populations. Genetic interchanges between them are greatly restricted by unsuccessful courtship communication, incompatible host plant preference, and breakdown of host affinity in hybrid progenies.

Adult emergence of the Leersia- and rice-BPH, and their F 1 and F 2 hybrids on rice and L. hexandra, Jakarta, Indonesia. a Cross b ( × ) L×L R×R L × R R× L (L × R)2 d (R × L) 2 d

No. of adults emerged

% adult

Host

MF

BF

MM

BM

Rice Leersia Rice Leersia Rice Leersia Rice Leersia Rice Leersia Rice Leersia

0 0 0 0 0 3 2 1 1 10 7 9

0 21 29 0 7 2 3 0 6 4 16 0

0 1 6 0 1 0 3 3 3 4 9 9

0 24 12 0 3 8 2 0 1 1 13 0

c

emergence 0 92 94 0 22 26 20 8 22 38 90 36

a Fifty first instar nymphs were used for each test. Number of adults emerged was recorded 22 days after introduction of the nymphs. b L = Leersia- BPH, R = rice - BPH. c MF = macropterous female, BF = brachypterous female, MM = macropterous male, BM = brachypterous male. d Adults emerged on L. hexandra and Pelita I/1 were used, respectively.

Monitoring brown planthopper (BPH) biotypes by rice garden in North Sumatra

K. Sogawa and Ayi Kusumayadi, Indonesia-Japan Joint Programme on Food Crop Protection, Directorate of Food Crop Protection, Jl. Ragunan, P.O. Box 36 Pasarminggu, Jakarta; and J. S. Sitio, Balai Proteksi Tanaman Pangan, J1. Kary Jasa 4, Gedung Johor, Medan, Indonesia Monitoring BPH biotype nature or virulence is important in variety-oriented BPH management. To monitor BPH biotypes and forecast population surges, we designed a rice garden in which several rice varieties are planted separately in 5- × 5-m plots in a randomized block design. In Deli Serdang, North Sumatra, in 1983 dry season, we used that technique


to identify local BPH biotypes. Pelita I/1, IR26, IR36, IR42, IR46, IR56, and Bahbolon were transplanted in each plot with three replications on 6 Aug. BPH infested the plots soon after transplanting. There were bimodal population peaks at 4-5 and 7-8 wk, which corresponded to the maximum nymphal stages of the first and second generations. Between population peaks, brachypterous females emerged. Their population peaked at 6 wk. The BPH population declined sharply after 10 wk, probably because of drought. No hopperburn developed. However, statistically significant differences in BPH densities were recorded among the rice varieties at six insect development stages. Population was significantly higher on IR42 and the susceptible check Pelita I/1 (see table). Populations were particularly low on IR46, IR56, and Bahbolon. Interestingly,

Comparison of population density of the BPH on 6 different rice varieties at 6 different stages in the rice garden in Deli Serdang, North Sumatra, 1983. a

IR26, which had been attacked by BPH biotype 2, showed good resistance. Results indicated that the local BPH population was biotype 3, adapted to IR42, which corresponded with laboratory identification of locally

collected BPH. The rice garden method is recommended as a simple but highly practical method of monitoring BPH biotype shifts, and forecasting BPH population surge and development of other insect pests and diseases.

Relationship between biochemical characteristics of rice and establishment of yellow stem borer (YSB) larvae

Each accession was in 3 replications of 10 hills/replication. Ten days after larvae were released, single accessions were pulled and the leaf sheath and lumen were carefully observed to determine the presence and position of the larvae. Percent larval establishment was calculated based on larval recovery. The leaf sheaths and stems of accessions were analyzed for total N, crude silica, lignin, and cellulose. Larval establishment was lowest in W1263, followed by Co 18 and IR136414 (see table). It was highest in susceptible Jaya. Only crude silica content was significantly related to percent larval establishment. The resistant accessions had more silica than other accessions in their stems.

Inhibitory effects of insecticides on

N. Chandramohan and S. Chelliah, Tamil Nadu Agricultural University, Coimbatore 641003, India We conducted screenhouse experiments to determine the ability of YSB larvae to establish themselves on rice accessions with selected biochemical characteristics. Twenty-day-old seedlings of 6 accessions (see table) and the susceptible check Jaya were transplanted 1 /hill in 10cm earthen pots in a 90- × 60- × 5-cm galvanized iron tray filled with water. Fifty days after seeding, one freshly hatched larva was released on each tiller.

Insects/hill Variety

Pelita I/1 IR42 IR36 IR26 IR56 IR46 Bahbolon

Resistance gene None bph 2 bph 2 Bph 1 Bph 3 Bph 1 Bph 3

M-female (2 wk) 2.4 3.3 1.5 1.1 1.3 1.0 0.4

ab a bc bc bc bc c

F1 S-nymph (4 wk)

F1 L-nymph (5 wk)

B-female (6 wk)

252 a 202 a 81 b 16 bc 20 bc 3 c 1 c

67 a 70 a 20 b 7 b 5 b 4 b 1 b

4.3 4.3 0.9 0.4 0.2 0.1 0.02

W1263 Co 18 IR13641-4 IR13639-39 Sornavazhai Jaya

a a b bc c c c

6.0 a 7.3 a 1.7 b 0.1 b 0.2 b 0.2 b 0.1 b

followed by the same letter are not significantly different at 5% level. F1 = first generation, F2 = second generation, M-female = macropterous adult female, B-female = brachypterous adult female, S-nymph = 1st- to 3d-instar nymphs, L-nymph = 4th- to 5th-instar nymphs. Time in parentheses indicates weeks after transplanting.

Stem

Leaf sheath

Larval establishment (%)

Total N (%)

Crude silica (%)

Crude silica (%)

Lignin (mg/g)

Cellulose (mg/g)

9 20 23 45 45 50

3.6 2.4 5.0 4.9 3.1 3.1

4.8 2.3 0.6 1.4 3.7 1.7

11.40 9.87 12.12 5.85 3.17 6.51

417 532 279 143 583 464

671 608 737 887 566 710


60 83 27 7 0.2 0.3 0.1

F2 L-nymph (8-9 wk)

a Values

Larval establishment and biochemical characteristics of selected rice accessions, Coimbatore, India.

Accession

a a ab b b b b

F2 S-nymph (7-8 wk)

entomogenous fungi Metarrhizium anisopliae and Beauveria bassiana

R. M. Aguda, senior research assistant, IRRI; R. C. Saxena, principal research scientist, International Centre of Insect Physiology and Ecology, Nairobi, Kenya, and associate entomologist, IRRI; J. A. Litsinger, entomologist, IRRI; and D. W. Roberts, insect pathologist, Insect Pathology Resource Center, Boyce Thompson Institute of Plant Research, Ithaca, New York M. anisopliae and B. bassiana are the most commonly isolated entomogenous fungi from field-collected brown planthopper (BPH) in the Philippines. Because BPH resurgence is linked with insecticide application, it may be that insecticides applied to control BPH also inhibit natural enemies of BPH. We evaluated the effect of insecticides recommended for BPH control and BPH resurgence-causing insecticides on the germination of M. anisopliae and B. bassiana spores. Insecticide was mixed into the culture media before planting, or was surfaceapplied on hardened media. All insecticides significantly reduced spore germination of both fungi (see table). M. anisopliae was more sensitive to insecti-

Effect of insecticides on M. anisopliae and B. bassiana spore germination, IRRI, 1983. Spore germinationa (%) Insecticide

Insecticide mixed with media b M. anisopliae

B. bassiana

0

Insecticide mean

9

51

36

Insecticide mean

B. bassiana 95 b d 36 68 c 68 c 100 a

51

67

Causing BPH resurgencee 71 c 16 d 90 b 81 b 6 e 15 d 38 d 75 c 100 a 99 a

20 d 56 c 0 e 66 b 99 a

Azinphos ethyl Deltamethrin Methyl parathion MIPC No insecticide

M. anisoplia

Recommended for BPH control d 32 b 72 b 2 c 36 d 0 d 66 c 0 d 28 e 100 a 99 a

0 c l b 0 c 0 c 99 a

Monocrotophos BPMC Carbosulfan Azinphos ethyl + BPMC No insecticide

Insecticide on media surface c

77 c 89 b d 72 e 67 100 a

47

77

aIn

a column, means followed by the same letter are not significantly different at 5% level by DMRT. 300 random spores counted 24 h after insecticide application. bInsecticide mixed with the culture media at 40-45°C, then plated. Fungal spore suspension (0.3 ml/petri dish) was spread on the cooled and hardened media. cInsecticides and fungi spores were mixed together in suspension and 0.3 ml/ petri dish was spread on top of the hardened culture media. dAt the national recommended rate of 0.75 kg ai/ha. eAt the minimal rate that causes resurgence (0.50 kg ai/ha, except deltamethrin at

cides. Recommended insecticides reduced spore germination more than resurgencecausing insecticides did, probably because a higher dosage of the recommended insecticide was applied. Because both types of insecticides greatly inhibited spore germination of both fungi, it is unlikely that insecticides cause resurgence by counteracting the beneficial effect of entomogenous fungi. Among the BPH resurgence-causing insecticides, deltamethrin, the most powerful, had the weakest effect on spore germination. Only methyl parathion, the second most powerful BPH resurgencecausing insecticide, greatly reduced spore germination. Individuals, organizations, and media are invited to quote or reprint articles or excerpts from articles in the IRRN.

0.025 kg ai/ha).

Influence of flooding, fertilizer, and plant spacing on insect pest incidence

P. Karuppuchamy and S. Uthamasamy, Tamil Nadu Rice Research Institute, Aduthurai 612101, India We studied the influence of cultural methods on reducing insect pest incidence in rice in 1981 kuruvai. Continuous flooding and alternate flooding and draining; 15- × 10-cm, 20-

× 10-cm, and 30- × 10-cm spacing (water regimes and spacings were main plots); 50, 100, and 150 kg N/ha; and 42 and 83 kg K/ha (N and K treatments were subplots) were tested in a split-plot design with 3 replications. TKM9 was planted in 1 6-m 2 plots. Tillers and silvershoots were counted in 19 randomly chosen hills/plot 30 and 50 d after transplanting (DT). Populations of green leafhopper (GLH) and brown planthopper (BPH), and whorl maggot (WM) damaged leaves on 10 hills/

Insect population and grain yield as determined by cultural practice, Aduthurai, India. a Treatment Water management Continuous flooding Alternate flooding and draining

GLH/10 hills 19 b 13 a

BPH/10 hills 9 b 4a

WM (% damaged leaves)

GM (% silvershoots)

Yield (t/ha)

7 b 4a

2a 3 b

5.6 a 4.9 b

Spacing 15 × 10 cm 20 × 10 cm 30 × 10 cm

13 a 18 b 18 b

6 6 6

5 6 5

3 2 3

5.0 5.2 5.5

N level 50 kg/ha 100 kg/ha 150 kg/ha

15 a 16 a 18 b

3a 7 b 8 c

5 5 5

2 2 3

4.8 b 5.2 b 5.7 a

K level 42 kg/ha 83 kg/ha

17 16

6 6

5 5

2 3

5.2 5.3

aMeans

followed by the same letter are not significantly different at 5% level.

plot were counted 20, 45, and 70 DT. Grain yield was recorded. Alternate flooding and draining significantly reduced GLH and BPH populations and WM damage. The 10- × 15-cm spacing reduced GLH numbers (see table). The BPH population increased with N application. K did not influence insect damage or grain yield. Increased gall midge (GM) incidence in plots with intermittent flooding may have been caused by a change in microclimate, and yield reduction may have been caused by hardening of the soil.

Effect of organophosphatic insecticides on the yellow stem borer (YSB) eggs and parasites

N. C. Patnaik and J. M. Satpathy, Entomology Department, Orissa University of Agriculture and Technology, Bhubaneswar 751003, India Insecticides used in rice fields often kill nontarget insect species. We studied the effect of seven insecticides on YSB eggs and egg parasite Telenomus dignoides Nixon (Hymenoptera, Scelionidae). Field


parasitized YSB egg masses were collected in an unsprayed area of the University research farm. In the laboratory, 3 egg masses of uniform size, each attached in situ to a rice leaf, were kept on filter paper in a 7.5 cm-diam petri dish and exposed to the insecticide solution under a Potter's spray tower. After drying, the egg masses were incubated in rearing tubes at 29°C and 55% relative humidity. Each set of three was replicated thrice and an unsprayed set of three egg masses was kept for comparison. Emerged parasites, borer larvae, and unemerged larvae were counted after the unemerged larvae were softened in diluted potassium hydroxide. Treated egg masses yielded a high percentage of parasites and host larvae in all test concentrations. In general, host larva and parasite emergence was significantly lower in the treated set than in the untreated (see table). The varying rate of parasite emergence in the insecticide treatments and the untreated set was caused by the difference in field parasitization rate rather than by the insecticides. Insecticide action on developing parasites

Percent emergence of larvae and parasite adults from insecticide-treated and untreated host eggs at Bhubaneswar, India, Feb 1982. Insecticide

Chlorpyriphos Fenitrothion Fenthion Formothion Phenthoate Phosphamidon Quinalphos

LSD 5%

0.025 0.050 0.075 0.025 0.050 0.075 0.025 0.050 0.075 0.025 0.050 0.075 0.025 0.050 0.075 0.025 0.050 0.075 0.025 0.050 0.075

50.0 57.1 85.7 2.4 48.5 35.7 59.1 76.9 59.0 78.6 52.8 74.1 53.6 26.8 91.0 11.1 60.0 43.3 39.3 44.8 97.7

Common name Striped stem borer Tussock caterpillar Pink stem borer Rice swarming caterpillar Common cutworm Ear-cutting caterpillar Semilooper Rice skipper Yellow stem borer Leaffolder Rice caseworm Rice bug Stink bug Spittle bug Brown planthopper Whitebacked planthopper Leaf rolling weevils Root weevil Rice gall midge Green leafhopper Zigzag leafhopper Aphid Small grasshopper

Eggs (treated)

Eggs (untreated)

10.3 6.0 50.0 11.6 30.1 41.1 45.4 70.9 66.7 60.2 36.0 51.5 47.1 26.0 73.4 17.2 63.6 43.5 25.0 41.3 47.6

32.6 12.2 46.8 20.0 81.3 60.0 12.0 65.0 82.4 63.6 20.0 54.7 66.7 30.0 66.7 28.6 12.0 60.0 77.5 38.5 58.5

2.6 0.8 3.6

and host eggs was adequately circumvented by the hairy matrix surrounding

N. S. Azad Thakur, Indian Council of Agricultural Research Complex for NEH Region, Shillong 793013, India

Adults Eggs (untreated)

32.7 56.0 22.2 24.5 43.8 33.5 22.6 67.6 49.8 43.6 24.4 22.3 77.5 28.0 33.1 16.4 49.5 53.6 19.2 32.7 82.1

Insecticide Untreated vs treated Interaction

Rice insects in the Sikkim hills.


Larvae Eggs (treated)

Insect pests of rice in the Sikkim Hills

Surveys from 1977 to 1981 in hilly rice growing areas in Sikkim identified many insect species (see table). Few insects had pest status. Stem borers Chilo suppressalis (Walk.), Scirpophagu incerfulas (Walk.), and Sesamia inferens (Walk.) were the major pests. They cause 7.2% deadhearts at tillering and 19.5% whiteheads after flowering. Leaffolder Cnaphalocrocis medinalis (Guen.) was a serious pest in Jul 1979, with 22.3 larvae/m2 in Ranipul. Usually it is of minor importance. Brown planthopper Nilaparvata lugens (Stå1) and whitebacked planthopper (WBPH) Sogatella furcifera (Horv.) were generally minor pests, but in 1978 WBPH infestation was high. Gall midge, caseworm, grasshopper, rice bugs, rice hispa, rice leafhoppers, semilooper, spittle bug, leaf beetles, and rice skipper were of minor importance.

Emergence (%)

Concentration (ai %)

2.3 0.7 3.2

the egg mass. The chorion of the egg may also have limited insecticide penetration.

Scientific name

Order

% infestation

Pyralidae Lymantridae Noctuidae Noctuidae

Lepidoptera Lepidoptera Lepidoptera Lepidoptera

7.2 to 19.5 – 7.2 to 19.5 –

S. litura (F.) Noctuidae Mythimna separata (Walk.) Noctuidae Mocis [=Remigia] frugalis (Fabr.) Noctuidae Parnara guttata Hesperidae Bremer & Grey Scirpophaga [=Tryporyza] Pyralidae incertulas (Walk.) Cnaphalocrocis medinalis Pyralidae (Guen.) Nymphula depunctalis (Guen.) Pyralidae Alydidae Leptocorisa sp. Cletus sp. Coreidae Cosmoscarta sp. Cercopidae Nilaparvata lugens (Stål) Delphacidae Delphacidae Sogatella furcifera (Horv.)

Lepidoptera Lepidoptera Lepidoptera Lepidoptera

– – – –

Lepidoptera

7.2 to 19.5

Lepidoptera

–

Lepidoptera Hemiptera Hemiptera Hemiptera Hemiptera Hemiptera

– 12 to 15 – – – –

Centrocorynus scutellaris (Gyll) C. rufulus Voss. Phytoscaphus triangularis (Oliv.) Orseolia oryzae (Wood-Mason) Nephotettix nigropictus (Stal) Recilia dorsalis (Motsch.) Rhopalosiphum padi (Linnaeus) Oxya chinensis (Thunberg)

Coleoptera

–

Chilo suppressalis (Walk.) Euproctis varians (Walk.) Sesamia inferens (Walk.) Spodoptera mauritia (Boisd.)

Family

Attellabidae

Attellabidae Coleoptera Curculionidae Coleoptera Cecidomyiidae Diptera Cicadellidae Homoptera Cicadellidae Homoptera Aphididae Homoptera Acrididae Orthopter

– – – – – – 5 to 8

in 14 Philippine provinces. Telenomus dignus Gahan emerged from 85% of 94 HF egg masses. Eggs collected (6,751) and parasitization percentage (87) were highest in coconut fields followed by maize and rice fields (see table). Tabanus spp. and SB oviposit on the tops of leaves. T. dignus attack both. Although HF eggs are longer and more slender than SB eggs, they are acceptable hosts to the parasitic wasps. HF eggs could maintain T. dignus in fields with low SB populations, and enhance its effectiveness as a natural enemy of SB.

Tabanus (Diptera: Tabanidae) eggs, an alternative host of rice stem borer (SB) egg parasite Telenomus dignus (Hymenoptera: Scelionidae)

A. T. Barrion and J. A. Litsinger, IRRI Telenomus spp. are common egg parasites of Scirpophaga incertulas (Wlk.) and S. innotata (Wlk.) SB in South and Southeast Asia. In 1978-84 we collected the eggs of horn flies (HF) Tabanus spp., which inhabit rice, maize, and coconut fields,

Incidence of parasitization by T. dignus on eggs of Tabanus spp. collected from 14 rice, maize, and coconut provinces in the Philippines, 1978-84. Parasitization Province, municipality

Sampling date

Rice Eggs (no.)

Cagayan Solana Mt. Province Banawe La Union Agoo San Fernando Pangasinan Bani Manaoag Laguna Los Baños

Liliw Santa Rosa Batangas Malvar Tanauan Palawan Aborlan Iloilo Tigbauan Oton

a Dash

on Tabanus spp. eggs Maize

Parasitization (%)

Eggs (no.)

Coconut

Parasitization (%)

Eggs (no.)

Parasitization (%)

23 Sep 1981

510

51

130

84

–

–

27 Mar 1979

115

75

–

–

–

–

13 Oct 1982 14 Oct 1982

106 –

67 –

– –

– –

520 530

65 85

12 Oct 1982 31 Jan 1979

120 –

78 –

– 382

– 78

260 284

81 87

3 Mar 1979 22 Feb 1982 30 Jan 1984 15 Feb 1984 14 Sep 1979 16 Mar 1980

84 – 142 108 – 115

38 – 91 87 – 40

120 356 650 108 – –

85 33 43 78 – –

– – – – 910 –

– – – – 78 –

7 Mar 1979 7 Mar 1979 20 Aug 1980

– 360 98

– 94 50

240 110 340

60 88 64

390 – 650

95 – 17

24 Apr 1979

76

54

–

–

82

100

310 284 81 –

78 66 42 –

285 – – –

44 – – –

1300 530 – 324

96 88 – 100

–

–

4 86

81

–

–

–

–

162

74

–

–

–

–

212

47

–

–

320

50

–

–

–

–

–

–

–

–

484

100

92 3673

82 72

487 6751

85 87

17 21 17 10

Jan 1978 Oct 1982 Jan 1978 NOV 1978

Capiz Dumarao 17 Feb 1981 Agusan Del Sur Del Monte 26 Jul l981 Bukidnon 10 Jul 1979 Pangantukan Zamboanga Del Sur Molave 4 Aug 1981 North Cotabato Kabacan 20 Mar 1980 South Cotabato Koronadal 24 Feb 1983 Total

a

361

88

3190

66

= no eggs collected and no parasitization.

Chironomid, corixid, and ostracod pests of irrigated rice seedling roots

A. T. Barrion and J. A. Litsinger, IRRI We collected several aquatic arthropods in IRRI fields and kept them in glass aquaria to determine if they fed on rice. Two-week-old rice seedlings were suspended on foam sheets with their roots in the water. Three groups of aquatic invertebrates fed on rice roots — larvae (see figure) of seven species of chironomid midges dominated by Chironomus kiiensis Tokunaga, nymphs and adults of a corixid water boatman Micronecta quadristrigata Breddin, and adult ostracod crustacean Cypris sp. We evaluated damage at 0, 20, 40, 100, and 500 arthropods per seedling for 72 h. The corixid cut more root hairs, but damage did not increase beyond 20 adults/seedling. Chironomid and ostracod damage increased progressively with higher densities. Chironomid larvae damaged roots more than ostracods at equal densities. In the field, dapog-raised seedlings are particularly vulnerable to root damage because before transplanting, they grow for 2 wk on banana leaves without soil.

Injury to rice seedling roots caused by chironomid midge larvae (arrow).


Pathogenicity of Beauveria bassiana on brown planthopper (BPH), whitebacked planthopper (WBPH), and green leafhopper (GLH)

R. M. Aguda and J. A. Litsinger, IRRI; and D. W. Roberts, insect pathologist, Insect Pathology Resource Center, Boyce Thompson Institute for Plant Research, Ithaca, New York 14853 B. bassiana is an entomogenous fungus important in microbial insect control. Several strains isolated from BPH, GLH, and WBPH in Asia were bioassayed to determine their virulence on planthoppers and leafhoppers in the laboratory. Spores of each isolate, at 1014/ha, were suspended in sterile distilled water + 0.5% Tween 80 surfactant. Thirty-d-old rice plants were sprayed with the spore suspension at 2 ml/pot, based on a 300litre spray volume/ha, and 20 insects/pot were placed in mylar tube cages. Dead insects were removed daily for 7 d and allowed to incubate for 1 d before microscope examination for infection. Isolates E, RS149, and 101481-5 were the most virulent against all insect species (Table 1). RS149 and 101481-5 had higher virulence to BPH than to GLH and WBPH. BPH was most susceptible to B. bassiana. Isolates RS413, 102381-8C, and E had higher virulence to BPH and GLH than to WBPH. In another test, isolates 102381-8C, GLH-8, and GLH-20 were the most virulent to BPH (Table 2). The other isolates except GLH-1 had moderate virulence. Isolates 102381-8C, GLH-4, and GLH-5 were most virulent against GLH. GLH-20 was more pathogenic to BPH

Leaffolder (LF) outbreak in Haryana, India

K. S. Kushwaha, entomologist; and R. Singh, assistant scientist, Haryana Agricultural University Rice Research Station, Kaul 132021, Kurukshetra, Haryana, India Before 1982 LF Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae) was a minor pest in Haryana, averaging 5-12%


Table 1. Pathogenicity and comparative virulence of different B. bassiana isolates to BPH, GLH, and WBPH in the laboratory, IRRI, 1983. Infectionb (%)

Isolate (I)a RS149 RS413 RS252 102081-2 101481-5 102381-8C E Untreated T-means

BPH

GLH

53 a 36 abc 30 bc 31 abc 49 ab 33 abc 50 ab 0 d

(a) (a) (a) (a) (a) (a) (a)

34 35 29 28 29 29 41 0

35

(a)

28

a a a a a a a

b

WBPH

I-means

(b) (a) (a) (a) (b) (ab) (ab)

16 a 16 a 29 a 18 a 23 a 18 a 26 a 0 b

(c) (b) (a) (a) (b) (b) (b)

34 ab 29 b 29 b 25 b 33 ab 26 b 39 a 0 c

(b)

18

(b)

aRS149

= French strain; RS252, RS413 and BTI Bb = US. strains; 102081-2, 102381-8C, and E from BPH in China; 101481-5 from GLH in China. bIn a column and in a row (in parentheses), means followed by a common letter are not significantly different at the 5% level by DMRT.

Table 2. Pathogenicity and comparative virulence of different B. bassiana isolates to BPH, GLH, and WBPH in the laboratory, IRRI, 1983. Infection b (%)

Isolate (I) a GLH-1 GLH-3 GLH-4 GLH-5 GLH-6 GLH-8 GLH-9 GLH-11 GLH-16 GLH-22 GLH- 19 GLH-20 102081-2 102381-8C Untreated T-means

BPH 14 30 25 20 25 43 34 24 39 24 31 51 29 46 0 29

c abc abc bc abc ab abc abc abc abc abc a abc ab

(a) (a) (ab) (a) (a) (a) (a) (a) (a) (a) (a)

d

(a) (a) (a)

GLH 14 14 40 28 13 20 19 18 18 11 16 11 24 53 0 21

WBPH

c (a) c (a) ab (a) abc (a) c (a) bc (a) c (a) bc (a) c (b) c (a) c (a) c (b) bc (a) a (a) d (ab)

I-means

24 a 15 a 11a 24 a 23 a 33 a 26 a 16 a 25 a 18 a 25 a 25 a 19 a 29 a 0 b

(ab) (a) (b) (a) (a) (a) (a) (a) (ab) (a) (a) (b) (a) (a)

17 c 20 bc 25 bc 24 bc 20 bc 32 ab 26 bc 19 bc 27 bc 18 c 24 bc 29 abc 24 bc 43 a 0 d

20

(ab)

23

aGLH bIn a

1-20 collected from the Philippines; 102081-2 and 102381-8C collected from BPH in China. column and in a row (in parentheses), means followed by a common letter are not significantly different at the 5% level by DMRT.

than to GLH and WBPH, and isolate GLH-4 was more virulent to GLH and BPH than to WBPH. The results suggest

infestation. In 1983 kharif, infestation caused 60-70% leaf damage. Infestation began the first week of Aug and continued to mid-Oct, probably encouraged by heavy rainfall in late Jul (197.9 mm) and Aug (264.l mm). An average 20% damage was observed in Ambala, 27% in Karnal, 29% in Sirsa, and 31% in Kurukshetra. Populations were higher on the late transplanted crop. There were no differences in damage between scented and unscented varieties.

that B. bassiana strains have potential as microbial agents to control BPH, GLH, and WBPH.

Cryptoblabes gnidiella, a fern-feeding caterpillar, and its parasites

Gubbaiah, rice entomologist, All-India Coordinated Rice Improvement Project, V. C. Farm, Mandya, Karnataka, India

In 1983 wet season, Cryptoblabes gnidiella (Millière) were feeding and breeding on azolla in and around the Mandya Rice Research Station. The semi-

Parasitization of azolla caterpillar, Mandya, India. Sep 1983 Wk1 Wk 2 Wk3 Wk4 Mean

Parasitization (%) Apanteles B. sp. excarinata 30 35 43 50 40

8 9 11 14 10

Xanthopimpla sp. 1 1 0 4 1

Wet season population fluctuation of whitebacked planthopper (WBPH) in West Java

Arifin Kartohardjono, Agency for Agricultural Research and Development, Bogor Research Institute for Food Crops, P. O. Box 368, Bogor, Indonesia WBPH Sogatella furcifera Horvath is a serious rice pest in Karawang, where Cisadane is the most popular variety. We recorded WBPH population fluctuations in 1983-84 wet season in Tunggakjati. Biweekly sampling was by sweep net, 25 strokes with 10 replications. Captured insects were observed under a binocular microscope and WBPH and its spider predators were counted. At early growth stages, WBPH population was low and less than the spider population. WBPH population peaked 62 d after transplanting, then decreased. The spider population followed a similar trend (see figure).

aquatic larva forms a tubular structure by folding the azolla and feeds on azolla fronds. Infestation was slight in Jul, but by Sep 40-45% of the azolla was infested with the caterpillars. Well-developed larvae and pupae were collected in the field at weekly intervals to identify natural enemies. Larval parasitization by Apantales sp.

(Braconidae) ranged from 30 to 50% with a mean monthly 40% (see table). The pupal parasite Brachymeria excarinata Gahan (Chalcididae) affected 8 to 14% (av 10%) of the caterpillars. Xanthopimpla sp. (Ichneumonidae) parasitism was about 1%. Caterpillar population declined after Sep because large snail populations killed the azolla.

Parasite complex of yellow stem borer (YSB)

Four egg and four larval parasites were observed (see table). Egg parasitization was greater (47%) than larval parasitization (10%). Tetrastichus schoenobii (Ferriere) was the predominant egg parasite. It peaked with 47% parasitism in Dec-Jan. Apanteles schoenobii (Wilk) was the predominant larval parasite.

N. Chandramohan and S. Chelliah, Tamil Nadu Agricultural University (TNAU), Coimbatore 641003, India We studied the parasite complex of YSB Scirpophaga incertulas (Walk.) from May 1980 to Jun 1982 at TNAU Coimbatore.

Egg and larval YSB parasites at TNAU Coimbatore, India. Parasite Tetrastichus schoenobii Ferriere Telenomus rowani Gahan Telenomus sp. Scelio sp. Exoryza schoenobii Wilkinson Rhaconotus sp. Amauromorpha accepta methathoracica

Family

Host stage affected

Mean parasitism (%)

Month of activity

Eulophidae

Egg

47

Dec-Jan

Scelionidae Scelionidae Scelionidae Braconidae

Egg Egg Egg Larva

6 1 1 10

Oct Jan-Feb Jan-Feb Jan-Feb

Braconidae Ichneumonidae

Larva Larva

3 1

Jan-Feb Sep

Pest control and management WEEDS

Effect of time of herbicide application on rices of different durations

A. M. Ali, Indian Council of Agricultural Research (P. L. 480) – All India Cooperative Rice Improvement Project on Weed Control, Tamil Nadu Agricultural University (TNAU), Coimbatore 641003, India Number of WBPH and spiders at different ages of Cisadane rice in 1983-84 wet season. Karawang, West lava, Indonesia.

We studied in 1983 the selectivity and effectiveness of four preemergence

herbicides in a lowland nursery at TNAU. Soil was a clay loam. Short-duration IR50 (105 d), mediumduration Co 43 (135 d), and long-duration Ponmani (165 d) were the main plot treatments. Herbicides – 1 kg butachlor/ ha, 1 kg thiobencarb/ha, 0.5 kg oxadiazon/ha, and 1 kg pendimethalin/ ha – were applied at 5 and 8 d after sowing and compared to an untreated control. The field was puddled and pre-


Effect of time of herbicide application (DS)a and rice duration in a lowland rice nursery, Coimbatore, India.

Variety

Butachlor 1 kg/ha 5 DS

8 DS

IR50 Ponmani Co 43

0.16 0 0

0.50 0 0.60

Mean

0.05

0.36

IR50 Ponmani Co 43

0.50 0 0

Mean

Thiobencarb 1 kg/ha 5 DS

Oxadiazon 0.5 kg/ha

8 DS

Echinochloa 0 0.33 0

5 DS

8 DS

crus-galli (no./0.04 0.50 0 0 0 0.16 0

Pendimethalin 1 kg/ha 5 DS

m2) at 20 DS 0.50 0.16 0 0.16 0.16 0.33

Control

8 DS

Mean weed data from the nursery

1.16 0.50 1.16

3.50 4.82 4.33

0.94

4.22

0.58 0 1.13

0.11 0.22 0.22 0.22 0 Cyperus difformis (no. /0.04 m2) at 20 DS 0 0.58 0 0.92 0.75 0.16 0 0 0.16 0.75 0 0.25 0 0.08 0.83

1.25 0.93 1.25

4.08 5.08 4.16

0.17

0.57

0.05

1.14

4.44

IR50 Ponmani Co 43

15.7 16.3 16.1

17.7 20.0 18.0

16.3 17.1 17.0

19.2 18.4 20.0

Mean

16.0

18.6

16.8

19.2

0.28

0

0.39

Rice height (cm) 14.2 17.0 17.8 19.6 15.4 18.5 15.8

15.7 17.0 17.2

17.4 18.9 18.5

19.9 19.4 20.0

18.9

16.6

18.3

19.8

111.5 83.0 85.5

122.0 111.5 120.0

136.0 155.5 135.0

93.3

117.8

142.2

IR50 Ponmani Co 43

65.5 78.0 87.5

106.5 121.0 122.5

92.5 118.5 100.0

Rice population 132.5 75.0 106.5 136.0 97.5 149.0 139.5 77.0 138.0

Mean

77.0

116.6

103.7

136.0

aDS

= days after sowing.

1. 2. 3. 4.

83.2

131.2

Varieties

Treatment SE

CD

SE

0.020 0.058 0.570 0.820

0.056 0.163 1.621 2.330

0.011 0.033 0.330 0.474

0.76

Interaction CD 0.032 0.094 0.901 1.340

SE 0.034 0.100 0.984 1.421

CD 0.096 0.283 2.841 4.030

Pest control and management Influence of rate and time of carbofuran application to control root-knot nematodes in upland rice

O. A. Fademi, Nematology Division, Rice Research Programme, National Cereals Research Institute, Moor Plantation, P. M. B. 5042, Ibadan, Nigeria

Root-knot nematode Meloidogyne incognita (Kofoid and White) Chitwood causes poor seedling establishment and low rice yields. The effect is more severe under upland conditions. We tested carbofuran for nematode control in a greenhouse experiment. OS6 seeds were planted in 4 litres of steam-sterilized loamy soil and inoculated


germinated seeds were sown 1 d after leveling. Emulsifiable concentrate formulations were mixed with sand (2 kg/l,000 m2) and applied uniformly in 2.5-cm-deep water. (see table) indicated population of annual weeds in the herbicide-treated plots was from 0 to 0.94/0.04 m2 for Echinochloa crus-galli and from 0 to 1.14/0.04 m2 for Cyperus difformis. Counts were 4.22 to 4.44/0.04 m 2 in control plots. The herbicides effectively controlled weed growth. Eighth-d application was more selective than fifth-d application. Selectivity was low with fifth-d application of butachlor or oxadiazon to IR50.

The International Rice Research Newsletter (IRRN) invites all scientists to contribute concise summaries of significant rice research for publication. Contributions should be limited to one or two pages and no more than two short tables, figures, or photographs. Contributions are subject to editing and abridgment to meet space limitations. Authors will be identified by name, title, and research organization.

OTHER PESTS

with 1000 root-knot nematode eggs recovered from galled roots of Celosia sp. Carbofuran was applied at three rates at

different times (see table) in three replications. Fifty days after planting (DAP), galls and soil nematode population were

Effect of carbofuran on root-knot nematodes in rice, Ibadan, Nigeria. Treatment

No nematicide Carbofuran 10G 1 kg ai/ha Carbofuran 10G 2 kg ai/ha Carbofuran 10G 3 kg ai/ha LSD

a0 = no galling system

1 2 3 4

35 DAP

13 DAP Galling indexa

Nematode population

Galling indexa

Nematode population

2.7 1.3 1.3 1.0

1738 837** 213** 238**

2.7 1.7 1.3 1.7

1738 888** 1475* 250**

1% = 93.78

= less than ¼ of root system with small galls = less than ½ of root system with small galls = less than ½ of root system with medium galls = more than ½ of root system with medium galls

5% = 67.57

counted. Nematode population was determined by thoroughly mixing the soil in each bucket, then taking a 250-cc soil sample for extraction using Baermann's

funnel method. All rates of carbofuran significantly reduced nematode population. Early application of 2 kg ai/ha performed best.

Entomostracan crustaceans inhabiting rice fields

Soil and crop management

S. K. Battish and S. Grover, Zoology Department, Punjab Agricultural University, Ludhiana, India We collected 100 samples of aquatic fauna from the rice fields in and around Ludhiana in 1982 summer, and identified species of Entomostraca. There were 2 conchostracans, 4 cladocerans, 15 ostracods, and 6 copepods (see table). Entomostraca from rice fields at Ludhiana, India. Species Cyclestheria hislopi (Barid)

Caenesthereilla indica (Gurney) Diaphanosoma sarsi Richard Leydigia acanthocercoides (Fischer) Moina brachiata (Jurine) Macrothrix hirsuticornis Norman and Brady Centrocypris bhagirathiae Battish C. madani Battish

Order/Family Order Conchstraca Family Cyclestheriidae Family Cyzicidae

Residual effects of straw, lime, and manganese dioxide amendments on the chemical kinetics of a flooded iron-toxic soil

Li Jin Pei, research fellow, IRRI Fertilizer shortages and high fertilizer prices have encouraged research to determine the residual effect of various amendments applied to improve problem soils. To estimate the beneficial and economic effects of CaCO3 , MnO2 , and straw amendments, we need to know how long the residual effects will persist.

For late application, 3 kg ai/ha is sug gested. There was no phytotoxicity at that rate.

We conducted a greenhouse experiment to determine the residual effects of straw

(2.5 g/kg soil), CaCO3 (2.5 g/kg soil), MnO2 (0.05 g/kg soil) amendments. Soil was collected from the top 20 cm of a Sulfaquept from Malinao, Albay, Philippines. It had pH 3.4, 0.64% organic C, 0.04% total N, 2.4% active Fe, and 0.003% active Mn2+ . Four 3-wk-old seedlings were transplanted in each Pot in 4 replications, and the soil solution was analyzed every 2 wk. Straw and CaCO3 treatment depressed. Eh, EC, Fe2+ , Mn2+ , and SO4 2-

Order Cladocera Family Sididae Family Chydoridae Family Monidae Family Macrothricidae Class Ostracoda Family Cyprididae

Cypris pubera Muller Cypris subglobosa Sowerby Cyprinotus cingalensis Brady Hemicypris derweshensis Battish Hemicypris malerkotlaensis Battish Hemicypris pyxidata (Moniez) Strandesia elongata Hartmann Chrissia sp. Stenocypris major (Baird) Ilyocypris biplicata (Koch) I. bradyi Sars I. dentifera Sars I. gibba (Ramdohr) Eucyclops speratus Class Copepoda (Lilljeborg) Order Cyclopoida Mesocyclops leuckarti (Claus) M. tenuis (Marsh) Microcyclops dentatimanus (Marsh) M. varicans (Sars) Phyllodiaptomus blanci Order Calanoida (Guerne and Richard)

Kinetics of soil solution Fe++ as affected by the different residual treatments, IRRI.


concentrations in the soil solution and increased pH. When the straw was combined with CaCO3, they strongly reduced Fe2+ (see figure) and SO 42- concentrations in the soil solution. The MnO2 treatment gave a high residual level of Mn2+ in the soil solution compared to other treatments, slightly decreased the Eh, EC, Fe2+, SO42contents, and increased the pH of the soil solution compared to the control. Straw and CaCO3 residual effects increased plant height and tiller number up to 4 wk after transplanting (WT) compared to other treatments and the control. Poor plant growth of the control and MnO2 residual treatments was related to high Fe 2+ in the soil solution. At 4 WT, the residual treatment of straw + CaCO3 had lower soil solution Fe 2+ concentrations than the other residual treatments. Plants had greater shoot dry weight and better Fe toxicity scores than in other treatments. At 6-8 WT, the concentration of Fe2+ decreased gradually in MnO2 and control treatments. That caused vigorous plant growth and higher straw and grain yields/ pot than other treatments. However, the differences in grain yields among treatments were not significant (see table).

Response of rice to nitrogen, phosphorus, and zinc in sodic soil

D. K. Sharma and K. N. Singh, Central Soil Salinity Research Institute, Karnal 132001, India

We studied the response of P2-21 to N, P, and Zn application in a barren sodic soil at Gudda Farm in 1980 and 1981. Soil was sandy loam with pH 10.4, 93% exchangeable sodium, 0.22 meq exchangeable Ca + Mg/l00 g, 0.2% total N, 9.8 Olsen’s extractable P, 0.34 ppm DTPA Zn, and adequate available K in the 0-15 cm layer. Gypsum at 13.25 t/ha was uniformly broadcast in 1980 and incorporated at 10-cm depth. Fields had standing water for 15 d before transplanting. Rice was transplanted on 18 Jul in 1980 and 10


Yield of grain and straw of IR26 on an iron-toxic soil, IRRI. Yield a (g/pot)

Treatment

Grain

Straw

1st crop Dried 2 wk presubmergence 4 d 5 c 25 c 21 b 28 c 23 b 38 bc 34 a 55 a 44 a 56 a 45 a 40 abc 41 a 52 ab 41 a

Control MnO2 (0.005%) Straw (0.25%) MnO2 (0.005%) + straw (0.25%) CaCO3 (0.25%) CaCO3 (0.25%) + MnO 2 (0.005%) CaCO3 (0.25%) + straw (0.25%) CaCO3 (0.25%) + MnO 2 (0.005%) + straw (0.25%) Residual amendment

Control MnO2 (0.005%) Straw (0.25%) MnO2 (0.005%) + straw (0.25%) CaCO3 (0.25%) CaCO3 (0.25%) + MnO 2 (0.005%) CaCO3 (0.25%) + straw (0.25%) CaCO3 (0.25%) + MnO 2 (0.25%) + straw (0.25%)

38 a 34 a 31 a 30 a 21 a 22 a 23 a 22 a

2d crop Continuosly submerged

106 a 78 b 48 c 40 c 26 c 28 c 30 c 28 c

a In a column, means followed by a common letter are not significantly different at the 5% level by DMRT.

This experiment showed that the residual effect of the soil treatments, especially CaCO3 and CaCO3 combinations, substantially reduced straw yields, possibly because of exhaustive nutrient uptake by the first crop. The yield in the control, however, increased tremendously after prolonged submergence because

the toxicity constraints were remedied and nutrients were not limited. Prolonged submergence remedied iron toxicity, resulting in increased yields. The negative residual effects of lime and straw amendments on a second crop of rice when the soil is kept submerged has still to be elucidated.

Jul in 1981. P, Zn, and 1/2 N were applied at transplanting. The remaining N was applied in equal splits 25 and 50 d after transplanting (DT). N, P, and Zn were applied as urea, superphosphate, and zinc sulfate. The rice grain and straw yields in all treatments were significantly superior to those of the no-fertilizer control in both

years. In 1980, grain and straw yields did not increase from combined application of N and P or N and Zn over N alone, but yields were significantly higher with N, P, and Zn (see table). In 1981, the yields were significantly higher with N, P, and Zn and N and P. There was also no significant yield difference between N alone and N and Zn.

Yield attributes and grain and straw yield with different fertilizer applications, Karnal, India. Treatment N

P

Zn

0 120 120 120 120

0.0 0.0 0.0 26.8 26.8

0 0 6 0 6

CD (P = 0.05)

Productive tillers/hill

Yield (t/ha)

1000-grain wt (g)

Grain

Straw

1980

1981

1980

1981

1980

1981

1980

1981

6 19 18 18 23

9 19 20 22 26

18 19 20 20 20

19 20 20 20 21

0.6 2.8 3.2 3.0 3.9

1.2 3.7 3.7 4.6 4.7

0.8 3.1 3.4 3.3 4.4

1.6 4.5 4.6 5.4 5.5

0.5

0.2

0.9

0.2

3.9

3.5

1.1

1.9

Effect of blue green algae (BGA) on rice yield at different locations and residual effect on gram

We studied the effect of BGA on rice yields in multilocational trials by the JNKVY ARS in Bilaspur, MP, from 1979 to 1983 (Table 1). Applying 10 kg BGA inoculum/ ha increased grain yield (14%). Table 1. Grain yield with and without BGA, JNKVV.

Location

Control With 10 kg (no BGA) BGA/ha

Sarkanda Khoksa Gorela Ragja

3.4 3.2 2.6 1.1

Barkanda Khoksa Pendra Dharampura

3.4 3.0 2.6 1.5

Sarkanda Khoksa Ragja Lormi Korba Katghora Gorela

2.4 1.7 3.0 2.6 2.7 1.4 2.8

Sarkanda Jali Kudri Janjgir Khisora Khatola Sakti Churi Pali

4.0 1.3 2.2 2.4 3.4 2.4 2.6 3.5 3.4

Bilaspur Bilaspur Mungeli Mungeli Lormi Lormi Pamgarh Pamgarh Katghora Katghora

2.3 2.9 1.8 1.6 3.4 2.9 2.8 1.7 3.5 5.5

Av

2.7

1979

1980

1981

1982

1983

Grain yield (t/ha) Treatment (kg/ha)

G. Ram, Agricultural Research Station (ARS), Sarkanda, Bilaspur, and A. K. Rawat, Jawaharlal Nehru Krishi Vidyalaya (JNKVV), Jabalpur Pin 482004 Madhya Pradesh (MP), India

Grain yield (t/ha)

Table 2. Grain yield with NPK and BGA at 4 locations, JNKVV.

Increase in grain yie1d

t/ha

%

4.1 3.5 3.0 1.1

0.7 0.3 0.3 0.1

19 10 13 7

4.0 3.4 3.0 2.0

0.6 0.4 0.4 0.5

18 13 15 33

2.8 2.0 3.4 3.0 3.0 1.6 3.1

0.4 0.3 0.3 0.4 0.3 0.2 0.3

17 19 11 15 13 16 10

4.6 1.4 2.3 2.5 3.8 2.8 2.8 4.0 3.8

0.7 0.2 0.2 0.2 0.4 0.4 0.2 0.5 0.3

17 12 7 6 12 17 8 14 9

2.8 3.4 2.0 1.8 3.6 3.0 3.2 2.1 4.5 6.3

0.5 0.6 0.2 0.2 0.2 0.2 0.4 0.4 1.0 0.9

20 20 9 14 5 6 14 22 29 16

3.1

0.4

14

1979

1981

Sarkanda

Khoksa

3.4 4.1 – – 4.3 4.4 5.3 –

3.2 3.5 – – 3.2 3.4 4.1 –

1.0 1.1 – – 1.2 1.5 1.6 –

2.6 3.0 – – 3.3 3.8 4.0 –

3.0 3.4 3.3 3.7 3.8 3.8 4.0 4.0

1.7 2.0 2.7 2.8 2.6 2.8 2.6 2.9

23.58 27.58 30.47 30.43 32.57 35.77 39.06 39.29

4.0 4.6 5.3 6.0 5.5 6.2 6.2 6.5

–

0.6

–

–

0.4

0.6

0.4

1.2

Control 10 BGA, 20-40-15 NPK 20-40-15 NPK + 10 BGA 40-40-15 NPK 40-40-15 NPK + 10 BGA 60-60-15 NPK 60-60-15 NPK + 10 BGA CD at 5%

Ragja Pendra Ragja

Trials in 1979, 1981, and 1982 (Table 2) show that applying 10 kg BGA/ ha saves 20-40 kg N/ha. In 1979, we evaluated the yield of Bengal gram planted after rice to determine the residual effect of 10 kg BGA inoculation/ha to rice (Table 3); BGA was inoculated before rice transplanting. Gram was drilled immediately after rice harvest without plowing the field. No fertilizer was applied and the crop was grown without management. Table 3

Yield response of upland rice to NPK fertilization with burned rice husk

A. A. Jakhro, Institute of Agriculture, Timbang Menggaris 102, Kota Belud, Sabah, Malaysia We conducted a field experiment to determine the effect of applying N, P, and K with and without burned rice husk. Soil was a Gleyic Luvisol with 32.1% sand, 36.8% silt, 31.1% clay, pH 5.3, 1.36% organic carbon, 0.18% total N, 37 ppm available P, 0.5 meq exchangeable K/100 Table 1. Weekly rainfall distribution during crop season, Sabah, Malaysia. Mo Jul Aug Sep Oct Nov

1982

Rainfall (mm) Wk1

Wk2

Wk3

85.0 24.1 0 58.4 11.0

12.0 32.0 0 81.1 4.2

18.1 0 68.5 15.6 19.0

Wk4 12.2 43.1 36.0 4.8 41.6

Total 127.3 99.2 104.5 159.9 75.8

Khoksa Sarkanda

Sarkanda

Table 3. Yield of rice and gram after rice, JNKVV. Treatment (kg/ha) Control 10 BGA 40-40-15 NPK 4040-15 NPK + 10 BGA

Rice yield (t/ha)

Gram yield (t/ha)

3.4 4.1 4.3 4.4

1.2 1.8 1.8 1.4

shows that BGA increased rice and gram yield.

g, and 16.74 meq cation exchange capacity/l00 g. Before direct-seeding 120 kg IR42 seeds/ha, 10 t burned rice husk/ha was evenly applied and incorporated. Seeds Table 2. Effect of NPK fertilizer and burned rice husk on grain yield of upland rice, Sabah, Malaysia. Fertilizer applied kg/ha) NPK 0-0-0 50-0-0 100-0-0 150-0-0 0-13-0 50-13-0 100-13-0 150-13-0 0-13-25 50-13-25 100-13-25 150-13-25

Grain yield a (t/ha) With rice husk

Without rice husk 0.9 1.3 1.6 1.9 1.0 2.4 2.6 2.9 1.4 2.6 3.1 3.5 a

ef e

b b

gh

cd c c

fg

i

i

1.5 2.3 2.7 2.9 1.8 3.0 3.9 a 3.8 a 2.8 3.0 3.1

def cd

g

c

c c

i

h

def

3.3 b

a In

a column, means followed by a common letter are not significantly different at the 0.05 level by DMRT.


were sown in rows at 20-cm spacing. Zero, 50, 100, or 150 kg N/ha; 0 or 13 kg P/ha; and 0 or 25 kg K/ha were applied. P and K were applied at planting. N was applied in equal splits 1 mo after sowing and at panicle initiation. The experiment was in a split-plot design with three Effect of different nitrogen applications on rice grain yield

I. U. Awan, H. K. Ahmad, and S. U. D. Gandapur, Faculty of Agriculture, Gomal University, Dera Ismail Khan, Northwest Frontier Province, Pakistan We studied the effect of different N applications on IR6 yield at the Gomal

replications. Weekly rainfall at Timbang Menggaris is shown in Table 1. Rainfall distribution was uneven and interrupted by drought. Yields were low because of low agronomic efficiency of applied fertilizer. Significantly higher grain yields were

obtained with 100-13-0 kg NPK with burned rice husk and 150-13-25 kg NPK without burned rice husk (Table 2). With burned rice husk, high N and K did not increase the grain yield, but results suggest that 10 t burned rice husk/ha supplies 55-3-70 kg NPK/ha to rice.

University Research Farm. Soil was a Zindani series of Entisols with 17% clay, 65% silt, 18% sand, 15.6% CaCO 3, 0.6% organic matter, pH 7.9, 4 ppm available P, 160 ppm K, and 3.5 ppm Zn. Twentyseven kg P/ha as a single superphosphate (9% P) was applied basally, and different levels of N were incorporated in dry soil. Soil was flooded and the field was transplanted.

Results were highly significant. IR6 yielded highest (8.1 t/ha) with 138 kg N/ha as urea (see table). All fertilizer treatments increased yield significantly over the no-fertilizer treatment. Split-Napplication plots yielded less than full application in dry soil, which produced highest straw yield, plant height, panicles/m 2 , 1,000 grain weight, and net return/ha.

Effect of different N applications on rice yield, Pakistan, 1982.

N (kg/ha) Control 46 92 138 46 92 138 92 a Means

a

Yield (t/ha)

Application method – Basal application on dry soil before flooding Basal application on dry soil before flooding Basal application on dry soil before flooding Equal splits on dry soil before flooding and 7-8 wk after transplanting Equal splits on dry soil before flooding and 7-8 wk after transplanting Equal splits on dry soil before flooding and 7-8 wk after transplanting Conventional (30+31+31)

Grain

Increase (t/ha) over no-fertilizer

Net return b (US$/ha)

Plant ht (cm)

Panicles (no./m2 )

1,000-grain wt (g)

Straw

Grain

Straw

10.6 c 11.8 bc

– 0.8

– 1.2

– 54.3

86.7 87.1

422 436

25.3 27.3

7.3 ab

14.3 ab

2.0

3.7

137.7

91.3

467

28.3

8.1 a

15.2 a

2.8

4.6

192.0

98.1

510

30.0

7.1 bc

13.6 ab

1.8

3 .0

140.0

90.0

483

27.3

6.8 bc

14.7 a

1.5

4.1

94.8

92.1

4 86

27.7

6.8

12.8 abc

1.5

2.2

78.0

87.4

486

28.0

1.7

4.4

109.4

91.3

458

27.3

5.3 6.1

d cd

bc

7.0 bc

15.0 a

followed by similar letters are not significantly different at the 5% level. b Rice = $86/t; urea fertilizer = US$8.5/23 kg N.

Effect of bio, organic, and chemical fertilizers on rice grain yield

A. Saravanan and K. M. Ramanathan, Tamil Nadu Rice Research Institute (TNRRI), Aduthurai 612101, India

We studied the effect of combined application of bio, organic, and chemical fertilizers on IR20 grain yield at TNRRI in Aug-Jan 1983. Soil was an alluvial clay loam with 137 ppm available N (alkaline permanganate method), 35 meq CEC/100 g, and pH 6.6.


The experiment was in a randomized block design with three replications. Forty kg PK/ha was applied with 60 or 90 kg N as urea, farmyard manure (FYM) 0.609% N, green manure (Gm) 0.518% N fresh weight, and azolla 0.395% fresh weight. Fertilizers were incorporated 1 wk before transplanting. N application increased grain yield significantly over the control (see table). At 60 kg N, urea alone performed better than in combination with organic manures. At 90 kg N, urea + azolla performed better than urea alone. At both N levels combinations with azolla performed best.

Effect of bio, organic, and inorganic fertilizers on grain yield, Aduthurai, India. Treatment (kg N/ha)

Grain yield (t/ha)

Control 30 as urea + 30 as FYM 30 as urea + 30 as Gm 30 as urea + 30 as azolla 60 as urea 45 as urea + 45 as FYM 45 as urea + 45 as Gm 45 as urea + 45 as azolla 90 as urea

3.5 3.8 4.1 4.2 4.3 4.3 4.6 5.1 4.9 0.4

CD

Rice-based cropping systems Groundnut varieties for summer rice fallows

K. Pushkaran and V. Gopinathan Nair, Kerala Agricultural University, Trichur, Kerala, India

In 1980 we evaluated 93 groundnut varieties for cultivation in summer rice fallows at the Mannuthy Agricultural Research Station. All the varieties established satisfactorily, and 31 were selected for further evaluation in comparative yield trials (Table 1). Duration to maturity ranged from 95 d for Exotic 6 to 117 d for M-13. ICG3859 had the highest fresh haulms yield, 20 t/ha; followed by S-7-5-13, 17 t/ha; and AH6915, 17 t/ha. TG3 ranked first in pod yield with 3.2 t/ha. The recommended varieties TMV2 and TMV7 yielded only 2 t/ha. None of the promising varieties were damaged by pests. Based on yield and other desirable characters, six varieties and two check varieties were chosen for multilocation testing in farmer fields at five sites. Tests were in a randomized block design with three replications. In pod yield TG3 was best, followed by TG14 and Spanish Improved (Table 2). TG3 and TG14 are bunch varieties evolved at the Biology and Agriculture Division, Bhabha Atomic Research Centre, Bombay. TG3 is an x-ray induced mutant and TG14 is a derivative of a cross between two mutants from the same Spanish Improved. The two varieties have been approved by the Variety Evaluation Committee of Kerala Agricultural University for large-scale cultivation.

Table 1. Pod yield and other important characters of 31 selected groundnut varieties, Kerala, India.

Variety EC21118 ICG3859 EC36892 S-7-5-13 EC112027 B353 EC35999 EC119704 AH6915 M-13 Spanish Improved Dh-3-30 Jyothi Exotic 6 TMV9 TMV 10 AK-811 TMV2 KG6 1-240 TMVll Pollachi-2 TG3 TG 14 TG17 TG19 Pollachi 1 TMV7 Gangapuri Big Japan Co 1 JL 24 CD (0.05)

Duration (d)

Fresh haulms yield (t/ha)

Dry pod yield (t/ha)

101 105 111 112 96 106 99 112 113 117 99 98 98 95 100 106 102 107 99 109 97 99 106 101 98 100 98 98 110 106 99

15.4 20.5 14.2 16.9 13.3 9.0 13.7 12.2 16.6 13.4 14.3 14.4 13.1 16.2 9.4 14.8 14.3 9.1 12.5 9.3 15.1 14.9 11.3 11.3 12.8 11.5 14.1 16.3 11.7 7.8 7.4

2.3 2.6 2.9 2.5 2.9 1.9 2.9 2.6 2.5 2.4 3.1 2.7 2.6 2.6 2.9 2.6 2.7 2.4 2.6 2.5 3.1 3.2 3.1 2.5 2.7 2.9 1.8 1.5 2.5 2.7 2.5

2.7

2.91

0.434

100-pd wt (g)

Shelling (%)

Oil content (%)

Protein content (%)

78 67 70 61 78 76 75 69 67 69 73 73 76 78 75 71 78 75 81 72 78 73 71 71 73 69 77 69 57 76 74

46 49 43 54 47 49 47 47 53 42 48 49 50 48 47 52 48 47 47 43 46 47 47 49 48 45 48 49 48 50 48

25 25 29 26 23 26 26 28 27 30 26 25 26 27 26 23 27 25 25 25 25 24 26 29 26 25 25 26 28 26 28

82 110 142 103 90 83 101 113 140 107 91 87 103 78 88 88 86 108 71 125 83 99 102 121 92 113 84 92 98 90 108 1.4

1.1

0.7

1.1

Table 2. Dry pod yield of selected groundnut varieties in multilocation trials at 5 sites, Kerala, India.

Variety TG14 Spanish Improved TG3 Pollachi 2 EC35999 TMV2 TMV7 JL 24 CD (0.05)

Dry pod yield (t/ha) Mannuthy

Puthur

Kodassery

Puthukod

Malampuzha

Mean

2.42 2.17 2.56 2.43 2.41 1.91 1.98 2.19

2.26 2.37 2.61 2.26 2.25 2.08 1.88

2.50 2.37 2.97 2.31 2.38 2.19 2.50

2.23 2.39 2.51 2.26 2.29 1.93 1.85

2.95 2.33 3.07 2.43 2.27 2.35 2.07

2.47 2.33 2.75 2.34 2.32 2.09 2.05 2.19

0.111

0.225

0.258

0.143

0.242

0.267

The International Rice Research Newsletter (IRRN) invites all scientists to contribute concise summaries of significant rice research for publication. Contributions should be limited to one or two pages and no more than two short tables, figures, or photographs. Contributions are subject to editing and abridgment to meet space limitations. Authors will be identified by name, title, and research organization.
