international rice research newsletter vol.9 no.6

8/4/2019 International Rice Research Newsletter Vol.9 No.6

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Contents

GENETIC EVALUATION AND UTILIZATION

Disease resistance3 Characterizing adult plant resistance to bacterial blight (BB)

6 Performance of HKRl0l under bacterial blight (BB) stress

Insect resistance

7 Reaction of rice cultivars to pink stem borer (PSB)

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

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

8 Reaction ofyellow 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 India10 Rice yield loss to sheath blight (ShB)

10

11 Bacteriophage strain of Xanthomonas campestrispv. oryzae from parts of

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

Thailand

Insects

14 Inheritance of virulence of the North Sumatra population of the brown

15 Possible genetic isolation between theLeersia and rice brown planthopper

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

16 Relationship between biochemical characteristics of rice and establishment

planthopper (BPH) on IR42

(BPH)

Sumatra

of yellow stem borer (YSB) larvae

16 Inhibitory effects of insecticides on entomogenous fungi Metarrhizium

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

17 Effect of organophosphatic insecticides on the yellow stem borer (YSB)

18 Insect pests of rice in the Sikkim Hills

19 Tabanus (Diptera: Tabanidae) eggs, an alternative host of rice stem borer

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

20 Pathogenicity of Beauveria bassiana on brown planthopper (BPH)

whitebacked planthopper (WBPH), and green leafhopper (GLH)

20 Leaffolder (LF) outbreak in Haryana, India

20 Cryptoblabes gnidiella, a fern-feeding caterpillar, and its parasite

21 Wet season population fluctuation of whitebacked planthopper (WBPH)

21 Parasite complex of yellow stem borer (YSB)

anisopliae and beauveria bassiana

eggs and parasites

(SB) egg parasite Telenomus dignus ( Hymenoptera:Scelionidae )

in West Java

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

23 Entomostracan crustaceans inhabiting rice fields

nematodes in upland rice

SOIL AND CROP MANAGEMENT

23 Residual effects of straw, lime, and manganese dioxide amendments on the

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

25 Effect of blue green algae (BGA) on rice yield at different locations and

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

26 Effect of different nitrogen applications on rice grain yield

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

chemical kinetics of a flooded iron-toxic soil

residual effect on gram

RICE-BASED CROPPING SYSTEMS

27 Groundnut varieties for summer rice fallows

Yield loss to bacterial blight (BB) in central Thailand


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Guidelines and Stylefor

IRRN Contributors

Articles for publication in the International Rice

Research Newsletter (IRRN) should observe thefollowing 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.).

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

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 namesnot trade namesfor

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 acronymthroughout 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 ina table or figure.

bibliography.

Abbreviate names of standard units of

(g/ pot) or g/row.

Do not cite references or include a

Genetic evaluation and utilizationDISEASE RESISTANCE

Characterizing adult plant resistance to

bacterial blight (BB)

Zhang Qi and T. W. Mew, IRRI

1. Adult plant resistance of selected

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 campestrispv.

oryzae differed with growth stage. All

cultivars were very susceptible as seed-

lings 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

Chinese cultivars

2.2 at booting. Growth stage did not

affect the response of Shi-zu and of sus-

ceptible check TN1 to the four races.

Reaction patterns of adult plant

resistance. Among the cultivars with

adult plant resistance, two disease devel-

opment 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).

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

1984.

Variety

Guai Zhou Magu Nangen 11Peng Chiu Moung

Nangen 15Kwang-er-ai 5Taichung Sen 53330

Chin Kong Tao3

Wan Mi HsiangShi-zu

TN1IR1545-339

Resistancea to given race

PXO 6 1 PXO 86 PXO 79 PXO 71

SS MTS BS SS MTS BS SS MTS BS SS MTS BS

8.5 5.5 1.0 8.5 3.1 1.1 8.0 5.2 1.0 7.0 5.0 1.46.5 4.0 1.0 6.3 3.0 1.0 6.5 3.3 1.0 6.0 3.5 1.06.5 3.1 1.2 6.1 1.3 1.0 6.0 3.0 1.0 6.2 3.2 1.06.7 5.5 2.0 6.5 3.0 1.7 6.5 5.6 2.8 7.0 5.1 1.08.5 6.2 2.7 6.5 5.0 1.5 9.0 7.0 2.7 9.0 7.0 2.87.0 4.7 3.0 7.5 4.7 2.0 9.0 5.4 3.0 8.0 4.3 3.07.5 5.7 3.5 6.7 3.3 1.6 7.2 5.4 2.7 7.2 5.5 4.0

7.0 4.3 3.5 6.7 3.7 1.7 6.7 4.8 1.2 7.3 6.6 6.89 5.4 4.7 7 3.0 1.3 8.5 5.0 5.0 9 6 5.01.0 1.3 1.0 3.0 1.0 1.0 2.5 1.3 1.0 1.0 1.2 1.01.8 3.0 1.0 3.5 3.0 1.0 3.2 2.0 1.0 6.8 5.0 6.09 8.0 6.8 9 6.7 4.3 9 7.3 6.3 9 7.3 7.0

a By the 1980 Standard Evaluation System for Rice scale. SS = seedling stage, MTS = maximumtillering stage, BS = booting stage.

IRRN 9:6 (December 1984) 3


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1. Reactions of 3 rices to the 4 BB races from6th to flag leaf. IRRI, 1984.

2. Greenhouse testing ofXa 6and 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 6gene for BB

resistance. Wase Aikoku 3 has theXa 3

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)

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 devel-

oped 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).

ance only to races 1, 2, 4, and wasresistant to race 3 at all leaf positions

(Fig. 2).

Wase Aikoku 3 had adult plant resist-

3. Reactions of Zenith and Malagkit Sungsonginoculated with 4 BB races at the same time.IRRI, 1984.

3. Influence of temperature on the Xa 6

gene for BB adult plant resistance

High temperature favors BB development

but it is not known whether adult plant

resistance controlled by the Xa 6gene is

stable in high temperature.


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We evaluated BB resistance of Zenith,

M. Sungsong, IR1695, and IR944 at

33-25, 29-21, and 25-20C ranges in

growth chambers with 70% relative

humidity. The four cultivars have the

Xa 6gene.

Zenith and M. Sungsong resistance

was unaffected by temperature changes.

However, resistance by leaf position wasnot consistent with greenhouse obser-

vations. 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 25-20C than at 29-21C.

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. Bacteriophage method for estimating

Temperature affected BB development

X. campestris pv. oryzae multiplication

in infected rice leaves

Taking direct counts of X. campestrispv.

oryzae cells by plating on ordinary media

is impossible because the bacterium is

slow growing and subject to contamina-

tion, 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 patho-

gen 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

4. Disease reactions of Zenith to BB races at 5. Disease reactions of Malagkit Sungsong to

3 temperature ranges. IRRI, 1984. the 4 BB races at 3 temperature ranges.IRRI, 1984.

6. The titration curve of bacterial densitywith a standard phage concentration.IRRI, 1984.

plated on PSA medium. The rest was

mixed with a standard phage concen-

tration.

Ten minutes after incubation at 28C

in aeration, the mixture was centrifuged

7. Relationship between phage count(PFu/cm2) and colony (CFu/cm2) atdifferent leaf positions of Zenith with BBlesions. IRRI, 1984.

to remove the excess phage. The preci-

pitate was resuspended and incubated for

20 min to estimate phage absorption by

the bacterial cells. Final phage plating

was 10 h after incubation. The correla-

tion between viability count for bacteria

and phage count as an indication of

bacterial multiplication is shown in



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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 6gene 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 multipli-

cation 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 develop-

ment 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 12thleaf, 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 plaque-

forming units/cm2 leaf area, on leaves 6,

9, and 10 increased 24 HAI, indirectly

8. BB lesion development on different leaf positions of Zenith in the greenhouse.IRRI, 1984.

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. oryzaeon leaves 6, 9, 10, and 12 of Zenith estimated by the phage method. IRRI, 1984.

Individuals, organizations, and media areinvited to quote or reprint articles or

excerpts from articles in the IRRN.

Performance of HKR101 under bacterial Whole plots were inoculated 30 d after though HKR101 was as susceptible to BB

blight (BB) stress transplanting by cutting 5 cm from leaf as the check varieties, it yielded 16% more

tops with a sickle dipped in inoculum. (see table). HKR101 has better grain

R. Pal, A. Singh, D. V. S. Panwar, and

S. C. Ahuja, Haryana AgriculturalUniversity (HAU) Rice Research Station,

Kaul 132021, Haryana, India

HKR101 is a medium-duration semidwarf

rice with long bold grains. It was devel-

oped at HAU Rice Research Station. We

evaluated artificially inoculated HKR101

Inoculum was prepared by soaking 1-cm quality than Jaya or PR106, and equal

pieces of infected leaves for 20 min. Al- milling recovery.

Performance of HKRl0l under BB stress, Haryana, India.

BB Yield (t/ha)Duration

Pani- Kernel Kernel Length- Milling

tiona 1980 1981 1982 1983 Mean m2 (mm) (mm) ratio (%)

Variety reac-(d)

cles/ length breadth breadth recovery

HKR101 9 5.0 6.0 4.9 3.7 4.9 144 306 7.3 2.5 2.9 66Jaya 9 4.4 4.9 4.1 3.2 4.2 146 281 6.6 2.6 2.6 66PR106 9 4.3 5.1 4.4 3.0 4.2 147 292 7.1 2.1 3.4 66

for BB resistance in a replicated trial from CD at 5% .8 .9 1.1 .4

1980 to 1983. Check varieties were JayaCV % 11.12 10.7 15.97 7.03

and PRl06. a IRRI Standard Evaluation System for Rice.



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Insect resistance

Reaction of rice cultivars to pink

stem borer (PSB)

D. K. Garg, Vivekananda Laboratory for

Hill Agriculture, Indian Council ofAgricultural 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-

eries that were screened at Hawalbagh

in 1980. VL 8 and China 1039 were the

resistant and susceptible checks.

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% infesta-

tion), 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).

Pest incidence was heavy from Sep-Oct

Varietal resistance to PSB, Hawalbagh, India.

Reaction Cultivars

Resistant HPU803, HPU2199,

(0-5%) IR9129-192-24-3,IR9758-150-3,IR19774-34-2-1,

KAU 2110, VRS163-2-3VRS291-3-1, VL8(resistant check)

(5.1-10%) IR2053-521-1-1,Moderately resistant ARC11981, Fuzi 102,

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

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 andTechnology, 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

genes. The F1 and F2 populations were the F2 plants segregated as 3 susceptible

evaluated for WBPH reaction by bulk 1 resistant. In the cross Balamawee/

screening (see table) ARC10464, the F 1 plants were suscep-

Resistance in each of Balamawee and tible and the F 2 segregated as 9 sus-

ARC10464 is governed by a single ceptible: 7 resistant, indicating that the

recessive gene. In both the crosses with recessive genes for resistance in both

TN1, the F1 plants were susceptible and varieties are nonallelic.

Reactiona of F1 and F2 populations to WBPH, Pantnagar, India.

F2 reaction

Cross F1

reactionTotal

Assumed

(no.)R (no.) S (no.) genetic X2 P value

ratio

TN1/Balamawee S 137 39 98TN1/ARC10464

1:3S

0.88 0.50-0.30136 40 96

Balamawee/ARC104641:3

S 189 77 112 7:9 0.56 0.50-0.301.41 0.30-0.20

aS = susceptible, R = resistant.

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 ResearchStation (ARS), Warangal 506007, India

In the northern Telangana region of

Andhra Pradesh, uncertain monsoon

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 recom-

mended. Each panicle has about 170

long, slender, translucent grains. Seed

IRRN 9:6 (December 1984)


8/28

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 defi-

ciency in the field at Pusa beginning in

1981 wet season. The first trial was non-

replicated. 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 mod-

erately tolerant entries were photoperiod

sensitive and are pureline selections from

land races.

B. N. Singh, senior rice breeder; and B. P.

Singh, junior scientist, Rajendra Agri-cultural University, Bihar, Pusa,Samastipur 848125, India

Fe deficiency is a major constraint to in-creasing 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

CaCO3 , and low available P. Nurseries are

dry-seeded and seedling leaves whiten in

the nursery beds. Fe deficiency

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 photoperiod-

insensitive with 125-d duration in mon-

soon and 135 d in winter. Grains are

translucent. It has stem borer (SB) and

bacterial blight resistance, and yields WGL 20506 (Tella Hamsa/W12708)

6.0 to 7.5 t/ha. It is recommended for has 105-d duration and is especially suite

release as Pothana. for sowing in late monsoon, as late as

WGL 26889 (IR22/12708) is a 145-d mid-Aug. Grains are long and slender

variety suitable for the monsoon season. with a light brown husk. Yield averages

It is SB-resistant with fine grains, and 4.5 to 5.0 t/ha.

yields an average 6.0 t/ha. It is being

tested in minikit trials.

Reaction of yellow stem borer (YSB)

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 plant-

hopper (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

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

Mean resistance rating a

Accession

YSB GLH WLH BPH WBPH LF RTV b

W1263 1.0 a 4.3 a 1.8 a 5.0 aCo 18

4.0 a 6.3 bc 3.6 a4.0 bc 6.0 ab 3.6 a 3.6 a 3.6 a 6.2 bc 7.6 c

IR13641-4 4.0 bc 7.0 bc 6.3 bc 7.6 cd 5.0 ab 6.6 c 7.0 bcIR13639-39 4.0 bc 5.6 ab 5.6 b 5.6 b 5.0 ab 5.4 b 5.0 aSornavazhai 6.5 c 7.0 bc 7.6 cd 3.0 a 4.3 a 9.0 d 7.0 bcJaya (susceptible) 9.0 d 6.5 abc 5.0 ab 7.0 bcTN1

6.3 ab 9.0 d 9.0

a

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

9.0c 9.0 d 9.0 d 7.6 b

IR13639-39 were moderately resistant to moderately susceptible to other pests.

BPH, WBPH, and WLH. IR13641-4 was Sornavazhai was resistant to BPH and

moderately resistant to WBPH and WBPH.


Adverse soils tolerance

Tolerance for iron deficiency in rice

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

Tolerance Plant

score infection (%)

Line

1 up to 1 IET7972 (TCA148-3), IET7973 (TCA62-31-1)3 1 5 Br34, Br8, TCA84

5 5 25 UPR238-42-2-3, IET5882, UPR79-17, T141,

7 25 50 Rasi (IET1444, Pankaj, Janaki (IET9971),

9 50 100 Pusa 33, Pusa 2-21, Ratna, Rajendra Dhan 201,

NP49, IET6263

IET7970, KMP40, IET5883

Sita, Jaya, Mahsuri, Saket 4, Radha (IET6261),

IR1157-52, UPR254-81-1-TCA, Br9, Katarni

UPR79-14, IR4568-86-1-2-3, RP1045-403-1,



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Total Fe content in the leaves of tol-

erant and susceptible lines was unrelated

to deficiency symptoms (Table 2). How-

ever, orthophenanthroline reactive Fe2+

content of the leaves appeared to be

related with deficiency symptoms. Lines

with less than 30 ppm orthophenanthro-

line reactive Fe2+ in the upper leaves

were more susceptible than those with30 to 40 ppm Fe 2+. Lines with more

than 40 ppm Fe2+ were tolerant.

Dry matter accumulation was signifi-

cantly and positively correlated with

orthophenanthroline reactive Fe2+ (r=

0.90**).

Table 2. Total dry matter content, Fe, and orthophenanthroline reactive Fe2+ in upper leaves of ricgenotypes, Samastipur, India.

EntryDry matter

yield

(g/20 plants)

Total Fe

(ppm)

Orthophenanthroline

Fe2+

(ppm)

IET7973 6.7 240 50IET7972 6.3 255 42IET5882 6.0 260 37Pankaj

3.4 375 33IET6263 5.2 450 36Pusa 33 3.1 490 32Mahsuri 2.6 337 28Saket 4 2.7 288 30T141 3.6 500 33

Pest control and management DISEASES

Effect of planting date on rice tungro

virus (RTV) infection

B. N. Singh, senior rice breeder; andY. Prasad, senior scientist, Rajendra

Agricultural University, Bihar, Pusa848125, 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 andattained 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 random-

ized block on 25 May, 9 Jun, and 24 Jun

1980 and 30-d-old seedlings were trans-

planted in 20- 15-cm spacing in 7.5-m2

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.

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 Ratnawere 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.

Only RP967-11-1-4-2-2 was infected

RTV infection of varieties planted at different

dates at Pusa, India.

RTV reactiona

25 May 9 Jun 24 JunEntry

Pusa 33Pusa 2-21Govind (UPR82-1-7)Saket 4 (CR44-35)RatnaPrasadJayaIR8SitaRajendra Dhan 201BG90-2SPR7284-57-5RP967-11-1-4-2-2Pankaj

MR1RP975-109-2 (IET5656)

1 1 11 1 11 1 71 1 11 1 11 7 91 7 91 7 91 7 91 1 51 9 91 1 97 7 91 1 71 1 51 7 9

aBy the 09 scale of the 1980 Standard Evalua-tion System for Rice.

A new rice virus disease in India

V. Mariappan, H. Hibino, and

N. Shanmugam, Tamil Nadu AgriculturalUniversity, 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

tungro virus (RTV). Plants had mild

stunting and increased tillering. Brown

planthopper (BPH) was in the fields.

Infected plants were collected and trans-

mission tests were conducted by using

the green leafhopper (GLH) Nephotettix

virescens Dist. and BPHNilaparvata

lugens Stl.

acquisition access feeding on source

plants were transferred to 10-d-old TN1

Virus-free GLH adults given 4-d

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 virus-

free BPH colony were released on source

plants for 7-d acquisition access feeding,

and then collected and released on 10-d-

old TN1 seedlings at 2 insects/plant for

10-d inoculation access feeding. The

inoculated plants developed yellow-

IRRN 9:6 (December 1984)


10/28

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 driedleaves reacted positively up to 1:8 dilu-

tion; 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).

as a strain of GSV. It is similar to GSV

strain 2 in the Philippines. So far there

are no reports from India of BPH-

transmitted leaf yellowing.

We therefore identified the new disease

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

InsectTN1 O. nivara

Inoculated Infected Inoculated Infected

N. virescens 25

N. lugens 610

196

1809

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

Undiluted 2 4 8 16 32 64 128 256 512Sample

Dried TN1 leaf infected with

Fresh TN1 leaf infected with GSV + + + + + + + + + +Fresh TN1 leaf free from virus

+ + + +

new virus

+ = positive, = negative.

Rice yield loss to sheath blight (ShB) inoculated at tillering by inserting a

packet of mycelia and sclerotia ofT.

P. Arunyanart, A. Surin, cucumerisin each hill. Validamycin wasW. Rojanahasadin, R. Dhitikiattipong, used to keep disease intensity at the

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 infesta-

tion to determine an economic threshold

at which to apply chemical controls. The

experiment was in a randomized com-

plete block design with 4 replications of 5

treatments of different disease intensi-

ties: 0, 3, 5, 7, and 9 by the Standard

Evaluation System for Rice. RD7, the

most ShB-susceptible variety, was trans-

planted in 6- 4-m plots and artificially

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).

Yield loss to bacterial blight (BB) in

central Thailand

W. Sirisantana, N. Nilpanit, S. Phawichit,

P. Kiatsuranont, and S. Disthaporn, RicePathology Branch, Plant Pathology and

Microbiology Division, Agriculture

Department, Bangkhen, Bangkok,

Thailand

Relationship between lesion length and per-centages of yield loss, straw weight loss, and BB, caused by Xanthomonas campestrisempty grains. Bangkhen, Thailand. pv. oryzae, is a serious constraint in parts

Rice yield characters affected by different ShB severity, Bangkhen, Thailand. We studied yield loss caused by BB at

of Thailand.

Bangkhen Rice Experiment Station inEmpty 1983 rainy season. RD1, a susceptibleAv Yield Av 100-grain

Disease index yield reduction straw wt wt

(kg/8 m) (%) (kg/8 m) (g) (%)rice cultivar, was transplanted in 4 of 510-m2 plots. Ammophos 16-20-0 was

0 4.05 a 0 a 26 a 3.0 a 21 a

3 3.42 b 15 b 24 ab 3.0 a 24 btopdressed at 250 kg/ha, and plants were

5 3.10 bc 22 bc 21 b 2.9 a 26 bfully protected from other diseases and

7 2.88 c 28 c 18 c 2.9 ab 30 cinsect pests. Every hill in alternate rows

9 2.39 d 40 d 15 c 2.6 b 33 dwas clip-inoculated at midtillering. When


grain


11/28

Yield from rice with different intensities of BB

at booting and milk stages, Bangkhen, Thailand.

Disease Grain wt (g) Empty grainintensitya (%)

(%) Booting Milk Booting Milkstage stagestage stage

0 33.9 49.5 8 80-5 33.5 47.9 17 9

5-10 32.8 51.8 10 910-15 30.5 48.9 9 815-20 25.2 42.5 16 1020-25 31.9 50.0 15 1225-30 b 51.3 b 12

a % disease severity in hill =sum of % BB severity on flag leaves

and 2d leavesnumber of tillers in hill 2

b = no information.

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

Bacteriophage strain ofXanthomonas

campestris pv. oryzae from parts of

Thailand

N. Nilpanit, W. Sirisantana,

P. Kiatsuranont, S. Phawichit, andS. 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) out-

break. 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 bac-

terial isolates that are susceptible to

phage strains in areas where the bacterio-

phage 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).

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

Bangkhen, Thailand.

disease severity. At milk stage, percentage implied that increasing disease intensity

of empty grains was significantly related increased percentage of empty grains.

to different disease intensities (see table). Because yield component analysis waThe correlation of empty grains and based on data from individual hills and

disease intensity was calculated as a because of the human influence, a high

simple linear regression equationy = C. V. was noted. Therefore, grain weigh

8.2369 + 0.1306X** (see figure), which did not correlate with disease intensity

Forty X. campestris isolates were isolated

from infected leaves using Wakimotos

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.

single plaques that developed 15-20 h

later to test tubes containing a vitamin-

free casein hydrolysate solution. Dif-

ferent lysotypes were determined bytesting all bacteriophage samples against

all bacterial isolates.

To maintain the phage, we transferre

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

Province Region X. campestris strain Phage straina

Lampang Northern BPichit Northern B Petchaboon Northern ESinghaburi Central BAungthong Central HChainat Central A, B, E TBP1, TBP4, TBP5Suphanburi Central B TBP2Bangkok Central A, B, C, D, E

Pathumthani

TBP1, TBP3, TBP

Kanchanaburi Central AKhon Khaen Northeastern A, C, F, G TBP3Mahasarakarm Northeastern B TBP 3Kalasin Northeastern A, E TBP 3, TBP5Sakonnakorn Northeastern D, EUdonthani Northeastern D, E TBP5

Nongkai Northeastern D 5 Nakornsajsima Northeastern A, C, TBP3Buriram Northeastern F

PhatalungTBP 3

aA dash means not found.

Central BTBP1, TBP4

Southern E



12/28

Twenty-two X. campestrisbacterio-Table 2. Classification ofX. carmpestrispv. oryzae based on bacteriophage sensitivity in Thailand.

phages were classified as having five phage

strains: TBP1, 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 TBPl and TBP2 were

the most widely distributed, and bacterial

strain A was most susceptible to all phagestrains. 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).

BacterialPhage strain

strain TBPl TBP2 TBP3 TBP4 TBP5

Bacterial isolates obtained

A + +

B + +

C +

DE

FGH

+ +

+

+ +

+

+

+

+

+

TB 8206, 8208, 8209, 8234, 82028212, 8214, 8216, 8218, 8230

TB 7536, 8004, 8104, 8204, 82058211, 8221, 8236

TB 8210, 8227, 8228, 8233

TB 8203, 8222, 8223, 8225, 8226TB 8201, 8207, 8213, 8217, 8219

8224, 8235, 8301TB 8215, 8231, 8232TB 8229TB 8003

Nitrogen fertilization and sheath rot (SR)

development in rice

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

sail, a local improved variety. Recom- domized complete block design with 4-

mended cultural practices were followed, 3-m plots and raised levees.

including 65 kg P and 45 kg K/ha at At early booting, all tillers of 10 ran-

final land preparation. Urea N was applied domly selected hills/plot were inoculatedin equal splits at tillering and panicle ini- with S. oryzae cultured on sterilized rice

tiation. The experiment was in a ran- grains. The grain inocula were pushed

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.

SR, caused by Sarocladium oryzae, was

identified in Bangladesh in the early

1970s. It has become a constraint to N-

responsive modem varieties (MV).

We studied the effect of 0, 30, 60, 90,

and 120 kg N/ha on SR severity in trans-

planted aman BR11, an MV, and Nizer-


13/28

partly into the middle portion of the flag no infection and 9 indicated complete increased DI in both varieties (Fig. 2).

leaf sheath and held there with scotch flag leaf sheath discoloration and un- The regression coefficient (b) in both

tape. At maturity, disease intensity (DI) emerged panicles (Fig. 1). varieties was equal, indicating a similar

was rated using a 0-9 scale. Zero indicated Increasing N application significantly trend.

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 30N. virescens per plant to

test their reaction to RTV complex. The

insects were allowed 4-d acquisition

access time on plants infected with bothrice 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 in-

creased in IR36 and IR42 when viruli-

ferous 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 tRTSV infection (see table).

Percentage infection of IR varieties when ino

ulated with RTSV at 1 insect/seedling, IRRI.

Inoculated Infected seedlin

Variety seedlings

(no.) No. %

IR36 36 21 58.3IR42 38 15 39.4IR50 38 6 15.7IR54 38 8 21.0IR56 39 32 82.0

TN 1 102 85 83.3

Reaction of IR varieties to RTV complexwhen inoculated with varying numbers ofviruliferous insects per plant, IRRI.

Evaluation of National Screening Nursery

(NSN) and international Rice Observa-

tional Nursery (IRON) trials for bacterial

blight (BB) and stem rot (SR) resistance

Each variety was planted in two 5-m-

long rows. Plants were inoculated withkresek at 20 d after transplanting (DT)

and with BB at 45 DT. Inoculation was

S. C. Ahuja, A. Singh, R. Pal, and U. by cutting 5 cm of the upper leaves with

Ahuja, Rice Research Station, Kaul a sickle dipped in inoculum prepared by

132021, India soaking small pieces of naturally infected

leaves in water for 20 min. Infection was

We evaluated NSN and IRON varieties for scored on a 1-9 scale.

BB, kresek, and SR resistance in kharif SR screening was done under natural

1980, 1981, and 1982. incidence, and evaluated at maturity on a

1-5 scale.

SR incidence was high only in 1982.

Resistant entries were selected and re-

tested. Entries with consistent reaction

to SR and BB for 2 yr or longer are give

in the table.

Sixteen NSN and 14 IRON entries

were consistently resistant. Resistant

IRON entries BR171-2B-8, IR13420-6-

BB intensity was high in most trials.

3-3-1, IR19660-131-3-3-3-3, IR9763-11-



14/28

daily. Experiments were conducted atroom temperature (25-30C).

Parentage distinctly influenced

nymphal development. Eight percent of

theNS nymphs emerged as adults in 13 dOnly 20% of the Bogor populationreached adulthood in 16 d. Development

of the hybrid F

reciprocal crosses was similar to that of

the Bogor population. When the F

NS as maternal parent was backcrossed

with the same population, nymphal

development was intermediate between

the NS and Bogor populations. However,

1 and F2 nymphs from

1 with

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,

IET8353, and IET4141) to SR, kresek,

and BB.

The International Rice Research News-

letter and the IRRI Reporter are mailed

free to qualified individuals and institu-

tions engaged in rice production and

training. For further information write:

IRRI, Communication and Publications

Dept., Division R, P. O. Box 933, Manila

Philippines.

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

Year Trial Test Severity index entriesEntries (no.) showing rating Total

1 2 3 4 5 7 9 (no.)

1980 NSN-I BB 6.6 HighNSN-II

1 26a 28 180 33 268

1981 NSN-I Kresek 6.9 High 32 12 72 49 157 321IRON BB 7.4 High 1 26 21 67 137 254

1982 NSN-I BB 5.4 Moderate 39 69 68 106 54 334Kresek 5.8 Moderate 6 206 104 11 327

IRON SR 4.0 High 4 23 79 71 158 _

330BB 7.0 High 3 35 38 93 133 343

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 (resistantto BB): BR161-2B-53, BR161-2B-58, BRl71-2B-8, IR134-20-6-3-3-1, IR19660-131-3-3-3, IR9763-11-2-2-3, 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 INSECTS

Inheritance of virulence of the North

Sumatra population of the brown

planthopper (BPH) on IR42

K. Sogawa and Djatnika Kilin, Indonesia-Japan Joint Programme on Food CropProtection, 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 popula-

tion. Nymphal development and adult

longevity and maturity of the NS pop-

ulation, 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 main-

tained 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


Table 1. Nymphal development of the NS and Bogor populations and their hybrid progenies on IR42

seedlings, Jakarta, Indonesia.

Crossa Nymphs Adult Developmental

tested emergence period of nymphsGrowth

which became adults indexbFemale Male (no.) (%)(d SD)

NS NS 20 80 12.9 1.3 B B 20 20

NS B15.5 0.6

20 301.3

B NS 20 14.5 2.1 0.7

14.3 1.5

10

2.1

(NS B) 2 20 30(B NS) 2 19

13.3 0.5 2.321

NS (NS B)12.8 1.0

201.6

55

B (B NS)

13.4 2.420 35 14.4 2.6 2.4

4.1

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

Table 2. Longevity and maturity of adultfemales of the NS and Bogor populations and

their hybrid progenies on IR42 seedlings,Jakarta, Indonesia.

Crossa Females Gravid Longevity

tested females (d S. D.)Female Male (no.) (%)

NS NS 20 90B B 21 5

NS B 20 5

B NS 17 18

(NS B)2 20 30

(B NS)2 20 10

NS (NS B) 20 50

B (B NS) 20 25

16.0 6.73.6 2.73.9 4.0

5.5 6.16.5 5.8

4.3 4.512.5 9.56.3 5.8

a See footnote, Table 1.

12 18 154 92 276


15/28

160

0160

103

334

99

02412

0

382

011

130

092940

222620

82238

9036

a Fifty first instar nymphs were used for each test. Number of adults emerged was recorded 22 daysafter introduction of the nymphs. b L = Leersia- BPH, R = rice - BPH.

on L. hexandra and Pelita I/1 were used, respectively.

Adult emergence of the Leersia- and rice-BPH, and their F

BF = brachypterous female, MM = macropterous male, BM = brachypterous male. dAdults emerged

c MF = macropterous female,

1 and F2 hybrids on rice and L. hexandra,Jakarta, Indonesia. a

Crossb No. of adults emerged

% adult

Host MF BF MM BM c emergence

L L

R R

L R

R L

(L R)2 d

(R L)2d

RiceLeersiaRice

Leersia

RiceLeersiaRice

LeersiaRice

Leersia

Rice

Leersia

0000

032

11

10

79

02129

0

723

064

Monitoring brown planthopper (BPH)

biotypes by rice garden in North Sumat

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 orvirulence is important in variety-oriented

BPH management. To monitor BPH

biotypes and forecast population surges

we designed a rice garden in which severa

rice varieties are planted separately in

5- 5-m plots in a randomized block

design.

1983 dry season, we used that technique

In Deli Serdang, North Sumatra, in

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 dis-

continuous classes: one that became

gravid and survived significantly longer

(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 F1and F2 progenies, 5-30% females became

gravid with 4-7 d average longevity. Back-

crossing the F 1 hybrid and the NS pop-

ulation increased the parentage of gravid

females, but backcrossing with the Bogor

population had no such effect (Table 2).

The results indicated that the NS pop-

ulations ability to infest IR42 is

inherited from recessive genes when inter

bred with avirulent BPH populations.

Possible genetic isolation between the

Leersia and rice brown planthopper

(BPH)

When a male and female from the Leersia-BPH within 4 min. Communica-

same population were tested, the male tion by acoustic courtship signals is not

moved to the female on the other seed- successful between the Leersia- and

K. Sogawa and Djatnika Kilin, Indonesia-Japan 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 NorthSumatra is morphologically indistinguish-

able from the rice BPHNilaparvata lugens,

but distinctive from each other by their

incompatible host requirements. To

determine possible genetic barriers, we

examined courtship reaction and cross-

ability of the populations.

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.

Courtship reactions were observed by

ling and they successfully mated. Homo-

gametic matings usually occurred within

4-5 min. Heterogametic matings between

theLeersia- and rice-BPH seldom

occurred except when the male and

female met by chance through random

wandering.

experiments were conducted using a simi-

lar 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 ofLeersia-

and 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

maleLeersia -BPH did not react. In

another test, a single male Leersia -BPH

was allowed to select between Leersia-

and rice-BPH females. The male always

moved to and mated with the female

To confirm our results, mating choice

rice-BPH.

cation,Leersia- and rice-BPH can mate

and produce viable hybrid progeny if

confined on the same plant. However,

the hybrid progenies were poorly adapte

to both host plants. Percentage of adult

emergence of the F1 BPH hybrids were8-26 on both hosts (see table). The F2

population also was viable, and survived

better than the F1 on the same host.

We conclude thatLeersia- and rice-BP

are noninterbreeding sympatric popula-

tions. Genetic interchanges between them

are greatly restricted by unsuccessful

courtship communication, incompatible

host plant preference, and breakdown of

host affinity in hybrid progenies.

Despite failure in courtship communi


( )


16/28

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 popu-

lation 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 dif-

ferences in BPH densities were recorded

among the rice varieties at six insect

development stages. Population was sig-

nificantly higher on IR42 and the sus-

ceptible 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

Insects/hill

VarietyResistance

gene F1 F1 B-female F2 F2(2 wk) S-nymph L-nymph (6 wk) S-nymph L-nymph

(4 wk) (5 wk) (7-8 wk) (8-9 wk)

Pelita I/1 None

IR42

2.4 ab 252 a

bph 2

67 a

3.3 a 202 a

4.3 a 60 a 6.0 a

IR36 70 abph 2 1.5 bc 81 b 4.3 a 83 a 7.3 a

IR2620 b 0.9 ab 27 b 1.7 b

Bph 1 1.1 bc 16 bcIR56

7 b 0.4 b 7 bc 0.1 bBph 3

IR461.3 bc 20 bc 5 b 0.2 b 0.2 c 0.2 b

Bph 1 1.0 bc 3 c 4 b 0.1 b 0.3 c 0.2 bBahbolon Bph 3 0.4 c 1 c 1 b 0.02 b 0.1 c 0.1 b

a Values followed by the same letter are not significantly different at 5% level. F 1 = first generation,F2 = second generation, M-female = macropterous adult female, B-female = brachypterous adult

theses indicates weeks after transplanting.female, S-nymph = 1st- to 3d-instar nymphs, L-nymph = 4th- to 5th-instar nymphs. Time in paren-

IR26, which had been attacked by BPH collected BPH. The rice garden method

biotype 2, showed good resistance. is recommended as a simple but highly

Results indicated that the local BPH practical method of monitoring BPH

population was biotype 3, adapted to biotype shifts, and forecasting BPH

IR42, which corresponded with population surge and development of

laboratory identification of locally other insect pests and diseases.

Relationship between biochemical

characteristics of rice and establishment

of yellow stem borer (YSB) larvae

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

641003, India

We conducted screenhouse experimentsto determine the ability of YSB larvae to

establish themselves on rice accessions

with selected biochemical characteristics.

accessions (see table) and the susceptible

check Jaya were transplanted 1 /hill in 10-

cm 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.

Twenty-day-old seedlings of 6

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 ofaccessions were analyzed for total N,

crude silica, lignin, and cellulose.

Larval establishment was lowest in

W1263, followed by Co 18 and IR13641-

4 (see table). It was highest in susceptible

Jaya. Only crude silica content was sig-

nificantly related to percent larval estab-

lishment. The resistant accessions had

more silica than other accessions in their

stems.

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

Accession

W1263Co 18IR13641-4

SornavazhaiJaya

IR13639-39

Larvalestablishment

(%)

92023

454550

Leaf sheath

Total N Crude

(%) silica(%)

3.6 4.82.4 2.35.0 0.64.9 1.43.1 3.73.1 1.7

Stem

Crude Lignin Cellulose

silica (mg/g) (mg/g)

(%)

11.40 417 6719.87 532 608

12.12 279 7375.85 143 8873.17 583 5666.51 464 710


Inhibitory effects of insecticides on

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 andB. 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 andB. bassiana spores.

media before planting, or was surface-

applied on hardened media. All insecti-

cides significantly reduced spore germi-

nation of both fungi (see table). M.

anisopliae was more sensitive to insecti-

Insecticide was mixed into the culture

M-female


17/28

Effect of insecticides on M. anisopliae and B. bassiana spore germination, IRRI, 1983.

Spore germinationa (%)

Insecticide Insecticide mixed with mediab Insecticide on media surfacec

M. anisopliae B. bassiana M. anisoplia B. bassiana

MonocrotophosBPMC

CarbosulfanAzinphos ethyl + BPMC

No insecticide

Insecticide mean

Azinphos ethylDeltamethrin

Methyl parathionMIPC No insecticide

Insecticide mean

0 cl b

0 c0 c

99 a

0

20 d56 c

66 b99 a

36

0 e

Recommended for BPH controld

2 c 36 d0 d 66 c0 d 28 e

32 b 72 b

100 a 99 a

9 51

Causing BPH resurgencee

71 c 16 d90 b 81 b

6 e 15 d38 d 75 c

100 a 99 a

51 47

95 b36 d

68 c

68 c

100 a

67

77 c

89 b72 d

67 e

100 a

77

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

media at 40-45C, then plated. Fungal spore suspension (0.3 ml/petri dish) was spread on the cooled300 random spores counted 24 h after insecticide application. bInsecticide mixed with the culture

and hardened media. cInsecticides and fungi spores were mixed together in suspension and 0.3 ml/

0.75 kg ai/ha. eAt the minimal rate that causes resurgence (0.50 kg ai/ha, except deltamethrin at petri dish was spread on top of the hardened culture media. dAt the national recommended rate of

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 incidencein 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 sub-

plots) were tested in a split-plot design

with 3 replications. TKM9 was planted in

1 6-m2 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

TreatmentGLH/10 BPH/10 WM GM

hillsYield

hills (% damaged leaves) (% silvershoots) (t/ha)

Water managementContinuous flooding 19 b 9 b 7 bAlternate flooding

2a13 a

5.6 a4a 4a 3 b 4.9 b

Spacing15 10 cm 13 a 6 5

18 b20 10 cm5.0

6 618 b30 10 cm 6 5 3 5.5

5.2

and draining

32

N level

50 kg/ha100 kg/ha150 kg/ha

15 a 3a 516 a 7 b 518 b 8 c 5

2 4.8 b2 5.2 b3 5.7 a

K level42 kg/ha 17 683 kg/ha

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

516

26 5 3

5.25.3

cides. Recommended insecticides reduced

spore germination more than resurgence-

causing insecticides did, probably becaus

a higher dosage of the recommended in-

secticide 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 spor

germination. Only methyl parathion, the

second most powerful BPH resurgence-

causing insecticide, greatly reduced spore

germination.

Individuals, organizations, and media are

invited to quote or reprint articles or

excerpts from articles in the IRRN.

plot were counted 20, 45, and 70 DT.

Grain yield was recorded.

Alternate flooding and draining signi-

ficantly reduced GLH and BPH popula-

tions 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 gallmidge (GM) incidence in plots with inter-

mittent 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



18/28

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 rearingtubes at 29C 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 per-

centage 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 un -

treated (see table). The varying rate of

parasite emergence in the insecticide

treatments and the untreated set was

caused by the difference in field parasiti-

zation rate rather than by the insecticides.

Insecticide action on developing parasites

Insect pests of rice in the Sikkim Hills

N. S. Azad Thakur, Indian Council ofAgricultural Research Complex for NEH

Region, Shillong 793013, India

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. BrownplanthopperNilaparvata lugens (St1) and

whitebacked planthopper (WBPH) Soga-

tella furcifera (Horv.) were generally

minor pests, but in 1978 WBPH infesta-

tion was high. Gall midge, caseworm,

grasshopper, rice bugs, rice hispa, rice

leafhoppers, semilooper, spittle bug, leaf

beetles, and rice skipper were of minor

importance.


Percent emergence of larvae and parasite adults from insecticide-treated and untreated host eggs a

Bhubaneswar, India, Feb 1982.

Emergence (%)

ConcentrationInsecticide

(ai %) Larvae Adults

Chlorpyriphos 0.025

0.0500.075Fenitrothion 0.025

0.0500.075

Fenthion 0.0250.0500.075

Formothion 0.0250.0500.075

Phenthoate 0.0250.0500.075

Phosphamidon 0.0250.0500.075

Quinalphos 0.0250.050

Eggs Eggs Eggs

(treated)

Eggs(untreated) (treated) (untreated

32.7 50.0 10.3 32.6

56.0 57.1 6.0 12.222.2 85.7 50.0 46.824.5 2.4 11.6 20.043.8 48.5 30.1 81.333.5 35.7 41.1 60.022.6 59.1 45.4 12.067.6 76.9 70.9 65.049.8 59.0 66.7 82.443.6 78.6 60.2 63.624.4 52.8 36.0 20.022.3 74.1 51.5 54.777.5 53.6 47.1 66.728.0 26.8 26.0 30.033.1 91.0 73.4 66.716.4 11.1 17.2 28.649.5 60.0 63.6 12.053.6 43.3 43.5 60.0

19.2 39.3 25.0 77.532.7 44.8 41.3 38.5

0.075 82.1 97.7 47.6 58.5

LSD 5% Insecticide 2.6

InteractionUntreated vs treated 0.8

3.6

2.30.73.2

and host eggs was adequately circum- the egg mass. The chorion of the egg may

vented by the hairy matrix surrounding also have limited insecticide penetration.

Rice insects in the Sikkim hills.

Common name

Striped stem borerTussock caterpillarPink stem borerRice swarming

caterpillarCommon cutwormEar-cutting caterpillarSemilooperRice skipper

Yellow stem borer

Leaffolder

Rice casewormRice bugStink bug

Spittle bugBrown planthopperWhitebacked

Leaf rolling weevilsplanthopper

Root weevilRice gall midgeGreen leafhopperZigzag leafhopperAphidSmall grasshopper

Scientific name Family Order % infestation

Chilo suppressalis (Walk.) PyralidaeLepidoptera 7.2 to 19.5

Euproctis varians (Walk.) Lymantridae LepidopteraSesamia inferens (Walk.) Noctuidae Lepidoptera 7.2 to 19.5

Spodoptera mauritia (Boisd.) Noctuidae Lepidoptera

S. litura (F.) NoctuidaeMythimna separata (Walk.) NoctuidaeMocis [=Remigia] frugalis (Fabr.) Noctuidae Parnara guttata HesperidaeBremer & GreyScirpophaga [=Tryporyza] Pyralidae

Cnaphalocrocis medinalis Pyralidae

Nymphula depunctalis (Guen.) Pyralidae

Leptocorisa sp. Alydidae

Cletus sp. Coreidae

Cosmoscarta sp. CercopidaeNilaparvata lugens (Stl) Delphacidae

Sogatella furcifera (Horv.) Delphacidae

incertulas (Walk.)

(Guen.)

LepidopteraLepidopteraLepidopteraLepidoptera

Lepidoptera

Lepidoptera

LepidopteraHemipteraHemipteraHemipteraHemipteraHemiptera

7.2 to 19.5

12 to 15

Centrocorynus scutellaris Attellabidae Coleoptera

C. rufulus Voss. Attellabidae Coleoptera

Phytoscaphus triangularis (Oliv.) Curculionidae Coleoptera

Orseolia oryzae (Wood-Mason) Cecidomyiidae Diptera

Nephotettix nigropictus (Stal) Cicadellidae Homoptera

Recilia dorsalis (Motsch.) Cicadellidae Homoptera

Rhopalosiphum padi (Linnaeus) Aphididae Homoptera

Oxya chinensis (Thunberg) Acrididae Orthopter 5 to 8

(Gyll)


19/28

Tabanus (Diptera: Tabanidae) eggs, an

alternative host of rice stem borer (SB)

egg parasite Telenomus dignus (Hymenop-

tera: Scelionidae)

A. T. Barrion and J. A. Litsinger, IRRI

Telenomus spp. are common egg parasitesofScirpophaga 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,

in 14 Philippine provinces. Telenomus

dignus Gahan emerged from 85% of 94

HF egg masses. Eggs collected (6,751) and

parasitization percentage (87) were high-

est 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. Al-

though HF eggs are longer and moreslender 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.

Incidence of parasitization by T. dignus on eggs of Tabanus spp. collected from 14 rice, maize, and

coconut provinces in the Philippines, 1978-84.

Parasitizationa

on Tabanus spp. eggs

Province,

municipalitySampling date Rice Maize Coconut

Eggs Parasitization Eggs Parasitization Eggs Parasitization

(no.) (%) (no.) (%) (no.) (%)

Cagayan

Mt. Province

La Union

Solana 23 Sep 1981 510 51 130 84

Banawe 27 Mar 1979 115 75

Agoo 13 Oct 1982 106 67 520 65San Fernando 14 Oct 1982 530 85

Bani 12 Oct 1982 120 78 260 81

Manaoag 31 Jan 1979 38278 284 87

Los Baos 3 Mar 1979 84 38 120 85 22 Feb 1982 356 33

30 Jan 1984 142 91 650 43 15 Feb 1984 108 87 108 78

Santa Rosa 16 Mar 1980 115 40

Malvar 7 Mar 1979 240 60 390 95

Tanauan 20 Aug 1980 98 50 340 64 650 17

Aborlan 24 Apr 1979 76 54 82 100

Tigbauan 17 Jan 1978 310 78 285 44 130021 Oct 1982 284

96

66 530 88

Oton 17 Jan 1978 81 42

324 100

Pangasinan

Laguna

Liliw 14 Sep 1979 910 78

Batangas

7 Mar 1979 360 94 110 88

Palawan

Iloilo

10 NOV 1978

Capiz

Agusan Del Sur

Bukidnon

Zamboanga Del Sur

North Cotabato

South Cotabato

Dumarao 17 Feb 1981 4 86 81

Del Monte 26 Jul l981 162 74

Pangantukan 10 Jul 1979 212 47

Molave 4 Aug 1981 320 50

Kabacan 20 Mar 1980 484 100

Koronadal 24 Feb 1983 361 88 92 82 487 85

Total 3190 66 3673 72 6751 87

a Dash = 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 sus-

pended on foam sheets with their roots

in the water. Three groups of aquatic

invertebrates fed on rice rootslarvae

(see figure) of seven species of chirono-

mid midges dominated by Chironomus

kiiensis Tokunaga, nymphs and adults o

a corixid water boatman Micronecta

quadristrigata Breddin, and adult ostraco

crustacean Cypris sp.

We evaluated damage at 0, 20, 40, 10

and 500 arthropods per seedling for 72 h

The corixid cut more root hairs, but

damage did not increase beyond 20adults/seedling. Chironomid and ostraco

damage increased progressively with high

er densities. Chironomid larvae damaged

roots more than ostracods at equal densi

ties. In the field, dapog-raised seedlings

are particularly vulnerable to root damag

because before transplanting, they grow

for 2 wk on banana leaves without soil

Injury to rice seedling roots caused by chiro-nomid midge larvae (arrow).



20/28

Pathogenicity of Beauveria bassiana on

brown planthopper (BPH), whitebacked

planthopper (WBPH), and green leafhop-

per (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 planthop-

pers 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 300-litre 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 micro-

scope examination for infection.

Isolates E, RS149, and 101481-5 were

the most virulent against all insect species

(Table 1). RS149 and 101481-5 had high-

er virulence to BPH than to GLH and

WBPH. BPH was most susceptible toB.

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 viru-

lence. 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 Agri-cultural University Rice Research Station,

Kaul 132021, Kurukshetra, Haryana,

India

Before 1982 LF Cnaphalocrocis medinalis

Guene (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, andWBPH in the laboratory, IRRI, 1983.

Infectionb (%)Isolate (I)a

BPH GLH WBPH I-means

RS149RS413

RS252102081-2

101481-5102381-8CEUntreated

T-means

53 a (a)

36 abc (a)

30 bc (a)31 abc (a)

49 ab (a)33 abc (a)50 ab (a)

35 (a)

0 d

34 a (b)35 a (a)29 a (a)28 a (a)29 a (b)29 a (ab)41 a (ab)

0 b

28 (b)

16 a (c)16 a (b)29 a (a)18 a (a)23 a (b)18 a (b)26 a (b)

18 (b)

0 b

34 ab29 b29 b

25 b

33 ab26 b39 a

0 c

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.

Infectionb (%)

Isolate (I)a

BPH GLH WBPH I-means

GLH-1GLH-3

GLH-4GLH-5GLH-6GLH-8

GLH-9GLH-11GLH-16

GLH-22

GLH- 19

GLH-20102081-2102381-8CUntreated

T-means

14 c (a)30 abc (a)

25 abc (ab)20 bc (a)25 abc (a)43 ab (a)34 abc (a)

24 abc (a)39 abc (a)

24 abc (a)

31 abc (a)51 a29 abc (a)

46 ab (a)0 d

29 (a)

14 c (a)14 c (a)40 ab (a)28 abc (a)13 c (a)20 bc (a)19 c (a)18 bc (a)18 c (b)11 c (a)16 c (a)11 c (b)24 bc (a)53 a (a)

21 (ab)

0 d

24 a (ab)15 a (a)

11a (b)24 a (a)23 a (a)33 a (a)26 a (a)16 a (a)25 a (ab)18 a (a)25 a (a)25 a (b)19 a (a)29 a (a)

20 (ab)

0 b

17 c20 bc25 bc24 bc20 bc32 ab26 bc

19 bc27 bc

18 c24 bc

29 abc24 bc43 a

0 d

23

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

than to GLH and WBPH, and isolate that B. bassiana strains have potential as

GLH-4 was more virulent to GLH and microbial agents to control BPH, GLH,

BPH than to WBPH. The results suggest and WBPH.

infestation. In 1983 kharif, infestation

caused 60-70% leaf damage. Infestation caterpillar, and its parasites

began the first week of Aug and con-

by heavy rainfall in late Jul (197.9 mm) Coordinated Rice Improvement Project,

and Aug (264.l mm). An average 20% V. C. Farm, Mandya, Karnataka, India

damage was observed in Ambala, 27% in

Karnal, 29% in Sirsa, and 31% in Kuruk-

shetra. Populations were higher on the In 1983 wet season, Cryptoblabes

late transplanted crop. There were no dif- gnidiella (Millire) were feeding and

ferences in damage between scented and breeding on azolla in and around the

unscented varieties. Mandya Rice Research Station. The sem

Cryptoblabes gnidiella, a fern-feeding

tinued to mid-Oct, probably encouraged Gubbaiah, rice entomologist, All-India


21/28

N. Chandramohan and S. Chelliah, Tamil

Nadu Agricultural University (TNAU),

Coimbatore 641003, India

We studied the parasite complex of YSB

Scirpophaga incertulas (Walk.) fromMay 1980 to Jun 1982 at TNAU

Coimbatore.

Four egg and four larval parasites were

observed (see table). Egg parasitization

was greater (47%) than larval parasitiza-

tion (10%).

Tetrastichus schoenobii (Ferriere) was

the predominant egg parasite. It peaked

with 47% parasitism in Dec-Jan.

Apanteles schoenobii (Wilk) was the pre-

dominant larval parasite.

Parasite complex of yellow stem borer

(YSB)

Arifin Kartohardjono, Agency for Agri-

cultural Research and Development,

Bogor Research Institute for Food Crops,P. O. Box 368, Bogor, Indonesia

WBPH Sogatella furcifera Horvath is aserious 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 pre-

dators were counted. At early growth

stages, WBPH population was low and

less than the spider population. WBPH

population peaked 62 d after transplant-

ing, then decreased. The spider popula-

tion followed a similar trend (see figure).

Wet season population fluctuation of

whitebacked planthopper (WBPH) in

West Java

Parasitization of azolla caterpillar, Mandya,India.

Parasitization (%)Sep1983 Apanteles B. Xanthopimpla

sp. excarinata sp.

Wk 1 30 8 1Wk 2 35 9 1Wk3 43 11 0

Wk4 50 14 4

Mean 40 10 1

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 byApantales 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 killedthe azolla.

Egg and larval YSB parasites at TNAU Coimbatore, India.

Number of WBPH and spiders at different agesof Cisadane rice in 1983-84 wet season.Karawang, West lava, Indonesia.

Parasite

Tetrastichus schoenobiiFerriere

Telenomus rowani GahanTelenomus sp.Scelio sp.

Exoryza schoenobiiWilkinson

Rhaconotus sp.Amauromorpha

accepta methathoracica

Family

Eulophidae

ScelionidaeScelionidaeScelionidaeBraconidae

BraconidaeIchneumonidae

Hoststage

affected

Egg

Egg

EggEggLarva

LarvaLarva

Meanparasitism

(%)

47

611

10

31

Month oactivity

Dec-Jan

OctJan-FebJan-FebJan-Feb

Jan-Feb

Sep

Pest control and managementWEEDS

Effect of time of herbicide application

on rices of different durations

A. M. Ali, Indian Council of Agricultural

Research (P. L. 480) All India Cooper-

ative Rice Improvement Project on WeedControl, Tamil Nadu AgriculturalUniversity (TNAU), Coimbatore 641003,India

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), medium

duration 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-


international rice research newsletter vol.9 no.6

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