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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.
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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.
6 IRRN 9:6 (December 1984)
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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 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
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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.
GENETIC EVALUATION AND UTILIZATION
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,
8 IRRN 9:6 (December 1984)
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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-
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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
10 IRRN 9:6 (December 1984)
grain
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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
IRRN 9:6 (December 1984) 1
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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.
12 IRRN 9:6 (December 1984)
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-
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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-
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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
14 IRRN 9:6 (December 1984)
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
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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
IRRN 9:6 (December 1984) 1
( )
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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
16 IRRN 9:6 (December 1984)
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
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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
IRRN 9:6 (December 1984) 17
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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.
18 IRRN 9:6 (December 1984)
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)
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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).
IRRN 9:6 (December 1984) 1
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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%
20 IRRN 9:6 (December 1984)
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
-
8/4/2019 International Rice Research Newsletter Vol.9 No.6
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-
IRRN 9:6 (December 1984) 21