Rice stem borer is also commonly known as the paddy stem borer
and yellow borer of rice.
It is distributed in all Asian countries.
It is a regular pest in all parts of India and in all districts
of Andhra Pradesh.
Seasonal occurence It occurs both in kharif and rabi seasons
in Andhra Pradesh.
The pest affects the crop in the nursery, soon after transplanting
and also in the pre-earhead stage.
In case of late inter seasonal and the early second crops, the
damage is done to the young transplants where in the case of late
first crop and early inter seasonal crops, more damage is done
at the earing stage.
Life history
The female moth is bigger than the male and its forewings are bright
yellowish brown with a distinct black spot in the center.
The abdomen is wide, the tip being covered with tufts of yellowish
hairs.
The male moth is pale yellow - the abdomen is slender and the anal
end has a thin hairy covering dorsally.
Spots on the forewings are not conspicuous.
The female moth lay eggs near the top of the leaf blade early at night
in small masses covered with hairs and scales derived from the anal
tuff.
The ovi - position occurs upto 5 nights from emergence. The moths
are short-lived and die 2 to 3 days after ovi - position.
The fecundity of the moth vary from 100 to 150 eggs. The eggs are
creamy white, flattened, oval and scale like. Egg period is 5 to 8 days.
The first instar larvae are about 1.5 mm long and 0.5 mm wide. Pale
yellow in colour with dark brown prothoraxic shield and orange head.
Larvae crawl upward towards the tip of the plant – during roming
period many larvae die.
Remaining larvae descend towards the base of the plant and crawl between
leaf sheath and stem.
They enter into leaf sheath and feed on tissue for about a week and
bore into stem through nodal region.
In mature rice plants the catter pillars bore into the stalk region
just below the ear head.
Larval period lasts for 30 days.
Pupation takes place inside the stem mostly in the lowest node of
the plant, and just above water level
In seedling stage, pupation take place in the root region .
In single cropped areas mature larvae diapause in rice stubbles after
harvest in December.
Larvae pupate and emerge as moths after the monsoon rains.
Ecology
Egg development takes place at about 160C with an optimum
temperature of 24 to 290C and relative humidity of 90 to
100 percent.
Hatching is drastically reduced at low temperatures of 130C
and relative humidity of 70 per cent.
The rate of larval development is positively correlated to temperature
range from 17 to 350C.
The threshold for pupal development is 15 to 160C.
Nature and symptom of damage
Vegetative stage
Larvae feed on green tissue of leaf sheath for 2 to 3 days.
Bore into the stem at the nodal position and feed on inner tissue
of plant – Under Severe conditions, it bores at the base and move
upwards – Central leaf whorl does not unfold, turns brown –
dries off.
Lower leaves remain green.
Heading stage
Larvae bore at the peduncle node.
White heads are the resultant effect.
Damage is maximum at this stage.
Yield loss
Early planted crop 1-19%
Late planted crop 38-80%
Control measures
Cultural Methods
Since the eggs are laid near the tip of the leaf blade, clipping the
seedlings before transplanting reduces the carry-over of eggs from seed
bed to the transplanted field.
Harvesting at ground level or ploughing after harvesting remove majority
of larvae and pupae.
Mechanical Methods
The use of light traps was recommended earlier but now this method
is not advocated as many beneficial insects are also attracted and killed.
Use Of Pheromone traps Now a days the sex pheromones are utilized
for mass trapping of male moths.
Biological Methods
Telenomus spp, Tetrastichus spp and Trichogramma Spp are identified
as dominant complex stem borer egg parasitoids, they could not
be utilized in a big way because of the limitations in mass rearing
and releasing in our conditions.
When these parasites are found in abundance the use of insecticides
can be postphoned.
Resistant Varieties : Sasyasree ( RNR 446 ), Rathna and Kaveri were
observed tolerant to this pest in Andhra Pradesh.
Chemical Methods
Several chemicals were reported effective for control of stem borer,
chemical control may be practiced without relying on only one chemical
considering the cost, availability and safety to natural enemies.
ETL recommended– 5% dead hearts or 1% white ear or one egg mass
or one adult /Sq.mt. (Recommendation based on growth of the crop) Nursery.
Carbofuran 3G @ 42 Kg/ha or Phorate 10 G @ 12.5Kg /ha to be applied
7 days after germination of seed or spraying of Monocrotophos 1.6 ml
or Chlorpyriphos 2.5 ml/li or Quinalphos 2ml/li at 10 days interval
starting from 7 th day after germination.
Main Field
Transplanting to panicle initiation
Carbofuran 3 G @ 25 Kg/ ha OR Spraying of Monocrotophos 1.6 ml,
or Chlorpyriphos 2.5 ml OR Quinalphos 2.5 ml or Carbaryl 3 gms or
Phosphomidon 1 ml/ lit water.
Panicle initiation to booting:
ETL: 1 moth / Sq.mt. Carbofuran 3 g @ 25 Kg / ha OR Spraying
of Monocrotophos 1.6 ml or Chlorpyriphos 2.5 ml OR Quinalphos 2.5
ml or carbaryl 3 gms or Phosphomidon 1 ml/ lit. of Water.
Post flowering
Spray Monocrotophos 1.6 ml or carbaryl 3 gms. OR Phosphomidon 1 ml
or Cartap hydrochloride at 2 ml/ lit of water to be sprayed OR Cartap
hydrochloride 4 G granules @ 20 Kg / ha to be applied.
The rice leaf folder, earlier considered as a minor and sporadic
pest of rice in many Asian countries, appears to have become increasingly
important with the spread of high yielding rice varieties and
accompanying changes in cultural practices.
It is distributed in many rice growing countries like India,
Pakistan, Bangladesh, China, Burma, Bhutan, Indonesia, Japan,
Nepal, Malaysia, Kerala, Vietnam, Srilanka, Taiwan, Thailand,
Afghanistan and Australia etc.
In India it is a serious pest in Andhra Pradesh, Madhya Pradesh,
Orissa & Tamilnadu.
In Andhra Pradesh it is distributed as a major pest in all rice growing
districts particularly Krishna-Godavari delta, Khammam, Nagarjuna sagar
project area.
All rice growing districts of Telangana are more proned to the damage
of this pest.
Nellore district is also experiencing more out breaks.
Seasonal Occurance
The pest is reported throughout the year although they are most abundant
during wet season.
Infestation usually occurs during late growth stages of the crop.
Life History
Each female moth may lay about 300 eggs during its life time
in singles are rows parallel to mid rid of both sides of young
leaves.
Incubation period varies from 3-6 days.
Hatched larvae are white translucent in colour with light brown
head initially - later body of larvae turn green.
Larvae crawls to the base and feed on young unopened leaves.
Second instar larvae migrate to older leaf and folds the leaf.
Five larval instars are reported.
Full grown larvae is 16 mm long and yellowish green in color with
a dark brown head and prothoraxic shield.
Mature larvae jump or wriggle rapidly – Larval period is 15 –
20 days.
Pupation takes place inside leaf folder and pupae are slender and
brown in color – pupal period is 6-8 days.
Adult moth - yellow brown in colour – 10-12 mm long.
Fore wings have three dark oblique lines and hind wings have a broad
anal area.
Female attracts its male with a pheromone.
Adults live about for a week and hide on host plant during day time.
Ecology
High humidity and optimum temperatures are conducive factors for the
rapid multiplication of the pest.
The larval period is significantly prolonged when the larvae are reared
on leaves of rice plants at the ripening stage.
Nature and Symptoms of Damage:
The larvae fold the leaves and scrape the green tissues of the leaves
from within and cause scorching and leaf drying.
Each larva destroy several leaves by feeding.
In severe infestations, each rice plant may have several rolled leaves
which restrict’s photosynthetic activity.
At 17 to 26.% of leaf damage the loss in yield vary from 16 to 21%.
Control Measures Cultural
Avoid close planting and application of more nitrogenous fertilizers,
as close
crop growth and heavy manuring are conducive for leaf folder activity.
Sufficient quantities of Potassic fertilizers are to be applied to
reduce infestation.
Grow varieties with high silica content.
Mechanical
Pass a thorny brush or a rope across the crop in vegetative phase
to unfold the leaves and to expose the larvae to insecticidal application.
Biological
Trichogramma japanicum and Copidosomopsis nacoleidae were recorded
as important egg parasitoids.
Trichomma cnaphalocrosis as larval parasite and Xanthopimpla flavolineata
and Tetrastichus ayyari as pupal parasites were reported to suppress
the pest.
Chemical Control
Spraying of Monocrotophos, 1.6ml, Chlorpyriphos 2.5ml or Quinalphos
2.5ml or Acephate 1gm or Carbaryl 3gm or Cartap hydrochloride
2gm/lit of water to be sprayed two times at 10days interval or
apply cartap hydrochloride 4G. 10kg /acre.
Since larvae feed by hiding in leaf folds the insecticide do not
contact larvae.
So care has to be taken to unfold the damaged leaves before spraying
for effective control.
Economic threshold level (ETL)
One damaged leaf/hill during planting to pre-tillering period 1 to
2 freshly damaged leaves/hill during mid-tillering to booting period.
Gundhi bugs are also called stink bugs as a characteristic foul
odour is produced by scent glands present on the abdomen.
These stink bugs are distributed in all the tropical and sub-tropical
regions.
In India and in all rice growing areas and in Andhra Pradesh.
Its occurrence was observed in all the districts.
In Telangana district and in Chittoor district its out breaks were
recorded in recent years.
Seasonal occurence
The population build up is usually noticed at the end of rainy season
and declines rapidly during dry months when temperatures are unfavorable.
The maximum population is usually observed during September to November
months.
Life History
The adult bug is long and slender and measures about 16-19 mm long.
Diurnal in habit but active during early morning and evening.
Bugs fly short distances – Females are stronger fliers.
Female lay 250-300 eggs in two or three straight rows along side mid
rib on upper surface of leaf blade
Eggs are disc shaped, dorsally flat and elliptical.
Incubation period is one week
Bugs complete 1 or 2 generations on grasses and then migrate to rice
fields.
Newly hatched nymphs are green but turn brown as they grow.
Nymphs feed gregariously until the fourth instar.
Nymphal period varies from 25-30 days with 5 instars.
Ecology
All the stages of the pest are vulnerable to changes in temperature
and humidity.
Favourable conditions: Temperature 27 –28° C Relative Humidity
80-82%
Flowering stage warm and cloudy weather and frequent drizzles favour
population build up.
Heavy rains reduce population.
Extensive weedy areas near rice fields and staggered rice planting
favour high population.
Nature and symptoms of damage
Both nymphs and adults suck sap from the grain at the milk stage.
Damage by nymphs is more compared to adults.
Unfilled or partially filled grains with a black patch on effected
grain.
Average incidence – 5 to 10 %, Severe - 40-60 %.
Control Measures Cultural control
Removal of weeds in the vicinity of paddy crop as the pest breeds
on a variety of grasses prior to its migration to rice crop.
Mechanical control
Collection of the bugs by hand netting is suggested. Sweeping of rice
plants with winnows smeared with sticky material like castor oil.
Chemical control
Spraying of Monocrotophos 1.6 ml or Endosulfan 2 ml per litre of water
once at flowering and another at grain hardening stage or dusting of
Endosulfan 4 % or Carbaryl 5 % @ 25 kg/ha in evening hours.
If needed application has to be repeated after 10 days.
The leaf hopper gained economic significance as regular pests
of rice. The leaf hoppers attack all the aerial parts of rice
plant. This pest is distributed in Bangladesh, Burma, Hongkong,
Indonesia, Malaysia, Pakistan, Philippines, Taiwan and India.
In India it is severe in Andhra Pradesh, Madhya Pradesh, Orissa
and moderate to low in other rice growing states. In Andhra Pradesh
it is found in all the districts where rice is grown.
Seasonal Occurence
Leaf hoppers move from one rice crop to another rice crop and during
intervening periods they feed and breed on grasses found in rice ecosystem.
The hoppers remain active the year round.
In general two population peaks can be observed one in first crop
season and the other in second crop season.
The insects are usually more abundant during dry season than during
wet season.
Life History
The adult is a stout, pale red to brown coloured moth which measures
20 mm long with a wing expansion of 40mm.
Moths feed on nectar from flowers and honey dew secreted by Homopterian
insects.
The female moths start egg laying in three days in batches of 100
between leaf sheath and stem.
Newly laid eggs are spherical, greenish white, later turns to pale
yellow and finally black before hatching. The egg period varies from
5 to 7 days.
Hatched caterpillars are dull white, and later turn to green with
the orange or brown head.
Four longitudinal light grey to black stripes run along the body.
The larvae are nocturnal in habit they hide in loose soil, under trash,
in stubbles, in leaf sheaths and in whorls.
During night, they become active and feed on foliage.
The larval period lasts for about 28 days with 5 to 6 instars.
Pupation takes place in the soil.
Sometimes naked pupae are also observed among the tillers.
The pupal period is 8 – 11 days.
Ecology
The abundance of Green hoppers has been correlated to high temperature,
low rainfall and abundant sunshine.
The rate of nymphal development is faster at high temperatures. (14.1
days at 35° C and 37.3 days at 20° C).
The rapid build up of pest population was observed at tillering and
panicle initiation stages of rice crop.
The insect can withstand long periods of starvation. They are highly
attracted to light at nights.
Nature and symptoms of Damage
The nymphs and adults cause direct damage to rice crop by sucking
sap from leaf sheaths and blades.
The feeding marks predispose plants to fungal and bacterial
infections.
The affected leaves and plants turn to yellow colour and growth
is retarded.
They indirectly acts as vectors by transmitting virus diseases
such as Tungro and Yellow dwarf.
They also feed on some grasses like Cynodon dactylon, Echinochloa
crussgalli and Eleusine indica, etc.,
Control Measures - Cultural Methods:
Avoid excess application of nitrogenous fertilizer.
Maintain weed free field bunds.
Biological Methods
A number of predators like Lycose Pseudoannwlata on nymphs and adults,
Cyrtorlinus lividipennis on eggs and nymphs and parasites like Tomosvaryella
spp and Pepunculus spp on nymphs and adults were reported as important
against green leaf hopper.
But their rearing and practical application is not practiced.
Minimum insecticidal use was suggested when these natural enemies
are in good numbers in rice fields.
Chemical Control
Since green hoppers are vectors of virus diseases, use of insecticides
having immediate knock down effects are preferred.
Soil application of Carbofuran granules into the root zone at the
time of planting or few days after planting helps in controlling Tungro
virus by preventing feeding of Jassid vectors.
Seedling root dip in 0.02 @ Chlorpypiphos solution for overnight (12
hours) was recommended not only for this pest but also to other rice
pests.
In case of time shortage addition of 1 % urea to insecticide emulsion
is suggested in which case root dip time can be reduced to 3 hours.
Nursery
Carbofuran 3 G @ 42 kg/ha or Phorate 10 G @ 12.5 kg/ha to be applied
7 days after germination of seed. Or
Spraying of Monocrotophos @ 1.6 ml or Chlorpyriphos 2 ml or Quinolphos
2.5 ml per litre of water, at 10 days interval starting from 7 th day
of germination.
Main field:
Soil application of Carbofuran 3 G @ 25 kg/ha in the last puddling
or at 10 days after transplanting keeping 1-2" of water level.
Or
Foliar application of Monocrotophos 2 ml or Chlorpyriphos 3 ml per
litre of water at 10 day interval starting 10 days after planting.
If population is more for immediate knock down affect combination
of Monocrotophos 2.0 ml with dichlorophos 1 ml/litre of water is recommended.
Ethofenprox 10 EC at 1.5 ml or BPMC 50 EC at 2 ml/lit also are recommended
at foliar sprays.
Planting to Pre-Tillering,
Mid-Tillering & Panicle Initiation & Booting
Foliar application of Carbaryl, Phosalone, Phosphomidon
@ 0.5 kg a.i./ha or Cartap WP @ 300 g a.i./ha. Ethofenprox EC
@ 75 g a.i./ha or Granular application of Carbofuron @ 0.75 kg a.i./ha
or Phorate @ 1.25 kg a.i./ha or Fipronil @ 0.75 g a.i./ha.
Planting
to Pre-Tillering
Spray Monocrotophos,
Carbaryl, Phosalone, Phosphomidon @ 0.5 kg a.i./ha or Cartap WP @
300 g a.i./ha, Ethofenprox EC @ 75 g a.i./ha or apply Carbofuran granules
@ 0.75 kg a.i./ha or phorate granules @ 1.25 kg a.i./ha or Fipronil
granules @ 0.75 g a.i./ha.
Mid-Tillering
As recommended
above.
Panicle
Initiation to Booting
As recommended
above.
Economic threshold level(ETL)
Planting to Pre-Tillering
2 insects/hill in Tungro endemic area.
10 insects/hill in other areas.
The brown plant hoppers are one of the most serious pests of
paddy having become increasingly important in recent years.
They are distributed throughout South and South Asia in the
early 1970s.
In India the pest was reported as a major one in states of Kerala,
Karnataka.
Tamilnadu, West Bengal and Andhra Pradesh.
Outbreaks have coincided with large scale release and cultivation
of high yielding varieties.
They spread rapidly in high tillering varieties producing thick stands,
fields where excessive nitrogenous fertilizers are used, fields which
are continuously flooded and in areas where continuous cropping of rice
is practiced.
The BPH problem is noticed in all rice growing areas of Andhra Pradesh.
Seasonal occurence
The seasonal prevalence of the pest is mostly dependent on the availability
of host plants.
In warm and humid tropics pest remain active throughout the year.
The pest usually occurs in August-September with peak numbers in October
and November and again in February and March in India.
Life history
Insects have a brown body and chest nut brown eyes.
Adult measures 4.0 – 4.5 mm in length - Two types:
Large sized wings not fully developed (Brachypterous)
Fully developed wings extend beyond the length of the body (Macropterous).
These migrate and colonize in new fields.
Settled colonies produce next generation – Females developed
as Brachyupters and make as macropters.
Adult emerge at the base of the stem – mate on the day of emergence.
Brachypters lay 300-350 eggs and Macrophers lay less no. of eggs –
in straight line on the leaf sheath in groups of 2-12. Red eye spot
appear on one end of the egg.
Eggs hatch in 6-9 days – Nymps under 4-5 instars and become adults
in 10-15 days – longevity of adults vary from 18 – 20 days.
Ecology
High humidity and warm temperatures are favorable for build up of
the pest.
The insect prefers irrigated wet land fields to upland rice.
The hatchability of eggs and survival rate of nymphs are maximum around
250C. With in a range of 28 to 30° C.
The population fluctuates according to availability of post plant,
activity of natural enemies and environmental factors.
High nitrogen application leads to faster insect development.
Nature and symptoms of damage
Nymphs and adults congregate at the base of plants, above water level,
and suck plant sap.
In severe infestation the leaves first turn yellow, and later brown
and finally the affected plants dry and die.
The first sign of damage is the sudden slumping of crop in patches
in the field.
The crop in these affected patches dries up giving a scorched appearance
called ‘Hopper-burn’.
Crop drying in patches giving scorched appearance.
Crop loss is usually considerable and complete destruction of crop
occurs in severe cases.
Control measures
Adopt planting with formation of alleys of 25 cm at intervals of 2
Mts to provide good aeration and sunlight.
Avoid dense planting. Planting of 33 hills in kharif and 44 hills
in Rabi
Per Sq.mt may be followed.
Excess application of N fertilizers may be avoided.
In vegetative phase of the crop growth periodical drying and wetting
may be followed for short period to create disturbance in micro climatic
conditions favorable to pest development.
Grow resistant varieties like Chaitanya, Krishnaveni, Chandan, Triguna,
Deepthi, Nandi, Vijeta, Pratitha, Vajram etc.
In developing resistant varieties bio type development has complicated
the effectiveness, sources resistant in one region may be susceptible
in an other region. The susceptibility of IR 26, the first brown plant
hopper, resistant variety released by IRRI in India signaled the evolution
of bio types among hopper populations.
Biological control
Egg parasites like Angrus spp, and nymphal and adult parasites
like Pseudogonatonus spp, were observed to exercise control to
the extent 10 to 40%.
Mirid bugs, Cyrtorlinus lividipennis, is one of the most important
predator of BPH in rice ecosystem.
It provides both eggs and nymphs.
The wolf spider, Lycose Psewdoannulata and some lady beetles and water
bugs were observed as potential predators are found in abundance in
rice ecosystem avoid chemical application and conserve natural enemies.
Chemical Control
Application of Carbofuran 3G @ 25 Kg/ha or spraying of Monocrotophos
36% EC 2.2 ml or carbaryl 50%WP 3 gm or Ethofenprox 10 EC at 1f.5 ml
or BPHC 50 EC at 2 ml or chlorpyriphos 20 EC at 3 ml per litre of water
were found effective.
At the time of milky stage if needed dust Carbaryl 5% @ 25 Kg/ha.
Planting to Pre-Tillering
Spray Carbaryl 0.75 Kg a.i./ha
Monocrotophos, Phosolone, Phosphomidon Or BPHC @ o.5 Kg/ha or Fiprinol
SC @50 gm a.i./ha or Ethofonoprox EC @75 Gm a.i./ha or apply Carbofuran
granules @ o.75 Kg a.i./ha or phorate granules @ 1.25 Kg a.i./ha or
Fiprinol granules @ 75 gm a.i./ha.
Mid-Tillering
As recommended earlier.
Panicle Initiation And Booting
Preferable apply Carbofuran @ 0.75 kg a.i./ha or Phorate granules
@ 1.25 kg a.i./ha or Fipronil granules @ 75 gm a.i./ha or spray as recommended
earlier.
ETL
ETL - Use of appropriate insecticide at the Economic threshold level
(ETL) places pest control on a sound economic basis with minimum ecosystem
disruption.
The gall midge is primarily a pest of low land irrigated rice
but has been reported in upland and deep water rice also.
The extent and severity of gall midge infestation has significantly
increased since 1970’s.
The cultivation of high tillering varieties, intensive management
and low parasitization are conducive to the rapid multiplication
of this pest.
It is distributed in almost all rice growing Asian countries.
In India it occurs as a serious pest in Madhya Pradesh, Manipur,
Orissa, Andhra Pradesh, Bihar, Karnataka and Kerala.
In Andhra Pradesh it’s out-breaks were noticed in Warangal,
Nizamabad, Medak, Khammam, Sreekakulam, Vizag and Vijayanagaram
districts.
About three bio-types were identified in Andhra Pradesh.
Seasonal Occurence
The gall midge attacks rice crop from the nursery to the end of tillering
stage.
The pest remains inactive as a pre-pupa in wild rice or weeds during
dry season.
At the onset of monsoons, it becomes active and completes one to two
generations on grasses before it moves to rice crop.
The incidence is usually high during months of July and August during
which period the maximum tillering takes place.
Young maggots can not survive in plants that pass the vegetative
stage as there are no actively growing apical buds for them to infest.
In some cases, the pest survives on weeds and also in rice stubbles
left after the first crop.
In multiple-cropping areas the fly seldom infests the second crop.
Five to Eight overlapping generations were reported in one season.
Life History
Adult gall midge is similar to female mosquito in appearance.
Soon after emergence moulting take place
Female flies mate only once.
Eggs are laid in singles or groups on the under side near the base
of the rice leaf or on leaf sheath.
Single female is capable of laying 100 – 200 eggs.
Adults are nocturnal in habit and attracted by light.
Male mostly die in 12-18 hours after emergence – while female
live for 3 days.
Eggs are shinning white or pinkish, red or yellow in colour –
elongated tubular and measures 0.55 mm long.
Eggs turn to amber colour before hatching – incubation period
ranges from 3-4 days.
Newly hatched maggots are grey white and fairly stout with a pointed
anterior end.
Larval period is 15-20 days with 3 larval instars.
Pupation takes place inside the galls near the base of the plant.
Pupae have abdominal spines which enable it to wriggle its way to
the tip of gall.
Pupal period varies from 2-8 days .
Adult emergence generally takes place at night or early morning.
Entire life cycle takes about 25-38 days.
Ecology
The pest require high humidity for proper development and hatching
of eggs.
The favorable condition for fly development is 26 to 300C
and 82 to 88 % relative humidity.
Heavy rains or storms cause high mortality.
Early monsoon rains, late planting, prolonged cloudy weather, continuous
heavy rains during July to September were found favorable for rapid
development of the pest in Andhra Pradesh.
Nature and symptoms of damage
Damaged tillers turns into tubular galls which dry off without
bearing panicles.
Main external symptom is SILVER SHOOT or GALL which resembles
onion leaf.
Fully developed gall is a silvery white hallow tube 1 cm wide
and 10 – 30 cm long.
Attack to rice seedlings leads to profuse tillering and these
new tillers often become infested.
Pests starts infestation from seed bed to booting stage in
main field.
Larvae develop only on growing primordia.
Yield loss is 0.5% for every unit percent increase in incidence.
Three bio types are noticed in India – Which are capable
of damaging cultivars, resistant to other populations of the same
species.
Control Measures
Cultural
Adopt early planting adjust planting time so that tillering is completed
before 15th August.
Several workers observed that cultivars with high levels of resistance
to gall midge received no benefit from insecticidal treatment.
Avoid dense planting which increases population.
Removing weeds like Echinochloa colonum, Leersia hexandra, Cynodon
dactylon and Panicum miliaceum etc., which are alternative hosts to
maintain field sanitation.
Avoid excess irrigation.
The pest tend to do more damage and increase in number with excess
fertilization of nitrogen.
Use only recommended doses of Nitrogenous fertilizer.
Uprooting stubbles with deep ploughing soon after harvest is recommended
to avoid hiding larvae.
Biological Control
Platigaster spp is more active in months of October-November and suppresses
the gall midge by parasitization.
Chemical control Dusts and spray formulations are not very
effective against gall midge.
So granular application of insecticides is preferred.
Seedling root dip in Chlorpyriphos also helps in preventing early
infection.
Nursery
Apply Carbofuran or Phorate @ 1kg to 1.25
kg a.i./ha or spray Monocrotophos @ 0.5 kg a.i./ha or Carbaryl 0.75
kg a.i./ha. In endemic areas adopt seedling dip with Chlorpyriphos.
Planting to
Pre-Tillering
& Mid-Tillering
Apply carbofuran 0.75 kg a.i./ha or Phorate,
Quinolphos or Isazophos granules @ 0.6 kg a.i./ha or Fipronil granules
@ 0.75 g a.i./ha.
Economic threshold level (ETL)
Nursery
One Silver Shoot / Sq.mt.
Planting to
Pre-Tillering
One gall /m2 (endemic
areas) or 5 % affected tillers (Non-endemic areas).
The climbing cut worm other wise known as Rice Ear-eating caterpillar
is a minor pest until recently, has become a serious pest in India.
It is distributed in all rice growing Asian countries with
major status in Bangladesh and China.
In India, it is found to cause considerable damage in Andhra
Pradesh, Orissa and Uttar Pradesh.
Occasionally it was found to cause heavy damage to the crop
in Andhra Pradesh.
Seasonal Occurence
The pest has 3-4 generations a year. Adults appear in rice fields
from May onwards and become active from July and November.
The pest occurs in all rice environments but is most abundant in
upland and rainfed wet land environments.
Life History
The adult is a stout, pale red to brown coloured moth which measures
20 mm long with a wing expansion of 40mm.
Moths feed on nectar from flowers and honey dew secreted by Homopterian
insects.
The female moths start egg laying in three days in batches of 100
between leaf sheath and stem.
Newly laid eggs are spherical, greenish white, later turns to pale
yellow and finally black before hatching.
The egg period varies from 5 to 7 days.
Hatched caterpillars are dull white, and later turn to green with
the orange or brown head.
Four longitudinal light grey to black stripes run along the body.
The larvae are nocturnal in habit they hide in loose soil, under trash,
in stubbles, in leaf sheaths and in whorls.
During night, they become active and feed on foliage.
The larval period lasts for about 28 days with 5 to 6 instars.
Pupation takes place in the soil. Sometimes naked pupae are also observed
among the tillers. The pupal period is 8 – 11 days.
Ecology
Heavy rains after a long drought often result in wide spread oviposition
and larval development.
Plants with dense foliage coupled with heavy tillering are mostly
susceptable.
Heavy application of nitrogenous fertilizers also favors the development
of pest, because of the succulence of the plants.
Nature and symptoms of damage
The early instar caterpillars feed on green leaves lemma and
palea of the developing grains as well as anthers of flowers.
Mature larvae, become gregarious and feed voraciously on young
leaves at night.
The final instar larvae cut off rice panicles from the peduncle.
In severe infestations the losses may go upto 60 % or even more.
The pest also feeds on Sorghum and Maize besides feeding on several
weeds like Cynodon dactylon, Cyperus rotundus, Echinochloa colona etc.,
Control Measures
There are no effective biological methods of control to this pest
except removal of alternative hosts in the vicinity of rice fields and
harvesting at the ground level.
Chemical control
Spraying of Monocrotophos at 1.6 ml or Endosulfan 2 ml or Chlorpyriphos
2 ml along with 1 ml of dichlorophos per litre during evening hours
after giving irrigation.
Spray thoroughly with Chlorpyriphos, dichlorophos, Endosulfan or Monocrotophos
@ 0.5 kg a.i./ha during afternoon hours.
Economic threshold levels (ETL)4 to 5 larvae/sq.meter
or 1 larvae/hill.
The rice case worm is an important pest of irrigated and rainfed
wet land rice in South and Southeast Asia.
Besides rice it infests various other grasses and millets.
The pest occurs regularly in low populations, but sporadic increases
in population result in intense defoliation of plants.
It is existing in low population in all rice growing areas of
Andhra Pradesh.
Seasonal occurence
In South India, moth population reach two peaks, one during November
to December and another during May to June.
These peaks coincide with periods of high rainfall and high humidity.
Beyond November, they migrate to grassy areas.
Life history
The adult moths are white in color & about 6 mm long with a wing
expansion of 15 mm.
They live for 4 to 8 days. Males mostly die after mating while females
live longer.
Eggs are laid in one or two adjacent rows in batches of 10 to 20 on
the lower surface of leaves or on the leaf sheath near the water surface.
The average fecundity of female moth is about 50 eggs.
The eggs are circular with light yellow colour. But before hatching
the eggs turn to dark colour with two purplish dots representing the
eyes of developing larva.
The egg period vary from 2 to 6 days.
The newly hatched larva is pale green and measures 1.2 mm long.
Larval period is 20 days with 5 larval instars.
The larva starts feeding shortly after hatching and in about 2 days
it begins to enclose itself in case made from the leaves.
Feed on the leaves while remaining in case.
full-grown larva attaches its leaf case to the rice stem slightly
above the water level, closes the upper and lower ends of the case and
undergoes pupation.
The pupa is about 5.5mm long cream coloured and later turns to silvery
white.
Pupal period is about a week.
EcologyVariations in temperature have no relationship with pest population.
Infestation is more on heavy tillering and high yielding varieties.
Nature and symptoms of damage
The pest attacks the crop in the early transplanted stage.
The leaf blade is cut into small bits and a tubular case is
constructed by larva.
The larva feeds by scraping under surface of the leaf blade.
Upper epidermis surface of the leaf is intact
White patches are seen on the leaf blades.
Tillers become stunted and loose their vigour and often the plants
are killed.
Control measures Cultural control
A rope may be passed over the young crop for dislodging the larval
cases from the tillers and then the water may be drained for eliminating
them.
Chemical control
Drain water from the field and spray Endosulfan, Monocrotophos or
Carbaryl @ 0.5 kg a.i./ha or dusting may be adopted with Carbaryl @
30 kg / ha.
Several species of Hydrellia exist in Rice ecosystem . The pest
occurs in India, Bangladesh, Indonesia, Taiwan, Thailand and Phillippines.
The pest is more abundant in Rice crop grown with continuous standing
water. In AP it is found as occasional pest in Rice fields.
Seasonal occurence
It is usually found from August to October months in Andhra Pradesh.
The pest is abundant during early stages of crop growth.
The infestation ceases at the panicle emergence stage.
Life History
The adult flies are dull-grey coloured.
The female fly measure 1.8 to 2.3 mm long.
Cylindrical and whitish coloured eggs are laid singly on either surface
of the leaves.
The incubation period ranges from 2 to 6 days.
Newly hatched maggots are transparent to light cream in colour and
later turn to yellow.
Maggots migrate to un open central leaves and remain there during
entire larval period.
The full-grown larva is cylindrical in shape with posterior end tapering
to a pair of pointed spiracles.
It measures about 7 mm long.
The larval period is about 10 to 12 days.
Light to dark brown, pupa and measures 4 to 5 mm long – pupates
outside feeding stalk.
Pupal period is 7 to 10 days within a whole life cycle period of 26-28
days.
Nature and symptoms of damage
The maggots attack the leaf blades even before uncurling and
the initial damage is characterized by the presence of narrow
stripes of whitish area in the blade margins.
Heavy infestation causes a marked stunting of the plant and
reduction of tillers.
Control measures
Chemical
Apply Phorate 10 G @ 10 kg / ha or Carbofuran 3 G @ 25 kg / ha or
spray Fenitrothion 50 EC at 0.1 % (2 ml/lit).
Apply Carbofuran granules @ 0.75 kg a.i./ha or Fipronil granules @
75 g a.i./ha.
Detailed Study of Insects
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