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.
Seasonal
occurance
It occurs both in
kharif and rabi seasons.
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 and 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, that too 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 postponed.
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.
Spray Chlorpyriphos 2 ml /lit or Phosphomidan 1 ml /
lit. is required repeat the same at 10-15 days. OR Apply Cartap Hydrochloride
4 G @ 8 Kg / acre OR Carbofuran 3G @ 10 Kg / acre
Recommendation based on crop growth Stage
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 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 ml OR Quinalphos 2.5 ml or Carbary
l 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 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 OR Cartap hydrochloride 4
G @ 20 Kg / ha.
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.
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.
Matured 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, Chlorpyriphos, Quinalphos, Phasphomidon
or Phosalone @ 0.5 kg a.i./ha or apply Cartap WP @ 300 gms a.i./ha
or Fipronil SC @ 50 gms a.i./ha or Cartap 4 G @ 1.0 kg a.i./ha.
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.
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.
Dusting of Malathion @ 30 kg/ha or spraying Monocrotophos
or Endosulfan or Carbaryl @ 0.4 kg a.i./ha during after-noon hours.
The leaf hopper gained economic significance as regular pests
of rice.
The leaf hoppers attack all the aerial parts of rice plant.
T
his 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.
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 is 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 25 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.
Recommendation Based on Crop Growth Stage
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.
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.
Pancile Initation 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
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.
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.
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.
Grow resistant varieties. 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 Carbofuron or Phorate @ 1kg to 1.25 kg a.i./ha
or spray Monocrotophos @ 0.5 kg a.i./ha or Carboryl 0.75 kg a.i./ha.
In endemic areas adopt seedling dip with Chlorpyriphos.
Planting
To :
Pre-Tillering
& Mid-Tillering
Apply carbofuron 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.
- 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.
Ecology
Variations 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 Carboryl @ 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.
Seasonal occurence
It is usually found from August to October months.
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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