Three Insect Pests of Rice Next. Three Insect Pests of Rice Introduction India has largest area of 44.3 million ha under rice cultivation and stands second.

ThreeInsect Pests

of Rice

Next

Three Insect Pests of Rice

Introduction

India has largest area of 44.3 million ha under rice cultivation and stands second in production around 89.09 million t.

Yield loss due to insect pests in rice in India is estimated to the tune of 25%.

Next


There are over 800 insect species damaging rice in one way or another but in tropical Asia only about 20 species are of major importance and of regular occurrence.

Caseworm, Swarming caterpillar and Grasshoppers are important pests of rice.

Introduction

Next

Previous

End


Caseworm

Swarming Caterpillar

Click on the picture

Rice Grasshopper

Previous

End


Caseworm Nymphula depunctalis

Caseworm adultSource: knowledgebank.irri.org

Identification

Caseworm adults are small sized delicate moths with white wings and pale brown spots.

Larvae are semi-aquatic and possess six rows of gills on the dorsal side of the body.

Larva

Next

Previous

End


The larva encloses itself within tubular case made by cutting pieces of leaf blade and thus leaf tips have cut ends (Fig.).

Enclosed within the case, the larva attaches itself to the rice plant and feeds on the leaves. The cases are also seen floating in water.

Next

Caseworm Nymphula depunctalis Identification

Previous

End


Caseworm is commonly found in irrigated and rain fed wetland rice fields with poor drainage.

Transplanting young seedlings favor the incidence of caseworm larva.

Caseworm Nymphula depunctalis Identification

Floating leaf casesSource: knowledgebank.irri.org

Next

Previous

End


caseworm occurs regularly in low populations but sporadic outbreaks result in intense defoliation of plants causing severe loss in early vegetative stage.

Larvae damage the crop by scrapping leaf tissue, leaving only the papery upper epidermis.

Caseworm Nymphula depunctalis Nature of damage

Next

Previous

End


The larva scrapes the green tissue of the leaf with only the white epidermis remaining.

The white epidermis appears ladder-like because of the back and forth motions of the larval head during feeding.


Next

Previous

End


Feeding damage includes cutting of leaf tips to make leaf cases.

The damage may result in patches of severe defoliation, stunted growth and death of plants.


Next

Previous

End

The rice plants can recover from the damage if there are no other defoliators present. However, maturity may be delayed for 7 to 10 days.


Following cultural practices can minimize the damage.

Draining the field


Management

Next

Previous

End

Planting older seedlings

Wider spacing (30 x 20 mm)

Early planting

Correct application of fertilizers.


Among the biological agents:

Snails are useful predators of eggs of the rice caseworm.


Management

Next

Previous

End

Spiders, dragonflies, and birds eat the adults.

There is a nuclear polyhedrosis virus, which is a potential control agent against the rice caseworm.


The larvae are highly sensitive to insecticides.

The use of foliar treatments of carbamate insecticides can control the insect pest.


Management

Back

Previous

End

Pyrethroids should be avoided as they can cause secondary problems, such as brown planthoppers.


Rice grasshopper

Identification

Several species of grasshopper infest the rice crop but Hieroglyphus is the most important one.

Adults are greenish hopping insects (Fig.) creating sound through their movements in the crop.

Nymphs resemble adults except that they lack wings.

Rice Grasshopper Hieroglyphus banian

Next

Previous

End


Nature of damage

Both adult and nymphs feed on rice foliage.

In severe incidence they consume the leaves leaving midribs and stalks (Fig.).


Next

Previous

End


Management

Towards the end of crop season, females lay eggs in egg pods along the sides of bunds surrounding the field.

Eggs hatch in 2 to 3 weeks after the onset of monsoon. There will be only one generation in a year .


Back

Previous

End

Raking of field bunds during summer to destroy the egg pods is an extremely important for grasshopper management .


Identification

Adult is a medium sized, stout, grey-brown moth with black spots on forewings while its hind wings are whitish brown.

Swarming Caterpillar Spodoptera mauritia

nextPrevious

End

Adult moth


Identification

Larvae are stout dirty whitish brown and more than one can be seen at the bases of plants during day time.


Previous

End

Larvae

Female moth lays eggs in clusters on rice and wild grasses and covers them with grayish hairs.

next


Nature of Damage

Larvae damage the crop. In the nursery the seedlings are cut and completely eaten up (Fig.) as if grazed by cattle.


Previous

End

In the main field, they denude the plants of their foliage leaving behind midribs.

next

Incidence of this pest has been found to be more after heavy rains or after floods.


Management

Add kerosene to irrigation water to suffocate the larvae.


Previous

End

Allow the ducks in the nursery to pick up the larvae and eat.

Back

Spray chloro pyriphos 20 EC or endosulfan 35 EC 80 ml+ 20 l of water in 80 cents

Drain the water

Add kerosene to irrigation water to suffocate the larva

Allow the ducks in the nursery.

Spray chloro pyriphos 20EC or endosulfan 35 EC 80 ml+ 20 l of water in 80 cents

Nature of damage

Swarming Caterpillar (Sc. N.Spodoptera mauritia)Swarming Caterpillar (Sc. N.Spodoptera mauritia)

Next

Three Insect Pests of Rice Next. Three Insect Pests of Rice Introduction India has largest area of 44.3 million ha under rice cultivation and stands second.

Documents