Three Insect Pests of Rice

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1 Three Insect Pests of Rice
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2 Introduction India has largest area of 44.3 million ha under rice cultivation and stands second in production around million t. Yield loss due to insect pests in rice in India is estimated to the tune of 25%. Next

3 Introduction End Previous 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. End Previous Next

4 End Previous Swarming Caterpillar Caseworm Click on the picture
Rice Grasshopper Click on the picture End Previous

5 Caseworm Nymphula depunctalis
Identification Caseworm adults are small sized delicate moths with white wings and pale brown spots. Larva Caseworm adult Source: knowledgebank.irri.org Larvae are semi-aquatic and possess six rows of gills on the dorsal side of the body. End Previous Next

6 Caseworm Nymphula depunctalis
Identification 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. End Previous Next

7 Caseworm Nymphula depunctalis
Identification Caseworm is commonly found in irrigated and rain fed wetland rice fields with poor drainage. Transplanting young seedlings favor the incidence of caseworm larva. Floating leaf cases Source: knowledgebank.irri.org End Previous Next

8 Caseworm Nymphula depunctalis
Nature of damage 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. End Previous Next

9 Caseworm Nymphula depunctalis
Nature of damage 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. End Previous Next

10 Caseworm Nymphula depunctalis
Nature of damage 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. 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. End Previous Next

11 Caseworm Nymphula depunctalis
Management Following cultural practices can minimize the damage. Draining the field Wider spacing (30 x 20 mm) Early planting Planting older seedlings Correct application of fertilizers. End Previous Next

12 Caseworm Nymphula depunctalis
Management Among the biological agents: Snails are useful predators of eggs of the rice caseworm. Spiders, dragonflies, and birds eat the adults. There is a nuclear polyhedrosis virus, which is a potential control agent against the rice caseworm. End Previous Next

13 Caseworm Nymphula depunctalis
Management The larvae are highly sensitive to insecticides. The use of foliar treatments of carbamate insecticides can control the insect pest. Pyrethroids should be avoided as they can cause secondary problems, such as brown planthoppers.  End Previous Back

14 Rice Grasshopper Hieroglyphus banian End Previous Next 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. Rice grasshopper Nymphs resemble adults except that they lack wings. End Previous Next

15 Rice Grasshopper Hieroglyphus banian End Previous Next
Nature of damage Both adult and nymphs feed on rice foliage. In severe incidence they consume the leaves leaving midribs and stalks (Fig.). End Previous Next

16 Rice Grasshopper Hieroglyphus banian End Previous Back 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 . Raking of field bunds during summer to destroy the egg pods is an extremely important for grasshopper management . End Previous Back

17 Swarming Caterpillar Spodoptera mauritia
Identification Adult is a medium sized, stout, grey-brown moth with black spots on forewings while its hind wings are whitish brown. Adult moth End Previous next

18 Swarming Caterpillar Spodoptera mauritia
Identification Larvae are stout dirty whitish brown and more than one can be seen at the bases of plants during day time. Female moth lays eggs in clusters on rice and wild grasses and covers them with grayish hairs. Larvae End Previous next

19 Swarming Caterpillar Spodoptera mauritia
Nature of Damage Larvae damage the crop. In the nursery the seedlings are cut and completely eaten up (Fig.) as if grazed by cattle. In the main field, they denude the plants of their foliage leaving behind midribs. Incidence of this pest has been found to be more after heavy rains or after floods. End Previous next

20 Swarming Caterpillar Spodoptera mauritia
Management Add kerosene to irrigation water to suffocate the larvae. Allow the ducks in the nursery to pick up the larvae and eat. Spray chloro pyriphos 20 EC or endosulfan 35 EC 80 ml+ 20 l of water in 80 cents End Previous Back

21 Swarming Caterpillar (Sc. N.Spodoptera mauritia)
Nature of damage Drain the water Add kerosene to irrigation water to suffocate the larva Allow the ducks in the nursery. ter Spray chloro pyriphos 20EC or endosulfan 35 EC 80 ml+ 20 l of water in 80 cents Next