Friday, October 4, 2013

Insect Pest Of Rice: Rice Hispa

symptoms of infested field
rice hispa

Rice Hispa ( Scientific name is Dicladispa armigera ) is major insect pest of rice. Rice hispa belongs to the Chrysomelidae family of Coleoptera order. Both adults and grubs are destructive to rice crops. Mainly leaf blade of rice plants are damaged by them. By this way photosynthesis is hampered and yield is reduced.

Nature of Damage:
The upper surface of leaf of rice plants is scraped by the adult insects. Sometimes it is seen that only lower epidermis of the leaves remains to eat! So many white streaks that are parallel to the midrib are appeared at the damage areas. Tunnels are made between two epidermal layers by grubs. By this way irregular translucent white patches are created by the grubs. These translucent white patches stared from the tips of the leaves to the base of the leaf blades. Leaves becomes whitish and finally dry off if severe infestation is occurred. So the photosynthesis area of plants is reduced and plants become stunted due to lack of foods. The number of grains is reduced and grains are not well filled. 

Control measures:
1. Cultural control is good control measures for rice hispa.
a. In off season rice hispa feed and breed on the grasses or weeds near the rice fields. So must manage the weeds that are present in farm or rice fields.
b. Ratooning of rice plants must be avoided and stubble should be uprooted so that rice hispa cannot take shelter during off seasons.
c. Optimum dose of N fertilizer should be applied.
d. Early varieties may be cultivated to avoid rice hispa buildup.
e. Tip of the leaves should be pick out when rice hispa are seen on the leaf tips.
f. Infested leaves must be removed until plants go to booting stage.
g. During transplanting infested leaves of seedlings must be removed.
2. Resistant varieties must be cultivated.
3. Biological control of insects or pests are appreciated at first than chemical control.
a. Many ichneumonid wasps and braconid wasps are parasitoids of the larvae of rice hispa. So we may increase the population of these parasitoids in rice fields.
b.  Rhinocoris fuscipes is a predator of adult rice  hispa. So we may consider this predator to control rice hispa.
4. Chemical control is always discourage by scientist and agriculturist. If we manage our fields properly, chemical control is not needed. We may go for chemical control when severe attack is happened. We can apply Fenitrothion at the rate of 454ml per acre, Dimethoate at the rate of 454 ml per acre and carbaryl at the rate of 688g per acre.

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