PrintSend to friend
1. Gall midge (Orseolia oryzae) is a serious pest in Manipur and also occurs throughout the region as a common pest.
2. It is found in both lowland and upland conditions during the tillering stage of the rice plant. It has also been reported to occur in deep water rice in Assam.
3. Its Population density is favoured mainly by cloudy or rainy weather, cultivation of high tillering varieties, intensive management practices and low parasitization.
4. The adults are nocturnal and they can easily be Collected using light traps. They mate soon after emergence. Each female midge mates only once. It can lay as many as 100-200 eggs in its lifespan of 4 days.
5. The male midge lasts for 12-18 hours soon after emergence. larval and pupal development is completed inside the gall. One maggot occupies one tiller, Three to four larval stages are observed in 14-20 days. Pupation takes 2-7 days. Before adult emergence, the pupa uses its abdominal spines to reach the top of the gall.
6. The feeding causes formation of a gall called 'silver' or 'onion' shoots. It makes exit holes for adult emergence. During the dry season, the insect remains dormant as a pupa in dormant buds of alternate host.
7. Rice gall midge is parasitized by six hymenopterous parasitoids like Tetrastichus sp., Ceratosolen sp., Aneristus ceroplastate, Cocophagus sp., C. tschirchi, Metaphyars sp. under normal conditions and control the pest to the extent of 50%.