Bio-Ecology of Lepidopteran Pests and Natural Enemies in Rice Ecosystem of Balaghat District

In India, tentatively 100 insects have been reported as pests of rice and 20 of these are accepted to be key pests causing more than 30% yield loss from germination to harvest of the crop. The stem borers and leaf folders both are of economic importance and they damage the rice plants at all the stages of crop growth and are the key factors responsible for poor rice yield. In view of the above background the present experiments were conducted to study on “Bio-ecology of stem borer and leaf folder in rice ecosystem of Balaghat district” to find out the seasonal incidence and species diversityof stem borer and leaf folder with natural enemies in rice ecosystem. The highest mean percent dead heart and white ear head caused by stem borer were recorded in Mehandiwada village of Waraseoni and lowest percent were recorded in Belgoan village of Lallburra. Whereas, the maximum percent damaged leaves caused by leaf folder was recorded in Bakoda village followed by Mohgaon village (5.17% DL) of Lalburra block and minimum percent damaged leaves (4.39%) was recorded in Savngi village of Waraseoni block followed by Sihora (4.50% DL) village of Lalburra block and Kope (4.55% DL) village of Waraseoni block. The total numbers of five natural enemies i.e. hymenoptera wasp, orthoptera grasshoppers (meadow grasshopper), odonata fly (dragonfly and damselfly), hemipteran bugs and spider were observed at different stages of crop growth. Among natural enemies, the abundance was in the order of meadow grasshopper > Odonata fly >hymenoptera wasp > spider > hemipteran bugs. The three species of stem borer i.e. Scirpophaga insertulas, Sesamia inferens and Scirpophaga innotata were observed in Balaghat district Among all three species of stem borer, the highest population was recorded with Scirpophaga insertulas (71.24%) and followed by Sesamia inferens (20.61%) and Scirpophaga innotata (8.16 %). The three species of rice leaf folder i.e. Cnaphalocrosis medinalis, Marasmia patnalis and Marasmia ruralis were observed in Balaghat district. Among all three species of leaf folder, the highest population (85.16%) was observed with C. medinalis followed by M. patnalis 12.38% and M. ruralis 2.46%.