Distribution pattern and lifetable of stem borer Chilo partellus on maize

Distribution pattern and lifetable of stem borer Chilo partellus (Swinhoe) was studied on maize, which revealed that of the 10 plants only 4–6 plants were chosen by the female moth for oviposition. The distribution pattern of eggs showed that most eggs were laid inthe first leaf sheath (107±0.55) followed by the second (75.33±1.72), with the least on the basal leaf sheath (47.10±0.55). Maximum eggs (95.33) were laid two days after the emergence of adult. The larvae were observed scattered from the seedling to early vegetative stage with distribution being contagious in nature around 22 to 71 days old crop. Lifetable analysis revealed that there was 42% egg mortality due to unknown factors and 19.54% failed to hatch, with 36.17% surviving to larva. Larval mortality was observed due to unknown factors and parasitisation with larval parasitoids; while in pupae it was due to diseases (11.76%). Due to biotic and abiotic factors the mortality of C. partellus was of a K value of 0.88.