Effect of Bast Fibre Crops and Their Biochemicals on Nutritional Indices of Spilosoma Obliqua (Walker)

This study is on the nutritional efficiency of the host plants viz., Corchorus olitorius, C. capsularis, Hibiscus cannabinus, H. sabdariffa, Crotoloria juncea and Boemheria nivea and their biochemical influences on Bihar hairy caterpillar Spilosoma obliqua (Walker) (Lepidoptera: Arctiidae). The results revealed that the nutritional and biochemical parameters varied significantly with the infested and uninfested host plants. The growth rate of 5th instar larvae varied from 13.06 mg/ day in B. nivea to 17.90 mg/ day in C. olitorius; it was 14.80 ± 0.69, 16.74 ± 0.74, 14.94 ± 0.29 and 15.06 ± 0.26 mg/ day on C. capsularis, H. cannabinus, H. sabdariffa, C. juncea and B. nivea, respectively. Thus, C. olitorius appeared to be the most suitable food source for growth and development of S. obliqua. Peroxidase and polyphenol oxidase were elicited by the infestation of S. obliqua indicating their role in insect defence. Higher phenol and peroxidase content in the host plants adversely affected the food utilization indices. This is the possible explanation for variation in food consumption and development of S. obliqua; and it might be due to significant differences in the biochemical contents of the evaluated bast fibre crops.