Insect Physiology Laboratory, Section of Entomology, Department of Zoology, Aligarh Muslim University, Aligarh-202 002, Uttar Pradesh (India).
An ecdysteroid, 2, 22, 25-trideoxy-5P-hydroxyecdysone was evaluated against the early 5th instar larvae of Spilosoma obliqua Walker through topical and ingestion methods. Observations on fecundity and fertility of females emerging from treated as well as control stocks were recorded. The topical application revealed no significant effect on the reproductive potential of females as compared to the oral administration of this hormone where the effect was significantly pronounced. Even the highest selected dose i.e., 40 μg/5th-instar larva, when applied topically could reduce fecundity and fertility by 10.14 and 4.72%, respectively. On the other hand, this dose through ingestion caused the respective reduction by 43.85 and 27.97%. The analogue was effective in checking the population of S. obliqua Perhaps, this analogue of β ecdysone may find use in integrated control programme of polyphagous Bihar hairy caterpillar.
