Fumigant toxicity of neem (Azadirachta indica A. Juss.) seed oil volatilesagainst pulse beetle, Callosobruchus maculatus Fab. (Col., Bruchidiae)

Neem seed extracts and the pure compound present therein have been evaluate d for various biological effects on insect and other pests. There is, howev er, perhaps no report on the evaluation of isolated neem seed volatiles aga inst insect pests. Neem seed volatiles were isolated from need seed oil and evaluated for their bioactivity against eggs, 2- and 15-day-old grubs and adults of pulse beetle, Callosobruchus maculatus. All stages were found sus ceptible to different doses of volatiles. At 200-50 mu l it caused 100-81.6 % and 100-25.4% mortality of adults and grubs respectively. Eggs when expos ed to 10-200 mu l dose for 3 days failed to hatch. At a 50 mu l dose with a 5-day exposure period the eggs that hatched failed to reach adult stage an d terminated as grubs. The adults were found most susceptible followed by g rubs and eggs. The effects of the volatiles was time-dependent.