Effect of neem seed oil fumigation on wood-destroying insect

As the deadline for phasing out the use of conventional synthetic chemicals as fumigant approaches, alternative fumigants are being evaluated. Fumigants from plant origins could have greater potential in future on the basis of their efficacy, economic value and use in large scale storage. Several aromatic plants are being investigated for their antifeedant and insecticidal activity including their fumigation action. In the present study, neem seed oil (Nso) was extracted and used at different concentrations. Wooden blocks of hard and soft woods were fumigated with six concentrations of Nso and exposed to Lyctus africanus Lesne larvae. Nso has emerged as promising alternative of synthetic fumigants. The present study showed that Nso is an effective fumigant for the control of Lyctus larvae at all concentrations tested. The lowest concentration showed 48% mean mortality, while 1·6% caused >85% mortality of Lyctus larvae. On the basis of probit analysis, it was observed that the LC50 of Nso for L. africanus is 0·048–0·05% in both woods.