Susceptibility of neem to attack by the Formosan subterranean termite, Coptotermes formosanus Shir. (Isopt., Rhinotermitidae)

Abstract

AbstractThe neem tree, Azadirachta indica, is a source of natural compounds with potent insecticidal, feeding deterrent and insect growth regulator activity. However, little information is available on the effects of these natural products on termites. We assessed the effects of mulches made from ground neem branches and roots on survival of the Formosan subterranean termite, Coptotermes formosanus, and compared termite feeding and survival on neem wood and bark to that on susceptible Pseudotsuga menziesii wood. Termite survival was fairly low in both P. menziesii heartwood and neem mulches over the 14 day test period, and did not differ significantly among those treatments. However, termites exposed to either P. menziesii wood, neem wood, or neem bark for 4 weeks fed significantly less on neem wood and bark. Feeding on neem bark caused significant termite mortality (56.4%) in comparison to that induced by feeding on neem wood (27.1%) or P. menziesii wood (12.5%). Thus, although neem is not entirely resistant to termite attack, the antifeedant properties of its wood and bark and the toxicity of neem bark support the use of neem trees for arboriculture in areas where termites are a problem.