Toxicity of pine resin derivatives to subterranean termites (Isoptera: Rhinotermitidae)

Abstract

In the search of alternatives for conventional fungicides and insecticides, the use of natural plant products for the protection of wood is one of the most appealing fields of work. Dehydroabietic acid, the main compound of dismutated rosin, a renewable raw material from Portuguese forests, and some of its derivatives, were recognized as having bactericidal, fungicidal or fungistatic properties that could eventually be used for wood protection. The work presented here is part of a project aimed at developing this possibility and to extend that action to insects, namely termites, as diterpene acids have been reported to be antifeedants against aphids and sawflies and several other similar products have been studied for the same end‐use. Pine resin and eight of its derivatives were bio‐assayed to test for termiticidal activity and to assess the LC50 of the compounds, whenever toxic activity was recorded. A comparison was made with the activity of an established termiticide, boron. There was a high degree of variation between the products tested: resin, resinate, resinol, dehydroabietic acid and trans‐deisopropyldehydroabietanol showed negligible activity; dehydroabietanol and cis‐deisopropyldehydroabietanol showed activity at higher concentrations; two mixtures of cis‐/trans‐deisopropyldehydroabietanol had a promising performance in terms of anti‐termite activity and will be further evaluated. This paper presents results that will contribute to the development of new termiticides from a renewable resource and with better behaviour towards the environment.