Effects of nootkatone and a borate compound on formosan subterranean termite (Isoptera : Rhinotermitidae) and its symbiont protozoa

Wood treated with disodium octaborate tetrahydrate, with nootkatone, a natu ral extract isolated from vetiver oil, or with both nootkatone and disodium octaborate tetrahydrate was tested for effects on Coptotermes formosanus S hiraki and its hindgut flagellates. Results demonstrated that after 7 d dis odium octaborate tetrahydrate-treated wood induced high termite mortality a nd almost complete loss of flagellates, confirming the toxicity of borates to these termites. Wood treated with nootkatone alone or with the nootkaton e-borate mix was consumed in significantly lower amounts than the control, and termite survival was comparable to results obtained for starved termite s. A significant progressive reduction in the total number of protozoa was observed for all groups, including the controls. We conclude that nootkaton e acts as a feeding deterrent, inducing starvation that results in almost a complete loss of Pseudotrichonympha grassii Koidzumi, the most important f lagellate species for cellulose digestion in this termite.