Evaluation of vetiver oil and seven insect-active essential oils against the formosan subterranean termite

Betty C.R. Zhu, Louisiana State University
Gregg Henderson, Louisiana State University
Feng Chen, Louisiana State University
Huixin Fei, Louisiana State University
Roger A. Laine, Louisiana State University


Repellency and toxicity of 8 essential oils (vetiver grass, cassia leaf, clove bud, cedarwood, Eucalyptus globules, Eucalyptus citrodora, lemon-grass and geranium) were evaluated against the Formosan subterranean termite, Coptotermes formosanus Shiraki. Vetiver oil proved the most effective repellent because of its long-lasting activity. Clove bud was the most toxic, killing 100% of termites in 2 days at 50 μg/cm 2. The tunneling response of termites to vetiver oil also was examined. Vetiver oil decreased termite tunneling activity at concentrations as low as 5 μg/g sand. Tunneling and paper consumption were not observed when vetiver oil concentrations were higher than 25 μg/g sand. Bioactivity of the 8 oils against termites and chemical volatility were inversely associated. Listed in decreasing order of volatility, the major constituents of the 8 oils were: eucalyptol, citronellal, citral, citronellol, cinnamaldehyde, eugenol, thujopsene, and both α- and β- vetivone. Vetiver oil is a promising novel termiticide with reduced environmental impact for use against subterranean termites.