We examined the behavior of Formosan subterranean termites toward one of th
e components of vetiver grass oil, the roots of which manufacture insect re
pellents. We found nootkatone, a sesquiterpene ketone, isolated from vetive
r oil is a strong repellent and toxicant to Formosan subterranean termites.
The lowest effective concentration tested was 10 mug/g substrate. This is
the first report of nootkatone being a repellent to insects.