Volatile activity of plant essential oils against stored-product beetle pests.

Abstract The insecticidal effects of a group of plant essential oils (caraway, coriander (Coriandrum sativum), sweet basil (Ocimum basilicum) and garland chrysanthemum) were studied against the damaging legume and cereal storage pests Callosobruchus maculatus and Sitophilus granarius. Volatile toxicity was recorded by setting up a bioassay, with experimental units of 0.5 litres, which took into account the pest, the mode of oil application (vapours only, avoiding direct contact) and the stored product. Caraway oil was the most effective, causing 100 and 60% mortality in C. maculatus at 10 µl and 1 µl respectively, while 25 µl was needed to kill 68% of S. granarius adults. Other oils, such as coriander (10 µl) and sweet basil (25 µl), showed activity only against the bruchid. The practical use of such plant derivatives for stored product protection is discussed.