RESIDUAL TOXICITY AND REPELLENCY OF ESSENTIAL OILS TO STORED-PRODUCT INSECTS

Residual toxicity and repellency of essential oils of Pimpinella anisu m L., Eucalyptus camaldulensis Dehn., Thymbra spicata L. var. spicata and Satureja thymbra L, was investigated. Only essential oil of P. ani sum showed high residual toxicity to Tribolium confusum du Val adults causing a mortality over 95 % after a 5 days' exposure. All essential oils repelled Sitophilus oryzae (L.) adults in food preference tests. P. anisum was the most repellent one as only 0-7.2 % of the test insec ts preferred the treated food. It was followed by E. camaldulensis, T. spicata var. spicata and S, thymbra in which 5.2-17.4 % of the test i nsects settled in the treated food. In area preference tests with T. c onfusum adults, repellencies over or about 50 % were retained for 2 we eks with the essential oils other than E, camaldulensis, in the latter a 50 % repellency lasted 4 weeks. All essential oils gave repellencie s falling into the range of promising repellents, that is, presumably, a 40.1-60 % repellency as an overall average of an 8 weeks exposure.