Contact and fumigant activities of constituents of Foeniculum vulgare fruit against three coleopteran stored-product insects

The insecticidal activities of materials derived from the fruit of fennel, Foeniculum vulgare, against adults of Sitophilus oryzae, Callosobruchus chi nensis and Lasioderma serricorne were examined using direct contact applica tion and fumigation methods. The biologically active constituents of the Fo eniculum fruits were characterized as the phenylpropenes Q-anethole and est ragole, and the monoterpene (+)-fenchone, by spectroscopic analysis. Respon ses varied with insect species, compound, dose and exposure time. In a filt er paper diffusion test, estragole at 0.168 mg cm(-2) caused 91% mortality to S oryzae adults within 1 day after treatment (DAT), whereas (+)-fenchone and Q-anethole gave over 90% mortality at 2 and 4 DAT, respectively. Again st C chinensis adults, all test compounds revealed potent insecticidal acti vities at 0.021 mg cm(-2) at 2 DAT. Against L serricorne adults at 0.105 mg cm(-2), (E)-anethole gave 100% mortality at 1 DAT, whereas 90 and 60% mort ality at 4 DAT was achieved with estragole and (+)-fenchone, respectively. In a fumigation test, the test compounds were much more effective against a dults of S oryzae, C chinensis and L serricorne in closed cups than in open ones, indicating that the insecticidal activity of test compounds was larg ely attributable to fumigant action. As naturally occurring insect-control agents, the F vulgare fruit-derived materials described could be useful for managing field populations of S oryzae, C chinensis and L serricorne. (C) 2001 Society of Chemical Industry.