ATTRACTION OF FEMALE ORIENTAL FRUIT-FLY, BACTROCERA-DORSALIS, TO VOLATILE SEMIOCHEMICALS FROM LEAVES AND EXTRACTS OF A NONHOST PLANT, PANAX(POLYSCIAS-GUILFOYLEI) IN LABORATORY AND OLFACTOMETER ASSAYS

Fresh whole leaves and solvent-water leaf extracts of the hedgerow pla nt panax, Polyscias guilfoylei (Bull), were tested for their attractiv eness to male and female Oriental fruit flies, Bactrocera dorsalis, in laboratory flight tunnel and cage olfactometer bioassays. Fresh matur e whole panax leaves were found to be attractive to mated female orien tal fruit dies in the flight tunnel. Response of males and virgin fema les was low and in most instances not significantly different from con trols. Attraction of mated female flies to the layers resulting from a methylene chloride-water partition or a hexane-water partition of fre shly ground leaves using small McPhail traps was greatest in the methy lene chloride fraction. When methylene chloride and water layers were tested competitively in a multiple-choice rotating olfactometer, the m ethylene chloride fraction was more attractive. Tests involving the me thylene chloride-water interface (an emulsion of the two partitioned l ayers) with and without a standard attractant NuLure, showed the emuls ion layer to be significantly more attractive than the other fractions or NuLure. In outdoor cage olfactometer assays of methylene chloride and water fractions, activity was greatest in the methylene chloride f raction. The results suggests that volatile semiochemicals from this n onhost plant are attractive to mated female Oriental fruit flies. The results are discussed in relation to the chemical ecology of B. dorsal is and the potential use of this nonhost plant for detection and contr ol of female Oriental fruit flies in the field.