Role Of Volatile Semiochemicals In Host Orientation And Host Habitat Location Of Parasitoid Trichogramma Ostriniae (Hymenoptera: Trichogrammatidae)

Olfactory response of an egg parasitoid wasp. Trichogramma osrriniae. to the voiatiles from 14 varieties of mungbean (T'Ygna radiata), 1 sweet corn hybrid.female moths and eggs of the host insect. Asian corn borer (ACB). Qsirinia furnacalis (Guenee). were studied in laborator~'. Volatiles from mungbean leaves and ACB egg masses was identified by using headspace GC-MS. Activebioassa's of the components from volatiies of mungbeans and egg masses of ACB to T ostriniae females were carried out in laboratory. Mechanisms ofattraction and augmentation function of some creeping type mungbean for Iostriniae were discussed in this paper. The results are as follows:Volatiles emitted from different parts of mungbean and corn plants wereextracted by a se if-designed device. Olfactory responses of I ostriniae to thevolatiles were measured by a four-armed olfactometer. Results indicated that Iostriniae was attracted to the most of creeping type mungbean plants voiatiies.such as Do660. Do686. Do658. Higher attraction was observed in volatiles fromwhole plants and leaves of some creeping type mungbean. None tested erectingtype mungbean plants volatiles could elicit any response. I. ostriniae females didnot show any response to the volatiles from flowers of tested creeping anderecting type mungbeans. The female wasps only showed lightly response to thevolatiles of young tassels, but no response to leaves and silks from sweet corn.The chemical components and their ratios of volatiles from two creeping typernungbean varieties, Do660. Do686. one erecting type mungbean. Zhonglul andACB egg masses were identified by using headspace GC-MS. Relative amount ofHexadecaonic acid in three varieties of mungbean is 14.6%. 17.3%. 50.3%.respectively, and evidently higher than other compounds. The compound ofDiethvl phthalate is only in creeping type mungbean.Olfactory response of T ostriniae to main volatile compounds was studied.Results indicated that wasps had no response to Tetradecane. Pentadecane.Hexadecane. Heptadecane. Octadecanoic acid and Oleic acid. even significantlynegative to Tetradecane. I ostriniae showed strong response to Diethvl phthaiateM.S. ThesisABSTRACTwhich was only in the creeping type munbean. Hexadecanoic acid also increasedthe retention time and entering times of T ostrintaeOlfactory response of T. ostriniae to volatiles emanating from the differentstages of ACB females, their accessory gland and eggs were measured. It havebeen demonstrated that airborne chemicals from egg masses, (E)- 1 2-tetradecenylacetate (E12- 14:Ac) (main individual component of ACB sex pheromone),mated-female moths before their first oviposition and their accessory glands stimulated an intensive search behavior by T. ostriniae females, on the other hand,volatiles from virgin or females tested after their first oviposition and their accessory glands did not incite the parasitoid's movement.