Effect of entomopathogenic fungus, Beauveria bassiana (Ascomycota, Hypocreales) on foraging behaviour of parasitoid wasp, Aphidius matricariae (Hym.: Braconidae)

The objective of the current research was to evaluate the effect of the entomopathogenic fungus, Beauveria bassiana (Ascomycota, Hypocreales), on foraging behaviour of the parasitoid wasp, Aphidius matricariae Haliday (Hym.: Braconidae), on whole eggplant under microcosm conditions. A Y-tube olfactometer experiment showed the presence of the fungus caused avoidance of the parasitoid and conversely, its attraction towards the empty arm. Although most of A. matricariae significantly moved towards clean air (control), but a few were attracted to damaged eggplants infested with the sporulating aphid cadavers. Moreover, no-choice test for the effect of sporulating aphid cadaver on foraging behaviour of the A. matricariae revealed that the presence of the fungus significantly reduced the number of ovipositional attempts. In choice test, the parasitoid spent more time on damaged plants than on intact ones. The presence or absence of the fungus had no impact on allocation time of the parasitoid in an aphid colony. The results indicated that the parasitoid wasp, A. matricariae, was able to distinguish the entomopathogenic fungus and avoided entering the infected aphid colony. Nevertheless, when the parasitoid entered to an infected colony, it avoided contacting with the fungus or ovipositing. The results indicated thatthe released chemical cues of eggplant and also those of the entomopathogenic fungus, B. bassiana isolate EUT116, play an important role in the foraging decision making and also for increasing itsfitnessto control the green peach aphid.