Diachasmimorpha longicaudata Parasitism Response to Medfly Host Fruit and Fruit Infestation Age

Abstract

The parasitoid <i>Diachasmimorpha longicaudata</i> (Ashmead) (Hymenoptera: Braconidae) is increasingly being used in integrated pest management (IPM) programs as a biological control agent in order to suppress tephritid fruit flies of economic importance. Innate and acquired behavioral responses-such as pest host fruit preference-of parasitoids can modulate their efficiency in the field and should be taken into consideration prior to parasitoid species' selection for mass-rearing. We have assessed the influence of medfly-infested (two infestation ages, 1 and 4-d-old) and uninfested fruit species on host preference and efficiency of <i>D. longicaudata</i> by using a multistep assay including olfactory, laboratory and semi-field trials. We found that <i>D. longicaudata</i> was significantly more attracted to medfly-infested apples for both infestation ages, with the oldest being the most preferred. <i>D. longicaudata</i> exhibited a significant preference among the four fruits tested. The implications of these behavioral responses of <i>D. longicaudata</i> to medfly host fruits and infestation age are discussed in relationship to its use in IPM programs in the Mediterranean basin area.