Parasitism of Anastrepha fraterculus by Diachasmimorpha longicaudata in semi-field conditions

Abstract

Diachasmimorpha longicaudata is the most used braconid in biological control of fruit flies. The ability of host finding in different type of fruits is critical to parasitism efficiency. We evaluated the parasitism of D. longicaudata in semi-field conditions in order to assess the ability of this parasitoid in finding its host. Two cages (2 x 2 x 2 m), each containing 24 plants (up to 1.5 m each) of fruit trees simulated an orchard environment. In experimental orchards located in Porto Alegre region, RS, fruits of guabiroba, guava, yellow strawberry guava, persimmon, peach, loquat and kumquat were caged to avoid oviposition and natural parasitism and were artificially infested during 48 h with A. fraterculus. Nine days after, for each bioassay, eight infested fruits of a single fruit species were arranged individually on a Petri dish cover and placed at the base of the same fruit tree species. Four couples of D. longicaudata were released into each cage while the other cage served as a control treatment. After 24 h from parasitoid release, the fruits were removed and kept in containers until the emergence of parasitoids or fruit flies. We run three replications for each fruit species, replacing the parasitoid couples and infested fruits. All fruits tested were infested by A. fraterculus. The parasitism was tailed on all fruit species and ranged from 16% in guava to 47% in guabiroba. Thus, D. longicaudata can find its hosts in native and exotic fruits under the studied conditions.