Watermelon-infesting Tephritidae fruit fly guild and parasitism by Psyttalia phaeostigma (Hymenoptera: Braconidae)

Abstract

AbstractAn ecological guild of Tephritidae fruit flies exploits cucurbit vegetable fruits, tremendously reducing their production worldwide. Knowledge of the composition of the guild of infesting flies in the field and information on their natural enemy species, might improve pest management strategies. Our aim was therefore to identify Tephritidae species infesting the watermelonCitrullus lanatus(Thunb.) Matsum. & Nakai in the Republic of Benin. Morphological and molecular identification of parasitoid species present in the field collections was also done. Infested watermelons were sampled in one of the main watermelon-production areas in the country. Adult tephritid flies emerging from watermelons were identified asDacus bivittatus(Bigot), D. ciliatusLoew, D. punctatifronsKarsch,D. vertebratusBezzi, Zeugodacus cucurbitae(Coquillet), andCeratitis cosyra(Walker). In this study period,D. vertebratuswas consistently the most abundant species emerging from watermelon.Dacus ciliatuswas the second most common species followed byZ. cucurbitae.The number of emerging fruit flies per kilogram of watermelon varied with collection date and month, and was most variable forD. vertebratus. Parasitism in the fruit flies was 1.6 ± 6.4% and occurred through one wasp species that was identified asPsyttalia phaeostigmaWilkinson (Hymenoptera: Braconidae). This solitary parasitoid is closely related to other members of theP. concolorspecies complex, some of which are used in biological control. Problems associated with identifyingPsyttaliaspecies and possibility of using this wasp as a biological control agent against tephritid flies were discussed.