Introduction of exotic parasitic wasps for the control of<i>Liriomyza trifolii</i>(Dipt., Agromyzidae) in Senegal

Abstract

Abstract Liriomyza trifolii Burgess had first been reported from Senegal in 1980. Field surveys in 1982 revealed its presence in all vegetable growing areas of the country, heaviest damage being registered in the Cap Vert. Five indigenous eulophids (larval parasitoids) plus five other rare parasitoids, frequently parasitized over 90% of the flies. These rates were higher in insecticide free fields, and very much above the 30–40% reported for 1981. The most important parasitoids were Hemiptarsensus semialbiclava (Girault), which dominated in the second half of the dry season, and two Chrysonotomyia spp., which were more abundant in the rainy season. Surveys for exotic parasitoids indicated Diaulinopsis callichroma Crawford from Trinidad to be a promising species for introduction in the New World. This parasitoid, together with eight other chalcidoids (mostly larval parasitoids) and two braconids (larval‐pupal parasitoids), were collected in the field or received from established insectary cultures. They were studied and shipped for rearing and release in Senegal. Nine species were released at the end of 1982 and in 1983. Many were recovered shortly after release, but only Opius dissitus Muesebeck was recovered in later samples and became relatively abundant.