Irradiation of Melon Fly, Zeugodacus cucurbitae (Diptera: Tephritidae), in Artificially versus Naturally Infested Papayas

Abstract

Many fruits are naturally rarely infested by their quarantine pests or are poor hosts for larval development and may require manipulation during quarantine treatment development to achieve infestation. This study compared the effects of artificial versus natural infestation on melon fly, Zeugodacus cucurbitae (Cocquillet) (Diptera: Tephritdae), survival in papaya after irradiation. Papayas were infested either by inserting third instar larvae through a bore hole into the center of the papaya (artificial infestation) or by exposing fruit to adult oviposition in small cages and raising larvae to third instar (natural infestation). Infested fruit were then irradiated at 40 Gy and held for adult emergence. Mean adult emergence was higher in artificially (7.6%) than naturally (0.6%) infested papayas after irradiation, but the difference was non-significant. The advantages to artificially infesting fruit during quarantine treatment studies are discussed.