Predatory behavior of long-legged flies (Diptera: Dolichopodidae) and their potential negative effects on the parasitoid biological control agent of the Asian citrus psyllid (Hemiptera: Liviidae)

Abstract

Summary Apparently because of mulch buildup and abstinence from pesticide use, an organically managed citrus grove in Vero Beach, Florida, can support large populations of long-legged flies (Diptera: Dolichopodidae) that impose predation pressure on inundative releases of Tamarixia radiata (Waterston) (Hymenoptera: Eulophidae) parasitoid wasps to control the Asian citrus psyllid (Hemiptera: Liviidae). During peak activity, flies on wing characteristically hawk wasps in mid-air as the wasps are sprinkled from shipment containers onto the leaves of citrus plants. Flies on leaves enter into entrained scramble competition for prey by systematically "canvassing" upper leaf surfaces in rapid, jerked movements and, albeit infrequently, attack and eat wasps when encountered during this behavior.