Frass Semiochemicals Important to Corn-Infesting Ulidiidae (Diptera)

Several similarly appearing species of silk fly (Diptera: Ulidiidae) are extremely destructive pests of sweet corn in southern Florida.   Currently, silk flies are managed solely with multiple broad spectrum insecticide applications, and there is concern that some species are developing resistance to these insecticides.  Studies were initiated to examine the chemical ecology of silk fly pests in the hopes that the information gained could lead to novel semiochemical-based management tactics.  Previously, a still air laboratory bioassay was developed that demonstrated flies were highly attracted to armyworm frass.  Volatiles from the frass were collected and tentatively identified using GC-MS.  Frass volatiles were then screened for physiological activity using electroantennography and assayed for attractiveness in the laboratory bioassay.  Several volatile components showed promise, warranting further evaluation in field tests.