IMAGE: Mike Wolfin The Penn State team knew that many chemical products would be effective in killing phorid fly larvae, but they cannot be used because they are not permitted by EPA for use in mushroom crops. “It was a complicated challenge because anything that you add to the compost may be taken up by the mushroom," said team co-leader Tom Baker, distinguished professor of entomology and chemical ecology. The team started screening products for potential use in the compost for larval control, but they did not find anything that was effective. The researchers then started looking at products for control of adults, as these could be targeted away from the compost/crop. They also studied the biology and behavior of the adults to determine if the flies were establishing populations in the residential areas. They found that populations were sustained only on the mushroom farms.