Extension to hire phorid fly liaison for residents, researchers, mushroom farms

UNIVERSITY PARK, Pa. — In an effort to ease the predicament of southern Chester County neighborhoods besieged by mushroom phorid flies, Penn State Extension will hire an entomologist to serve as a liaison between residents, the researchers trying to solve the fly problems, and mushroom farmers.

Funded by a $90,000 grant from the Pennsylvania Department of Agriculture, the outreach will foster a closer relationship between residents suffering from invasions of mushroom phorid flies, Penn State Extension specialists, and research entomologists in the College of Agricultural Sciences, said Maria Gorgo-Gourovitch, horticulture extension educator in Chester and Berks counties.

"Extension understands the severity of the problem that frustrated residents face, and we are trying to help them as much as we can," she said. "We want to provide technical support and communication on phorid fly issues for residents by providing them with a resource person to focus on short-term measures that could be taken to improve their quality of life."

The initiative also will increase awareness of any new integrated-pest-management solutions that might be found for both mushroom farms and nearby residents. Gorgo-Gourovitch and the new liaison will offer innovative education and training programs focused on those solutions in English and Spanish to urban communities in affected areas.

Swarms of the tiny flies associated with mushroom production in two Chester County townships have plagued residents in rural developments in recent years, especially in late summer and fall. The phorid fly infestations — which also damage mushrooms, limit crop yields and make the job of picking mushrooms onerous — are showing up at other mushroom farms.

The mushroom phorid fly problem was triggered in 2012 when the U.S. Environmental Protection Agency ruled that diazinon — an insecticide mushroom growers had used successfully for decades to control the pest — could no longer be used in mushroom production because of its toxicity. Mushroom farmers now don't have a product they can use to control these flies.

The extension phorid fly liaison will regularly visit mushroom farms to take part in research and to communicate results to residents, according to Tom Baker, distinguished professor of entomology and chemical ecology. While the liaison will not serve as a pest-control agent going into homes applying pesticides, it is envisioned that he or she would help promote discussions and awareness among residents about any innovative techniques that have shown promise in helping to alleviate fly problems in homes.

"Everybody should understand that this is a complex problem both in the residential areas and within the mushroom houses, for the homeowners and the mushroom farmers," said Baker, co-leader of the research team tackling the problem with Senior Research Associate Nina Jenkins. "We are working hard, trying new techniques to solve the mushroom fly problem at its source — at the mushroom farms."

The nearest-term solution that the research team is exploring is reducing the seasonal buildup of flies within mushroom houses by eliminating the adults themselves. In addition, intensive research in Jenkins' lab has been targeting the fly eggs and larvae through trials of new, biopesticide materials that eventually can be used in the long term to kill these immature flies during mushroom production before they can become adults.

Baker said one new approach for adult fly control that researchers will test in the coming months is to eliminate large numbers of flies within mushroom-growing rooms by capturing them continually with the aid of screening in the air-circulation-return system.

"This is a fairly new idea, an offshoot of the 'eave tubes' concept developed by Penn State researchers to capture mosquitoes carrying malaria in Africa," he said. "We have to try things that don't involve toxic insecticides that are not permitted for use in mushroom production."

Creating the liaison position is not a substitute for continued research, Baker emphasized. Instead, it should be seen as a bridge to carry residents to a future when mushroom phorid flies can be suppressed at their source within the mushroom houses using new, noninsecticidal techniques that keep fly populations at sufficiently low levels so that surrounding neighborhoods do not experience problems.

"With this liaison, residents will have an empathetic ear to listen to their concerns and to help find ways in the near-term for residents to find relief from flies," he said.

Three life stages of the mushroom phorid fly are shown: from bottom, pupa, larva and adult. This species is an "obligate fungal feeder," meaning it cannot feed or survive on anything other than the thread-like fungal mycelium found in mushroom compost. The flies are not known to be a health hazard to humans or carry any human or animal disease-causing organisms, but the sheer numbers of them and their ability to infiltrate homes are severely stressing out some southern Chester County residents.   Credit: Penn StateCreative Commons

Last Updated June 07, 2018