New Garden Residents Band Together in Attempt to Eradicate Mushroom Flies

By Chris Barber, Daily Local News

POSTED: 06/18/17, 9:52 PM EDT | UPDATED: ON 06/18/2017

NEW GARDEN >> Residents of several housing developments in the southern part of the township are conducting their own scientific research on the pesky flies that have invaded their homes for about three years.

The tiny flies, called phorids, have become pests in many local mushroom farms as well as some nearby neighborhoods. Last year state Sen. Andy Dinniman, D-19, of West Whiteland called the residents together get information and try to work out solutions. On Thursday, he held the third of these meetings at the New Garden township municipal building and presented updates on actions that had been taken and data that had been obtained. He also got some updates himself, as residents presented information they have found through their own investigations.

Barbara Rundle, who has become a popular spokesman for the people living in Harrogate — a mature adult community near Hockessin, Delaware — also has undertaken to study the flies intensely from the time they first invaded the area.

Historically, the flies first came to homes several years ago in such volume that they covered the walls and ceilings, even piling up in bathrooms toilet tanks and crawling around on their Thanksgiving dinners. They also seem to like living in mulch, they are attracted to light and they appear to have a life span of about 17 days.

Since the beginning, Rundle has trapped them on sticky paper, counted them, experimented with insecticides, determined the demographics of the infestations with maps and kept in touch with neighbors to determine the quality of their infestations.

Lately she has made a new discovery:

“I found them coming out of the ground,” she said, adding that their colonies went down as far 6 feet into the earth. This was news to her neighbors and the environmental officials at the meeting, who had suggested that the flies bred in the mushroom houses and then went straight to the nearby houses.

But Rundle is not alone in her scientific quest. Other homeowner investigators who are likewise suffering the invasions and doing their own research including in Lower Oxford, Kennett Township and a new development in New Garden, Harlow Pointe. They are also counting, trapping and watching.

The information that the homeowners shared on Thursday is that the infestations are the worst in July, August and September, that the flies seem to like water, and that different homes have different degrees of infestation, but they don’t know why.

They expressed their impatience about the slow progress of finding the solutions and their frustration that some of the local mushroom companies seem not to be following practices that could kill the bugs off.

Also present at the meeting was state Rep. Eric Roe, R-158, of East Marlborough, He said he is also concerned about the phorids and fears they are becoming life issues and could become a health issue.

Probably the two most schooled scientists who spoke at the meeting were Eric Toedter of Kaolin Mushroom Farms, who has been studying them from the beginning and is head of the American Mushroom Institute Integrated Pest Management group; and Nina Jenkins, an entomologist from Pennsylvania State University whose studies are focusing on the phorid flies.

Jenkins said there has been a body of knowledge going back to the 1960s. They know that the phorids like to eat the mycelium (the facia-like root system of the mushrooms).

The scientists don’t know where the phorids go during the winter. They know that steaming off the mushroom houses after the cropping kills them in the house, but they are resilient little creatures. Scientists also don’t know how to keep them from traveling to places outside the mushroom houses.

Jenkins has currently been engaged in looking at 17 mushroom farms for 12 months, putting out sticky cards and correlating the populations with the growing cycles. She has even developed dusting substances of different colors that stick to the phorids and can show which of the bugs went where.

She said she considers it odd that the phorids would flee the mushroom houses and go to residential developments because the houses are not as “tasty” as the mushroom growing environment.

Jenkins also explained that even if an effective insecticide is developed, it takes some time for it to be grated permission to use or “a label.”

Toedter said he is as concerned as the homeowners, because the phorids are a big problem for the growers as well. He said he knows that steaming off the mushroom houses after the crop makes them clean for the next round, but they still arrive as the new crop spawn run occurs.

Dinniman said he was encouraged on three counts:

1. Research continues not only in labs but among homeowners

2. The American Mushroom Institute is developing and policing “best practices” to help ensure that the growers follow cleanliness standards.

3. He has obtained a $40,000 grant for continuation of the phorid study at Penn State.

When Dinniman was asked why the studies done by the Department of Environmental Protection have not been made available, he answered at some length that the Department, among others like the Department of Education, stubbornly fails to share information. “Government doesn’t work the way it should. Transparency doesn’t exist,” he said.