The Pennsylvania Department of Agriculture announced an updated quarantine order on mushroom farms in Southeast Pennsylvania, expanding efforts and increasing funding to control the destructive pest Phorid fly, according to a statement from Agriculture Secretary Russell Redding. The Shapiro Administration has allocated $1 million in state funds through the Chester County Conservation District to support farmers in meeting new requirements aimed at controlling the pest.
Phorid flies, which do not harm humans or affect the quality of mushrooms sold in the marketplace, have caused crop losses and created nuisances for nearby homeowners. The revised quarantine order, effective March 23, 2026, requires all mushroom growers in Chester County to steam-treat mushroom houses and growing mediums between crops. This method is intended to kill adult flies, larvae, bacteria, fungus, and pathogens. Growers must also keep records of treatments and insect counts and implement one of five additional approved treatments: exclusion and inclusion methods, parasitic nematodes, predatory mites, adulticides (insecticides targeting adult flies), or long-lasting insecticide nets.
Secretary Redding said: “The department worked with mushroom industry leaders and Penn State researchers to develop safe, effective ways to control this pest, and demonstrated their effectiveness over the past year. We know these methods are safe and effective, but they only work when every grower is following the best management practices every day. By giving mushroom farmers tools to control pests and financial support to help them do it, the Shapiro Administration is showing that we are committed to helping farmers protect their valuable crops so they can continue to produce top quality products to feed Pennsylvania’s economy.”
State Representative Christina Sappey said: “I am very grateful for the expanded quarantine order and Best Management Practices. The increased resources the department is deploying to combat the phorid fly issue in our county demonstrate the high level of commitment necessary to support not only our residents but our mushroom growers challenged by lower yields who are in need of resources to employ best practices. I’m also pleased with the accountability measures included in the order. I believe this action and the continued research being done by Penn State will deliver positive results for our southern Chester County communities.” State Representative John Lawrence added: “Penn State brings some of the top specialists — not just in the nation but in the world — to the conversation. As it relates to specialty agriculture in general and mushrooms in particular, they are putting significant resources and research into this. PDA and Penn State are leading together with an all-hands-on-deck response to a major quality of life issue and a very difficult issue to resolve.”
Troy Ott from Penn State University said: “Researchers and extension professionals in the College and Agricultural Sciences at Penn State are working closely with growers on research to determine the best combinations of techniques called integrated pest management, to reduce fly numbers. Growers need science-based guidance to ensure that techniques implemented will be effective. Our extension professionals are working to ensure that the most up-to-date guidance on phorid fly controls is available to producers in both English and Spanish. We are so grateful for the support of PDA and the Pennsylvania legislature for funding our work through the Land Script line in the state budget.”
Pennsylvania leads U.S. Agaricus mushroom sales; Chester County hosts about 2,000 mushroom houses producing 69% of mushrooms sold nationally during 2024-25 with an estimated crop value of $1 billion as reported by Penn State University. Pennsylvania agriculture contributes $132.5 billion annuallyto the state economy and sustains over 593,000 jobs,according to the official website. The Department supports community prosperity by conserving farmland, involves more than 49,000 farm families managing over 7.3 million acres, aims to foster a robust economy while protecting public health, extends operations across the commonwealth,and offers inspection services for consumer protection while promoting state agricultural products.
More information about grant applications for financial assistance can be found through contacting Chester County Conservation District at 610-455-1381 or as listed on the official roster page.
