This is the third short news article written by students, during the professional development class of Spring 2024, about each other's research.

Student Spotlight: Malachi Brought

By Kylie Green

How bad could one fly really be? An innocuous question with a complicated answer, as the mushroom phorid fly, Megaselia halterata, has caused hundreds of thousands of dollars in losses to mushroom farms each year due to reduced crop yield.

Mushroom phorid fly larvae feed on the root system of mushrooms, in turn reducing crop yield by damaging the mycelium. One female can yield over a trillion flies in 6 months. Mushroom farms are composed of between 15 and 90 growing rooms. Because the fly life cycle is between 18-24 days, the number of mushroom flies can increase exponentially within a very short time. Additionally, phorid flies have become residential pests in the areas surrounding mushroom farms as they are blown away from farms and into residents’ homes. Malachi Brought, an Entomology graduate student in Professor Michael Wolfin’s research group at Penn State, aims to develop cost-effective management practices for controlling the mushroom phorid fly using entomopathogenic nematodes.

“Currently, there is nothing available on the market for farmers to control fly larvae in the compost, which is where treatment should be focused to protect the actively growing mycelium” say Brought.

Mycelium is the root- like structure within the ground that transports nutrients to the mushrooms growing on top of the soil, and damaging these roots in turn prevents mushroom growth. However, major crop losses are due to the insects spreading mushroom disease on the farms, killing the mushrooms before they are harvested. Previously, a pesticide called diazinon had been used to control fly larvae in compost but was banned for use on the fungus by the Environmental Protection Agency in 2012 due to toxicity to humans and wildlife. To bypass this hurdle, Brought is focusing on using the entomopathogenic nematode, Steinernema carpocapsae, to control larvae in compost as it is already a biocontrol approved agent in the United States. S. carpocapsae is a parasite that infects larvae in the compost, in turn killing the larvae without damaging the mycelium or other beneficial organisms.

As S. carpocapse have been domesticated, different strains may have developed different behaviors based on production methods. While his prior work established that the species S. carpocapse will infect and kill mushroom phorid fly larvae, Brought is using a new strain and performing mortality and persistence assays to determine the most effective application methods. His persistence assays have already led to a change in application methods as he discovered that the nematodes can only live 4-5 days without a host. Instead of mixing the nematodes into the compost once, application should be done every 4-5 days while growing in a 50-day cycle.

While studying microscopic worms every day can be challenging, Brought is excited to make a substantial positive impact on farmers and residents alike. Brought’s research has just begun and will continue to focus on maximizing the efficacy of nematode application, as well as developing targeted applications for larvae in the compost parts they are most prevalent in to reduce cost of application.

Brought says “Biocontrol in indoor farming is really overlooked, and with the applied nature of the project, farmers could increase their yield and profits by reducing this pest”.

Malachi Brought is a MSc student in Professor Michael Wolfin’s research group in the Department of Entomology at Penn State and is funded by Pennsylvania Department of Agriculture.