Pests and Diseases

Adequate disease management, along with excellent hygiene, should be an integral part of any mushroom operation. On this page, find recommendations for managing mushroom pests and diseases. Access advice on identifying green mold, bacterial blotch disease, sciarid and phorid flies, nematodes, and verticillium dry bubble. Tips on integrated pest management for mushrooms and on the proper use of disinfectants can be found here, as well.

Common Mushroom Pests and Diseases

Mushrooms are susceptible to a number of pests and diseases that often affect crop quality and yield. Verticillium dry bubble is by far the most common fungal disease among commercially cultivated white button mushrooms. The most noticeable symptom is often a globe-like mass of mushroom tissue (a dry bubble). Verticillium management practices to incorporate include keeping the farm clean, avoiding overgrowth of the spawn, and using strains that are easy to pin.

Green mold is another prevalent disease among cultivated mushrooms. It is typically characterized by a dense layer of mycelium on the casing surface that changes from white to green color. Green mold can cause significant yield losses, especially in Agaricus, Pleurotus, and shiitake mushrooms.

Fly Infestations

Sciarid flies, as well as phorid flies, are a major concern in the mushroom industry. Female phorid flies are attracted to mushroom houses by the odor of growing mycelium (spawned compost). There, they lay eggs beneath the surface of the compost or in the casing. Phorids tend to feed on mycelium; however, the economic effect is not fully known.

Similarly, sciarid larvae are known for feeding on mycelium and destroying mushroom tissue. Adult sciarid flies do not feed on mushrooms but can carry pathogens such as mites, nematodes, and mold spores.

Phorid flies are more numerous than sciarids; however, they cause less damage to mushroom crops. Learn more about managing fly issues with Penn State Extension’s On-Farm Management of Phorid Fly Infestations.

Integrated Pest Management in Mushroom Production

Integrated Pest Management (IPM) practices can help producers prevent and reduce the spread of pests that lower mushroom production and quality. IPM exclusion techniques, for instance, prevent pests from entering new rooms, as well as escaping from old ones.

Mushroom growers, as well as researchers, can benefit from Penn State Extension’s PA Mushroom Integrated Pest Management Handbook. The publication covers both the theory and practical aspects of IPM in mushroom growing.

Disinfectants and Sanitizers Usage in Mushroom Production

Though often used interchangeably, disinfectants and sanitizers offer distinct benefits. Disinfectants are generally used to destroy, inhibit, or neutralize the growth of disease-carrying microorganisms. The most common disinfectant used in mushroom farms is in picking halls and breezeways (floors, walls, and doors). When deciding which disinfectants to use in the mushroom house, growers should consider its effectiveness and corrosiveness.

Sanitizers, on the other hand, are used to reduce – without necessarily eliminating – microorganisms to levels considered safe by health codes and regulations. Sanitizers are divided into food contact and non-food contact products.

In this section, Penn State Extension offers valuable resources on managing mushroom pests and implementing IPM best practices.