Mushroom-Pests and diseases

Pests and diseases

Mushrooms are the edible fleshy fruiting bodies of certain fungi, which may be gathered wild or grown under cultivation. The most commonly cultivated mushroom species is Agaricus bisporus, although many other species are now gaining recognition in Australia due to the widespread consumption of Asian cuisine. This note describes the pests and diseases of Agaricus species.

Cultivated mushrooms are usually grown in the dark in climate-controlled rooms. The fungal innoculum or "spawn" is added to a pasteurised substrate in growing containers or beds. After the fungal strands (mycelia) have spread through the compost, a layer of peat or soil (the "casing") is added. The fruiting bodies begin appearing about 6 weeks after spawning and continue appearing in flushes about 7-10 days apart for the next 6-8 weeks. The first three flushes are the most productive. The cap and a small section of connected stem are usually harvested before the caps are fully expanded.

Pest management programs, particularly for diseases, are made more difficult by the fact that the mushroom is itself a fungus. Strict adherence to hygiene programs at all stages of production will greatly reduce potential problems.

Invertebrate pests

Arthropods

A variety of small fly and midge species are pests of mushrooms. The larvae feed on the fungal mycelium in the compost, but may also tunnel into the fruiting bodies.

A range of mite species may affect the mushroom crop. Some directly damage the fruiting bodies, some may attack the mycelium and some mites are predatory on other mites, fly eggs, nematodes or bacteria. Mite damage on the fruiting bodies often shows up as small cavities in the stem and cap similar in appearance to bacterial pit disease. Mycelium-eating mites can cause high yield losses. Mites are very small and easily transported on clothing and tools.

Springtails are commonly associated with compost, and can damage the crop if present in high enough numbers. Slaters and millipedes may also cause damage to the fruiting bodies.

Nematodes

Nematodes will cause a loss in yield and brown, watery mushrooms, and in extreme cases a soggy, smelly compost. Peat is a common source for nematodes and should be treated before use.

Mushroom-Pests and diseases