Mushroom production
2. Pests and diseases
Department of Primary Industries and Fisheries.
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.
Diseases of mushrooms
Fungal diseases
Even though the mushroom itself is a fungus, it can in turn be affected by a range of fungal pathogens, listed below in Table 1.
Table 1. Fungal diseases of mushrooms
|
Disease |
Other names |
Symptoms |
|
Dactylium |
Cobweb, mildew |
White to pink cobweb-like fluffy mould. |
|
Diehlomyces |
Calves brains / false truffle |
A competing fungus which produces brain-shaped fruiting bodies. |
|
Fusarium |
Damping off |
Mushrooms wither. |
|
Mycogone |
Wet bubble / white mould |
Dense white growth on gills. |
|
Papulaspora |
Brown plaster mould |
Brown plaster-like patches on casing. |
|
Scopulariopsis |
White plaster mould |
White plaster-like patches on casing. |
|
Trichoderma |
Green mould |
Dark green mould patches on casing spreading to lesions on stems. |
|
Verticillium |
Dry bubble / brown spot |
Brown irregular pitted areas on stems and caps. Distortion and splitting. |
Bacterial diseases
Pseudomonas (bacterial spot, bacterial or pit or brown blotch), causes yellow to brown blotches on the cap which may exude sticky residues. Early symptoms are similar to verticilium.
Other diseases
A range of viral diseases attack mushrooms. Fruiting bodies that are either noticeably elongated or flattened, or gradually decreasing crops or flushes should be examined. If viral diseases are suspected, professional advice on eradication should be sought.
Management
Maintaining high levels of hygiene will assist any pest management program by reducing the number of problems that are likely to occur. If an outbreak does occur, ensure that the pest or disease is correctly identified before taking any action.
There are several chemicals registered for use on mushrooms in Queensland - contact your local chemical reseller or the Australian Mushroom Growers Association for details. Always read the label and follow the enclosed instructions carefully.
Further information
Other DPI&F Notes in the Mushroom Production series are:
Current national information on agricultural chemicals registered for use on mushrooms is available on the Infopest CD-ROM. Write to DPI&F, GPO Box 46, Brisbane, Qld. 4001, email infopest@dpi.qld.gov.au or phone (07) 3239 3967 for further information.
The Australian Mushroom Growers Association regulates the mushroom growing industry. They can be contacted at Locked Bag 3, 2 Forbes St, Windsor, NSW, 2756. Ph (02) 4577 6877 or Fax (02) 4577 5830.
Information contained in this publication is provided as general advice only. For application to specific circumstances, professional advice should be sought. The Department of Primary Industries and Fisheries, Queensland has taken all reasonable steps to ensure the information in this publication is accurate at the time of publication. Readers should ensure that they make appropriate inquiries to determine whether new information is available on the particular subject matter.
Last updated 04 February 2004
