Hygiene programmes

The most important factor for successful control of pests and diseases on any mushroom production unit is strict hygiene. To be effective this requires meticulous attention to detail and good lighting in the production houses. The following thirteen practical measures should always be carried out, bearing in mind that the aim should always be to prevent the development of pest and disease problems, as effectively as this is possible.

The production house should be thoroughly cleaned between crops after all of the compost has been thoroughly removed. Wash down, preferably using a power washer, to remove dirt and debris. Extreme cleanliness is essential to eliminate disease organisms which would otherwise thrive in the warm, moist environment.

Sterilise the surfaces using a formalin-based disinfectant at a 2 percent concentration rate or one of the proprietary disinfectants, for example Environ, Sudol, Prophyl, Premisan etc at a 0.4 percent  concentration rate. The recirculation fan should be left running during fumigation so that spores in the ventilation system are killed. The temperature should be kept above 15°C and relative humidity above 50% to improve the fumigation efficacy. Experience suggests that formalin can be counterproductive in trying to avoid Trichoderma contamination as this fungus grows strongly on surfaces after they have been sterilised by formaldehyde alone.

Incoming and outgoing air should be filtered and these filters should be changed at the end of each crop.

Use clean foam mats soaked in disinfectant, or disinfectant foot baths placed at the entrance of each growing house. These mats should be cleaned weekly.

Protecting the casing from contamination is vital as foreign materials, such as soil, coming into contact with fresh casing is a major source of disease infection. Windborne dust from infected spent compost is an even greater source of disease infection than soil. Ensure that the area where the casing is to be unloaded is disinfected and sheltered. Prepared casing should be covered with clean polythene until it is required. Any equipment used for casing, for example buckets and trolleys, should be sterilised with a proprietary disinfectant.

Effective measures for the routine control of flies should be continually used taking particular care during the months May-October. In addition to the damage which fly larvae cause by eating mushroom mycelium or killing pins, the adults also carry diseases such as Verticillium, Mycogone and Cobweb.

Once the mushrooms have been picked all the broken stumps and fallen mushrooms should be removed from the beds as these are ideal areas for disease and pest development.

Mushroom stems and other waste should not be left to accumulate in the growing house. Daily disposal is vital, as bags of waste provide ideal breeding conditions for flies and mites. Extreme cleanliness is essential in the growing house to avoid the introduction of diseases which can thrive in the warm, moist environment.

The concrete outside the growing house should be washed down at least weekly with a proprietary disinfectant at the recommended rate.

Knives, trolleys, waste buckets and thermometers should be disinfected before moving them to other houses - the same applies to any other implements which are transferred from one house to another.

Always start working from the last house filled, and try as far as possible to pick from the newest to the oldest house.

Spent compost should be

Terminate diseased crops early - this will reduce the risk of an epidemic developing.

Use separate overalls for each house - spores can be carried on clothing.

When emptying a house, first water the bags to reduce dust and then load them onto a trailer with as little disturbance as possible.