Cause A fungus, Trichoderma harzianum, that is common in soil and on organic matter. This fungus sporulates abundantly with sufficient light and the spores spread readily through the air or any mechanical means. Red pepper mites are often associated with this disease.
Symptoms Pale brown, irregular spots on mushroom caps. A white mold that turns green with sporulation may develop on wooden boxes, compost, and sometimes with the cut end of mushrooms.
- Disinfest all structures and equipment (including clothing) associated with spawning (use immediately after disinfestation or store where air is filtered).
- Filter air to prevent colonization of sterilized compost through spawning.
- Control red pepper mites.
- Mertect 340-F at a maximum of 5.4 fl oz/1000 sq ft of spawn grains or at 8 fl oz/1000 sq ft of casings or at 4 fl oz for all other timings; not to exceed a combined total 20 fl oz/1000 sq ft of product. Do not apply to gypsum, limestone. or chalk. Do not apply within 12 hours of harvest. 12-hr reentry.
- Trilogy at 0.5% to 2%. Not labeled for use in Oregon. 4-hr reentry. O
Reference Fletcher, J.T., White, P.F., and Gaze, R.H. Mushrooms: Pest and Disease Control. 1989. Intercept Limited, Andover, Hants, England. 174 pp.