Harm and Control Methods of the Mold Mite in Edible Fungi

Tyrophagus putrescentiae belongs to the family Acaridae, genus Tyrophagus, and is distributed throughout the country.

(1) Harm characteristics

This mite is one of the most important pest mites of edible fungi. It frequently occurs in mushroom spawn bottles, mushroom beds, and shiitake mushroom blocks, and also damages straw mushrooms and oyster mushrooms. It also commonly occurs in large numbers in edible fungus cultivation materials such as rice straw, cottonseed hulls, and barnyard manure, especially in humid environments, where it reproduces quickly and occurs in large numbers. After the edible fungus mycelium is fed upon, it breaks apart and gradually tends toward aging and decline. After the fruiting bodies are damaged, brown depressions form, seriously affecting yield and quality.

(2) Occurrence pattern

The entire life cycle of Tyrophagus putrescentiae has four stages: egg, larva, nymph, and adult. Both the larval and nymphal stages have an active period and a resting period. The suitable temperature for reproduction of Tyrophagus putrescentiae is 24-25°C; the low-temperature limit for growth and development is 7-10°C, and the high-temperature limit is 35-37°C. Under suitable conditions, one generation takes about 15 days. At 23°C, 24°C, and 28°C, the egg duration is 5 days, 4 days, and 3 days, respectively. After hatching, the larva begins to crawl slowly, seeking a feeding site. At 22-27°C, the active larval period lasts 2-3 days, and the resting larval period lasts 0.7-1 day. After molting, the resting larva enters the nymphal stage. At 24-28°C, the nymphal period lasts about 5 days. Finally, it develops into an adult. Each female adult can lay 8 eggs in one day, with a maximum of 14 eggs. After egg laying is completed, the adult dies.

Tyrophagus putrescentiae has wide adaptability to temperature and a broad feeding range; therefore, wherever environmental conditions are suitable for the growth of edible fungi, there is a possibility of Tyrophagus putrescentiae occurrence. Tyrophagus putrescentiae prefers humid places rich in humus. If the sown spawn is unhealthy and mycelial growth is poor; if the moisture of the culture material is too high or the ratio is improper, so that the mycelium cannot grow well on the mushroom bed; or if cultivation management is inappropriate, causing the culture material to deteriorate, then severe occurrence of Tyrophagus putrescentiae is possible. Tyrophagus putrescentiae is a pest mite with very omnivorous feeding habits. It can feed on the mycelium and fruiting bodies of many edible fungi such as mushrooms, oyster mushrooms, and straw mushrooms, and can also feed on various stored grains and stored foods with high fat and protein content, as well as various sweet foods. Therefore, it can be said that the sources of mites are extremely widespread. In addition, discarding edible fungus waste and residual spoiled mushroom bodies around the mushroom house, or having the cultivation mushroom house close to warehouse grain piles, makes it prone to infestation by Tyrophagus putrescentiae.