Causes and Control Methods of Deformed Oyster Mushrooms

Deformed mushrooms are a relatively common physiological disorder in oyster mushroom production, severely affecting the yield and quality of oyster mushrooms, and even causing them to completely lose their commercial value. This disorder is mainly caused by improper management, and in a few cases by strain degeneration, mutation, or viral infection.

The main types of deformed mushrooms are:

1. Tall-stemmed mushroom: the cap is small, differentiation is poor, and the stem is relatively long. The cause is that during the primordium formation and differentiation stage, the mushroom house is short of oxygen, light is insufficient, and the temperature is relatively high, which affects the normal differentiation and development of the cap. Control methods: strengthen ventilation, adjust light and temperature.

2. Tumor-capped mushroom: the cap shows mainly many granular protrusions at the edge, light in color, the cap is stiff, and growth is slow; in severe cases, the cap differentiates poorly and is irregular in shape. The cause is that the temperature during mushroom development is too low and lasts for a relatively long time, causing disordered growth of the inner and outer cell layers. Control methods: adjust the mushroom house temperature to above the minimum temperature limit for oyster mushroom growth, and maintain a certain temperature difference to promote mushroom growth, development, and differentiation.

3. Cauliflower mushroom: the mushroom body resembles a cauliflower, with many branches; in the early stage the primordium is egg-shaped, swells, bulges, and does not differentiate. In the later stage it has many branches. The cause is that before or during fruiting, a high-concentration pesticide was sprayed on the mushroom bed or in the mushroom house, especially "dichlorvos"; young mushrooms are extremely sensitive and most likely to develop this disorder. It may also be that the mushroom house contains other harmful gases, such as excessively high carbon dioxide concentration or sulfur dioxide released from coal burning. Control methods: use pesticides cautiously in the mushroom house, and do not use them at excessively high concentrations. Especially during the fruiting period, dichlorvos must absolutely not be used; strengthen ventilation and air exchange to discharge harmful gases.

4. Shriveled mushroom: the mushroom body is normal in the early stage, but during the expansion stage it turns yellow, becomes water-soaked or shrinks, stops growing, and finally softens and rots. The water-soaked form is caused by excessive humidity or a relatively large amount of water sprayed directly on young mushroom bodies, causing the mushroom tissue to absorb water, which affects respiration and metabolism, so growth stops and the mushroom dies. The shriveled form is because the relative air humidity is relatively low and ventilation is too strong, with wind blowing directly on the mushroom bodies, causing the oyster mushrooms to lose water and die. Alternatively, the substrate nutrition is imbalanced; after a large number of primordia form, some grow rapidly, while the rest stagnate due to insufficient nutrient supply. Control measures: keep humidity between 80 and 85%, do not spray water on young mushroom bodies, and do not let wind blow directly on the mushroom bodies. Rationally balance the composition of the culture material. A small number of shriveled mushrooms are caused by strain degeneration, with symptoms that the cap curls back, turns yellow, and shrivels before it has grown large enough. Control methods: select excellent varieties.

5. Coral mushroom: the primordium differentiates abnormally, is loose, has many fine branches, and is shaped like coral. The cause is that when the primordium forms, ventilation is severely poor, light is extremely weak, and the nitrogen source is lacking. Control: strengthen ventilation and light regulation, adjust the carbon-to-nitrogen ratio, and add a nitrogen source.