Symptom Identification and Control Methods for Truffle Disease in Oyster Mushrooms

Oyster mushroom (scientific name: Pleurotus ostreatus; also known as oyster cap, rough-skinned oyster mushroom, oyster mushroom, black peony mushroom, and called Xiuzhen mushroom in Taiwan, China) is a species in the family Pleurotaceae, order Agaricales, phylum Basidiomycota, and is a quite common gray edible mushroom. The germ tubes of the oyster mushroom continuously branch and elongate, forming monokaryotic hyphae. After monokaryotic hyphae of different sexes combine (plasmogamy), they form dikaryotic hyphae. The dikaryotic hyphae have clamp connections on their septa. By means of these clamp connections, the dikaryotic hyphae continuously undergo cell division, produce branches, and grow and reproduce indefinitely under suitable environmental conditions.

In the hymenium, the tips of the dikaryotic hyphae produce basidia, whose genetic material recombines and segregates, forming four basidiospores. After the spores mature, they are ejected from the gills, completing a life cycle. Because there are many cultivated varieties of oyster mushroom, producers need to be able to simply distinguish the common varieties by appearance, so as to avoid a mismatch between production and market demand. Therefore, this article also mainly gives a brief introduction, from the perspective of appearance, to the morphological characteristics of several common cultivated varieties of oyster mushroom.

Nutritional analysis of oyster mushroom

1. Oyster mushroom contains substances such as selenium and polysaccharides that act against tumor cells, has a strong inhibitory effect on tumor cells, and also has immune properties;

2. The various vitamins and minerals contained in oyster mushroom can improve human metabolism, strengthen the body, and regulate autonomic nerve function, so it can be used as a nutritional product for weak patients. It also has a certain effect on lowering blood cholesterol and preventing and treating urethral stones, and can play a regulating role in menopausal syndrome in women.

Efficacy and effects of oyster mushroom

In terms of efficacy and effects, oyster mushroom is neutral in nature and sweet in taste, has the effects of tonifying deficiency and fighting cancer, can improve human metabolism, strengthen the body, and regulate the autonomic nerves. Oyster mushroom contains polysaccharides, has a strong inhibitory effect on tumor cells, and also has immune properties. Oyster mushroom also has the effects of dispelling wind and cold and relaxing muscles and activating collaterals, and can treat symptoms such as waist and leg pain, numbness of hands and feet, and discomfort of the meridians. In addition, oyster mushroom has therapeutic effects on hepatitis, chronic gastritis, gastric and duodenal ulcers, osteomalacia, and hypertension, also has a certain effect on lowering blood cholesterol and preventing and treating urethral stones, and can play a regulating role in menopausal syndrome in women.

Occurrence symptoms and control of truffle disease in oyster mushroom

Disease symptoms of truffle disease in oyster mushroom:

The hyphae of this fungus resemble those of the oyster mushroom and cannot be distinguished with the naked eye; it can penetrate deep into the substrate, competing with oyster mushroom hyphae for nutrients, water, and space from below upward, inhibiting the mushroom-producing ability of the oyster mushroom. Its physiologically mature mycelium forms ascocarps on the mushroom-producing surface of the substrate, especially in bed cultivation where it occurs over large areas in the region around the mushroom columns that contacts the soil; the ascocarps, growing in groups or clusters, have a brain-like wrinkled block shape, very much like walnut kernels with the astringent skin removed, wrinkled and not smooth; when they first appear, most mushroom growers mistake them for oyster mushroom pinning, but after several days there is still no differentiation, only the ascocarps change from an initial milky white to light milky yellow, then gradually to yellowish brown to red, and their volume also keeps expanding. At this point, it is too late to take various control measures. When this disease occurs severely, it can cause an entire batch of cultivation to produce no mushrooms at all. A high concentration of bleaching powder odor in the mushroom shed is one of the important signs of truffle disease occurrence.

Causes of truffle disease in oyster mushroom:

Pseudogymnoascus is a malignant contaminant in edible mushroom cultivation and production. Its spores exist in large quantities in the substrate and have extremely strong vitality. At a temperature of 16-35°C and an air humidity above 70%, they can germinate quickly and cause damage. This pathogen is especially serious for oyster mushrooms cultivated with casing soil.

Control measures for truffle disease in oyster mushroom:

1. The substrate must undergo sufficient and uniform heap fermentation treatment, and the moisture content must not be higher than 63%.

2. For the treatment of the cultivation soil, refer to the above.

3. Before the mushroom bags enter the shed, in addition to treating the greenhouse as required above, spray again 1-2 times with a bleaching powder solution at a concentration of 1.2% or more at an interval of 5 days. In areas with a record of disease occurrence, also add one spraying of a poly-methyl solution.

4. Once truffle disease is found to occur, immediately increase ventilation in the greenhouse, lower the temperature and humidity, and dig out the diseased area and its outer edge of 3 cm (the depth depends on the time and degree of occurrence) together with the soil and substrate, backfill with treated fine soil, and spray the entire shed carpet-style with a 1% bleaching powder solution, and apply a 400-fold 50% carbendazim wettable powder solution to the dug-out diseased areas.