Causes of Mushroom Death in Straw Mushroom Cultivation and Preventive Measures

Straw mushroom, also known as orchid mushroom or boot-foot mushroom, originated in Nanhua Temple in Shaoguan, Guangdong. China began artificial cultivation 300 years ago, and in about the 1930s of this century it was introduced to countries around the world by overseas Chinese. It is an important tropical and subtropical mushroom and the third largest cultivated edible fungus in the world. China's straw mushroom output ranks first in the world, mainly distributed in South China. Straw mushroom is rich in nutrition and delicious in taste. Every 100 g of fresh mushroom contains 207.7 mg vitamin C, 2.6 g sugar, 2.68 g crude protein, 2.24 g fat, and 0.91 g ash. Straw mushroom protein contains 18 amino acids, of which essential amino acids account for 40.47-44.47%. In addition, it also contains various mineral elements such as phosphorus, potassium, and calcium.

Environmental requirements of straw mushroom

Temperature: Straw mushroom is a high-temperature fungus, with a growth and development temperature of 10-44°C. Its temperature requirements vary by variety and growth and development stage. Basidiospores: the germination temperature is 30-40°C, with the highest germination rate at 40°C, followed by 35°C, and the lowest germination rate below 30°C; they do not germinate above 45°C or below 25°C. Mycelial growth: it can grow at 10-44°C, but growth is slow below 20°C, extremely slight at 15°C, almost stops at 10°C, and mycelia die below 5°C or above 45°C. Fruiting body development: the fruiting body development temperature is 24-33°C, with 28-32°C being most suitable; below 20°C or above 35°C, fruiting bodies are difficult to form.

Moisture: Straw mushroom is suitable for growing under relatively high humidity conditions. The moisture content of the substrate should be about 70%, and the relative air humidity should be 90-95%. When air humidity is below 80%, fruiting bodies grow slowly and have a rough, lusterless surface; when it is above 96%, the mushrooms are prone to necrosis and disease.

Light: During the vegetative growth stage, straw mushroom has no strict light requirements and can grow normally under dark conditions. When it enters the reproductive growth stage, light induction is needed to produce fruiting bodies. However, strong light should be avoided, and suitable light is 50-100 lx. The color of the fruiting body is related to light intensity: under strong light, straw mushrooms are dark black with luster; under weak light, the color is duller, even white.

Nutrients: Studies show that glucose, fructose, sucrose, peptone, asparagine, and glutamine are all good carbon and nitrogen sources for straw mushroom. Rice straw, waste cotton, and bagasse are the main materials for cultivating straw mushroom. Analysis shows that waste cotton is relatively rich in asparagine and glutamine, and the two account for 1/3 of its total amino acids. It can be seen that waste cotton is an ideal material for cultivating straw mushroom. However, the nitrogen content of waste cotton varies, between 0.25-1.45%, while the nitrogen content of straw mushroom substrate is suitable at 0.6-1%. Supplementing soybean powder can increase yield.

pH: Straw mushroom requires a pH between 4-10.3. The basidiospore germination rate is highest at pH 7.5. During the mycelial and fruiting body stages, pH 4.7-6.5 and 8 are suitable.

Causes of death in straw mushroom cultivation and preventive measures

During straw mushroom production, patches of small mushrooms are often seen wilting and dying, causing economic losses. The causes of mushroom death and preventive measures are summarized below.

1. Poor ventilation

Straw mushroom is a high-temperature aerobic fungus, and its growth and development process requires sufficient oxygen. During cultivation, in order to increase pile temperature, the film is sometimes covered for too long, causing excessive carbon dioxide in the pile and leading to oxygen deficiency. Small mushrooms wilt because of poor ventilation and poor gas exchange, making it difficult for them to grow normally. Within 1-4 days after sowing, note to ventilate for half an hour every day. As the amount of mycelium increases and pinhead mushrooms appear, appropriately increase ventilation.

2. Lack of moisture

Straw mushroom growth requires a large amount of water. If there is insufficient water when building the pile and sowing, or if water is not replenished in time after harvesting mushrooms; if the straw covering is too thin and has poor moisture retention, all of these can cause small mushrooms to wilt. After sowing, before the mycelium fully grows and forms pinhead mushrooms, if moisture is felt to be insufficient, a heavy watering can be given once. After the first flush of mushrooms ends, replenish water sufficiently. On sunny days, spray water on the straw covering to prevent water in the substrate from evaporating.

3. Sudden temperature changes

Straw mushroom mycelial growth and fruiting body development have different temperature requirements. Generally, the mushroom-forming temperature is about 30°C. However, continuous high temperatures in midsummer can cause small mushrooms to die in batches. Therefore, in the intense summer heat, choose a shady site for pile cultivation, cover the substrate with a straw covering and spray more water, and build a shade shed above the pile.

4. Acidic environment

Straw mushroom mycelium is suitable for growing in an alkaline environment. When the pH is below 6, although buds can form, they are difficult to grow into mushrooms. After harvesting the first flush of mushrooms, spray 1% lime water or 5% plant ash water to keep the pH of the pile at about pH 8. 5. Unsuitable water temperature

Straw mushroom has certain requirements for water temperature. If well water at about 20°C is sprayed, or surface water heated to above 40°C by direct sunlight is sprayed, all the small mushrooms will wilt and die by the next day. Watering should be done in the morning and evening, and the water temperature should preferably be about 30°C.

6. Contamination by miscellaneous fungi and pest infestation

Using moldy rice straw and other raw materials as substrate, or cultivating in an unclean site, will lead to a large outbreak of pests. Especially when cultivating straw mushroom with cottonseed hulls, after mites appear, the mycelium in the substrate will quickly disappear, causing all young mushrooms on the bed surface to die. Adding 3% tea seed cake powder or 0.2% trichlorfon solution into the mushroom pile can achieve a pest control effect. Straw mushroom is very sensitive to pesticides. When mushroom buds appear, pesticides must not be used.