Main Problems and Cause Analysis in Pleurotus pulmonarius Cultivation
At present, the cultivation area of Pleurotus pulmonarius in our city has exceeded 50 million bags, making it one of the main edible mushroom varieties cultivated in our city, with good cultivation prospects and benefits. Pleurotus pulmonarius cultivation can be carried out year-round through low-temperature treatment in cold storage. However, due to improper season, variety, culture medium, temperature treatment and water control, phenomena such as failure to fruit or death of mushroom buds often occur. Through years of cultivation practice, we have explored and summarized the above problems for the reference of peers.
1 Variety selection Currently, the main variety cultivated in our city is the Pleurotus pulmonarius series introduced from Taiwan, China by Luoyuan, such as Xiu 57, Pleurotus pulmonarius No. 1, No. 2, No. 3, etc. Their cultivation characteristics and product quality differ to a certain extent, and growers should introduce suitable varieties according to market demand. Generally, it is best to choose varieties suitable for cold storage treatment for fruiting, with many solitary mushrooms, fast flushing and good quality. It has currently been found that some varieties degrade after being introduced for many years, manifesting as delayed fruiting period, uneven fruiting after low-temperature treatment, or even no fruiting. Therefore, after introduction, small-scale trial planting must be carried out; otherwise, problems such as products being unsalable or even no fruiting are very likely to occur.
2 Cultivation season Generally, natural climate is used. Bag making for Pleurotus pulmonarius is best arranged in February to March or September to October. In these two production seasons, temperature is easier to control, humidity is not high, and the success rate of bag making is relatively high. Bag making in February to March requires attention to heat preservation, while bag making in September to October requires attention to cooling; at the same time, when bags are made in these two production seasons, the fruiting period can also coincide with the suitable season for Pleurotus pulmonarius cultivation. Since Pleurotus pulmonarius is mainly harvested as small mushrooms, the fruiting body growth stage of each flush is very short, nutrient consumption is relatively small, and the number of flushes is relatively large, while the entire cultivation cycle is rather long, reaching 6 to 10 months. For large-scale cultivation, 1 to 2 bag-making production seasons per year are sufficient. However, in factory cultivation, with complete facility conditions, such as temperature-controlled mushroom houses and cold storage facilities at the cultivation site, year-round production is possible. Otherwise, the fruiting period should avoid high summer temperatures. Otherwise, continuous high temperatures, with air temperature above 28°C, can very easily cause no fruiting.
3 Culture medium formula The medium generally maintains a certain carbon-to-nitrogen ratio (20:1 to 30:1), which can prevent mycelial overgrowth, advance the fruiting period, and in a suitable medium the later-stage bags are not easily shrunk and not easily form side mushrooms. It is best to add an appropriate amount of cottonseed hulls to the medium. The following formulas are for reference: ① Mixed broadleaf sawdust 77%, bran 20%, gypsum 1%, calcium carbonate 1%, sugar 1%; ② Cottonseed hulls 78%, bran 20%, lime powder 1%, sugar 1%; ③ Cottonseed hulls 39%, sawdust 39%, bran 20%, sugar 1%, lime 1%.
4 Main problems occurring in cultivation
4.1 Dead mushrooms
4.1.1 Symptoms In the early stage, fruiting bodies are numerous and dense, then wither and yellow until death, or a few remain or all die.
4.1.2 Causes and prevention ① Moisture: a. The medium lacks water, and water supply cannot keep up. b. Air relative humidity is insufficient, and the mushroom bodies lose water. c. Water accumulates on the surface of mycelia or mushrooms. d. Ventilation causes water loss too quickly. e. Spraying water too forcefully loosens the primordia. Preventive measures: Before bag making, the moisture content of the medium should be adjusted to 60% to 65%; during the fruiting period, the air relative humidity should be adjusted to 90% to 95%; spraying water should be light, with fine mist and multiple times, to prevent water accumulation on the bag surface and loosening of primordia; during ventilation in the fruiting period, care should be taken to prevent hot wind or cold wind from blowing directly on mushroom buds for a long time; when primordia have just formed, try not to spray water. ② Temperature: a. Temperature changes too greatly, causing nutrient backflow and leading to dead mushrooms. Preventive measures: After small mushrooms have formed, there should not be excessive temperature difference changes. Attention should be paid to excessive temperature changes caused by excessive ventilation. b. Continuous high temperature and stuffiness. Without a certain temperature difference, dead mushrooms or no fruiting occur. Normally, with continuous high temperature above 28°C, it is difficult to fruit without low-temperature treatment. Preventive measures: Bags must be subjected to low-temperature treatment, and at the same time the temperature difference should be increased, generally 10 to 15°C; attention should also be paid to ventilation and cooling of the mushroom house, and generally it should not remain above 28°C. ③ Oxygen deficiency: Insufficient ventilation causes oxygen deficiency; mushroom houses of different sizes easily cause uneven ventilation, forming local oxygen deficiency; too high planting density can also cause poor ventilation, and excessively high carbon dioxide concentration easily forms long-stemmed mushrooms or dead mushrooms; poor ventilation also easily causes dead mushrooms to mold, thereby affecting normal mushroom growth, or even causing dead mushrooms. Preventive measures: A single mushroom house is preferably 100 sq m; wall-type cultivation stacks should not be too high, generally not exceeding 2 m; each layer of bags should be separated by two bamboo strips, and the bag openings of each layer should be placed in a staggered manner. ④ Nutrition: Later-stage bags lack nutrition. This easily causes early opening of caps, forming thin mushrooms, or even dead mushrooms. Preventive measures: Add a little more cottonseed hulls and bran to the medium to enhance staying power. ⑤ Contamination: The surface layer of bags is contaminated by miscellaneous bacteria, mainly because dead mushrooms are not handled or due to water accumulation. This causes no mushroom growth or dead mushrooms. Preventive measures: Dead mushrooms should be handled immediately, and scratching should be done immediately; after bags are soaked in water, the water should be poured out cleanly.
4.2 Uneven fruiting
4.2.1 Symptoms Some bags in the same batch grow mushrooms while others do not, or after the same batch is soaked in water and stimulated by temperature difference, growth performance is inconsistent.
4.2.2 Causes and preventive measures ① The mycelial skin is too thick, affecting primordium formation: this may be because during the post-harvest mycelial recovery period the humidity is too high and ventilation is also good, causing mycelia to grow vigorously and form a mycelial skin. Or the C:N ratio of the cultivation substrate is imbalanced. Preventive measures: The skin can be removed or scratched (this may extend the fruiting period by nearly 1 flush); or later holes can be made or bags cut for fruiting. During the mycelial recovery period, try not to spray water. However, the surface layer of the bags should not be allowed to become too dry; otherwise, mycelial vigor will be reduced, affecting the amount of primordium formation. The bran content in the medium should generally not exceed 30%. ② Uneven water distribution: During soaking, water absorption is uneven, causing uneven fruiting. Preventive measures: When making bags, holes should be made in the middle as much as possible, so that water absorption can be faster and more uniform. ③ Uneven nutrient distribution: Mixing the material for an insufficient time causes uneven nutrient distribution, leading to uneven fruiting. Preventive measures: All medium components should be fresh, and the material should be mixed thoroughly. ④ Uneven temperature difference stimulation: Bags are stacked too tightly in cold storage, causing uneven treatment between the middle and edges; or the low-temperature treatment time is not long enough, causing uneven fruiting. Preventive measures: During low-temperature treatment, bags should not be stacked too tightly; the low-temperature treatment time can be appropriately extended.
4.3 Side mushrooms "Side mushrooms" appear at irregular points around the cultivation bag.
Cause: This is caused by the culture material not being pressed firmly, and gaps easily appear between the wall and the material, especially with soft culture material; after the mycelia reach physiological maturity, larger gaps also appear after cooling, and at this time the oxygen supply conditions are also relatively good. Under the induction of low temperature and light conditions, side mushrooms easily appear; or in the later stage of cultivation the bags soften and side mushrooms appear.
Preventive measures: Fill the material firmly, and mix the material evenly; add an appropriate amount of cottonseed hulls; choose mushroom bags that are not easily deformed.
4.4 Clustered mushrooms and solitary mushrooms When fruiting is induced by cutting openings, there are more clustered mushrooms; when fruiting is induced through openings, there are more solitary mushrooms; different varieties have different fruiting traits for solitary and clustered mushrooms; when the fruiting surface is flat, there are generally also more solitary mushrooms; high N content in the medium also easily forms clustered mushrooms. Generally, clustered mushrooms or solitary mushrooms can be controlled as needed.
4.5 No fruiting Pleurotus pulmonarius can be cultivated year-round using low-temperature treatment in cold storage. However, under natural seasons, there is generally no fruiting under high summer temperatures, and if the low-temperature treatment time is too short or the temperature difference is insufficient, fruiting is also difficult. Variety degradation also easily causes no fruiting. If bags are contaminated by bacteria, the manifestation is normal mycelial growth in the early stage, while in the later stage the bags become loose and soft and exude yellow water, causing no fruiting.
Preventive measures: Control the mushroom house temperature so it does not exceed 28°C; extend the low-temperature treatment time; choose suitable varieties; sterilize the bags thoroughly; inoculation must be carried out under sterile conditions.
4.6 Harvesting Harvest promptly, leave no mushroom stems, and immediately scratch the fruiting surface clean; no water should accumulate on the fruiting surface. Otherwise, mold contamination easily occurs.
Post-harvest management: Air-cool for 10 to 15 d to allow mycelial nutrients to accumulate again and vigor to recover. At the same time, during the mycelial recovery period, water should also be sprayed appropriately to prevent the surface mycelia from becoming too dry, which would affect vigor. Then soak in water - absorb water - low-temperature treatment (6 to 9°C, or temperature difference above 10 to 15°C, more than 24 h) - pour off water - move into the mushroom house for fruiting management - harvest again.