Analysis and Countermeasures of Meteorological Diseases of Pleurotus ostreatus

The cultivation practice of Pleurotus ostreatus for many years has proved that the abnormal sharp rise or sudden drop of temperature in spring can cause the same meteorological disease of Pleurotus ostreatus in the same climatic area. if it is poorly managed, a large number of wilting and death will occur in the fruiting body of Pleurotus ostreatus within 1-7 days. heavy losses. Therefore, it is of great practical significance to study the meteorological diseases of edible fungi, make use of the weather forecast results and formulate effective defense measures to reduce the loss of edible fungi and improve the economic benefits of growing mushrooms.

1 typical case and analysis

1.1.1 typical case case 1: in late April 1992, the author just went to Dongjiang Edible Mushroom Factory in Wudu County as a technical guide. From April 21 to 25, the daily minimum temperature was 5.5 ℃, the daily maximum temperature was 19.0 ℃, the daily average temperature was 12.8 ℃, the daily maximum temperature in the mushroom shed was 22.3 ℃, the daily minimum temperature was 11.5 ℃, and the daily average temperature was 16.7 ℃, which was higher than 4 days 6 ℃ outside the greenhouse. The relative humidity of the air in the shed is 80%-90%, which is suitable for mushroom production, and the clam wall produces a large number of young buds, and the growth and development is normal. From April 26 to 30, the environmental temperature suddenly rose to the daily maximum temperature of 32.5 ℃, the daily minimum temperature of 14.8 ℃ and the daily average temperature of 23.6 ℃, resulting in the daily maximum temperature of 37.6 ℃, the daily minimum temperature of 19.7 ℃ and the daily average temperature of 26.8 ℃. From April 29 to 30, a large number of mushrooms wilted and died. After inspection, the recent greenhouse did not spray any pesticides, everything management is normal, to the market survey, found that other greenhouse mushroom farmers also have a similar situation. Case 2: from March 13 to 17, 1998, the weather continued to be clear and the temperature rose rapidly. The author planted Pleurotus ostreatus in the courtyard of the Meteorological Bureau. At that time, the daily maximum temperature was 20.4 ℃, the daily minimum temperature was 5.8 ℃, the daily average temperature was 13.2 ℃, the daily maximum temperature was 26.5 ℃, the daily minimum temperature was 11.6 ℃, the daily average temperature was 18.4 ℃, and the Pleurotus ostreatus fruit body grew normally. From March 18 to 20, it was attacked by the extra cold air in the north. A rare cold wave cooling weather occurred. The ambient temperature dropped by about 15 ℃ during the day, with a daily maximum temperature of 5.0 ℃, a daily minimum temperature of-3.4 ℃, a daily mean temperature of-0.8 ℃, a daily maximum temperature of 10.0 ℃, a daily minimum temperature of 0.0 ℃, and a daily average temperature of 4.9 ℃. Yesterday, poplar and willow spit branches, spring was sullen, and it turned into an icy winter overnight. Within 3-7 days, the young buds and growing fruiting bodies of Pleurotus ostreatus in the same climate area, especially outside the shed, wilted and died on a large scale. According to the investigation, the above two damaged Pleurotus ostreatus are medium and low temperature varieties.

The most suitable temperature for medium and low temperature Pleurotus ostreatus is 10-15 ℃, while that for wide-temperature Pleurotus ostreatus is 10-20 ℃, and for most of Pleurotus ostreatus mycelium growth is 25 ℃. Case 1 showed that under the normal climatic temperature, the local Pleurotus ostreatus was in the most suitable stage of reproductive growth in late April, and the matrix nutrition was transported from the mycelium to the fruiting body, and suddenly encountered the high temperature period of daily maximum temperature ≥ 32 ℃ and daily mean temperature ≥ 23 ℃ (daily maximum temperature ≥ 35 ℃ and daily mean temperature ≥ 25 ℃), if ventilation and cooling measures were not taken in time. The matrix nutrient transport was disordered, which changed from the fruiting body to the mycelium, into the vegetative growth, causing the fruiting body nutrient supply to stop or reverse to the mycelium and wilted and died rapidly. After entering May, with the daily average temperature rising steadily to ≥ 20.0 ℃, the medium and low temperature Pleurotus ostreatus gradually entered the suitable mycelial growth temperature, so it was not suitable for fruiting body growth. Therefore, mushroom production gradually stopped, into the summer culture stage, similar to the above-mentioned sudden rise in temperature, the above phenomenon will not occur. Case 2 reflects that the local Pleurotus ostreatus is in the lower boundary of the most suitable temperature for reproductive growth under the normal climatic temperature in mid-March, the matrix nutrition flows slowly to the fruiting body, and the fruiting body grows slowly and lasts for about one hour. after the daily minimum temperature ≤ 0 ℃, the daily average temperature is about 0 ℃, if the warming and heat preservation measures are not taken in time, the matrix nutrition will be slow or stop being transported to the fruiting body. The fruiting bodies wilted and died gradually, but it was difficult to form young buds of fruiting bodies in the cold winter when the average temperature lasted ≤ 0 ℃. Therefore, even if the daily cooling range was large, the above phenomenon could not occur.

1.3 Analysis of death characteristics of fruiting body from the comparative analysis of case 1 and case 2, the death rate of fruiting body of case 1 is very fast, generally, a large number of people can die within 1 to 3 days, or even be wiped out. However, the death rate of fruiting body in case 2 was slow, usually 3 to 7 days. The mushroom body of case 1 died quickly wilting and mildew, while case 2 slowly yellowed and atrophied and died.

2 Spatio-temporal distribution characteristics of disastrous weather

Based on the analysis of the air temperature data from March to May in nine counties of Longnan from 1970 to 2004, under the condition of normal temperature, the frequency of sudden rise in temperature during this period to the occurrence of weather similar to that of case 1 is about 30%, that is, once every three years on average; the frequency of sudden cold wave and strong cooling similar to that of case 2 during this period is 40% to 50%, that is, once every two years on average. However, once these two kinds of weather occur, they have a wide range, especially since 1986, the climate has been warmer and the temperature in early spring has risen rapidly. under the normal climatic environment temperature, case 2 will occur freezing injury to Pleurotus ostreatus when the daily minimum temperature is ≤ 0 ℃ and the daily average temperature is about 0 ℃. Similarly, under the normal climatic environment temperature, case 1 Pleurotus ostreatus heat damage will occur when the daily maximum temperature ≥ 32 ℃ and the daily mean temperature ≥ 23 ℃ are suddenly encountered (the daily maximum temperature ≥ 35 ℃ and the daily mean temperature ≥ 25 ℃). The above two situations occur from March to May in spring in Longnan City, that is, the cold and warm alternating season, and similar phenomena rarely occur in other seasons.

3Preventive countermeasures

In the spring of 1999-2004, there were 3 weather events in case 2 and 2 weather events in case 1. According to the cultivation experience of Pleurotus ostreatus for many years, through the research and analysis of the cultivation site, construction mode and management method of Pleurotus ostreatus, we have formulated more scientific defense measures. through experiments in the past five years and compared with conventional methods, the effect of disaster reduction is remarkable, and there is basically no case 1 and case 2 phenomenon. In the survey, it is found that 50% to 60% of the mushroom sheds with conventional management methods have disasters such as case 1 and case 2, resulting in large losses. The preventive measures are summarized as follows:

3.1 actively listening to the weather forecast and taking effective measures to prevent it is one of the effective ways to prevent meteorological diseases of Pleurotus ostreatus. In spring, the production of Pleurotus ostreatus is arranged according to the medium-and short-term weather forecasts issued by local meteorological departments. if it is predicted that the temperature will continue to rise in the near future, when there is a high temperature period, we should pay attention to open the ventilation windows of each mushroom shed in time, increase ventilation and heat dissipation, and block direct sunlight with grass curtains. In addition, when building a mushroom shed, the site with good ventilation should be reasonably selected.

3.2 there are many abandoned caves in Longnan mountain area. Actively using some abandoned artificial caves or natural caves in Longnan mountain area to cultivate Pleurotus ostreatus is also a feasible way to prevent Pleurotus ostreatus meteorological disasters. The investigation found that the phenomenon of case 1 and case 2 seldom appeared in the cave planting Pleurotus ostreatus. Because the annual air temperature of the cave is warm in winter and cool in summer, the temperature outside the cave changes sharply, which has little effect on the air temperature inside the cave. As long as attention is paid to improving the lighting and ventilation conditions inside the cave, Pleurotus ostreatus can be safely produced in the four seasons in the cave.

3.3 the study shows that when Pleurotus ostreatus is cultivated in a semi-pit greenhouse, the temperature in the greenhouse changes little due to the influence of ground temperature. before the arrival of low temperature and cold air, straw curtain should be used to cover the greenhouse in time to reduce the cooling range as far as possible, so that the young buds of Pleurotus ostreatus can grow normally. After the snow stops and the weather is fine, the curtain can be opened properly during the day, and the curtain can be covered at night. After the environmental temperature is normal, enter the normal management. After the arrival of the high temperature weather, opening the ventilation window of the mushroom shed in time to block the direct sunlight and minimize the heating range and speed is also one of the effective ways to prevent meteorological diseases of Pleurotus ostreatus.

3.4 in addition to the above prevention methods, it is also a feasible way to select excellent varieties and scientifically arrange the temperature type of varieties according to season.