Cause Analysis and Preventive measures of burning rotten Lentinus edodes sticks

From the end of June to the first ten days of August in 2003, Lishui City, Zhejiang Province, had a rare high temperature and little rain weather lasting more than 40 days. The temperature exceeded 40℃ for 14 days, among which the temperature in Lishui City reached 43.2℃, breaking through the historical extreme value and ranking first in China. It has brought serious influence to people's production and life, especially to mushroom production. Due to the damage of high temperature, black water and rotten tubes appeared in mushroom mycelium. There are 350 million bags of mushroom sticks in the whole city, of which 150 million bags are rotten due to high temperature burning, accounting for 43% of the total number of mushrooms. The remaining 200 million bags of mushroom sticks are also affected to varying degrees, causing huge economic losses. More than 40,000 mushroom farmers in the whole city have all rotted and lost their money.

In the face of this unexpected natural disaster, Lishui City Agricultural Bureau timely organized technical personnel from relevant departments to conduct on-site investigation and guidance to carry out production self-rescue. According to the investigation of the severely affected areas in each county (city), the main reason for this mushroom rot is the influence of continuous high temperature weather. However, the degree and distribution of rotten rods are closely related to the varieties selected, the geographical location, the stacking mode of bacterial rods and environmental conditions, and there are certain rules to follow. Many human factors are also the key factors that aggravate the burning of bacteria and rotten rods, and these factors can be completely avoided. For this reason, the special summary analysis is summarized as follows to guide future production.

1. Analysis of the causes of mushroom rod burning and rotten rod

1.1 The influence of rare continuous high temperature weather is the main reason for the burning and decay of mushroom rods. The mushroom hyphae are very sensitive to high temperature and stop growing above 35℃, and its limit temperature is 38℃. The hypha will die if the temperature exceeds the limit for more than 4 hours. If the temperature exceeded 40℃ for 14 days, the mycelium would die and the rod would rot if the ventilation was not good.

1.2 Variety selection is relatively single, and the altitude that violates the natural distribution requirements of varieties is the indirect reason for accelerating rot. For example, variety 135 is a low temperature and long age variety, with poor resistance and no high temperature tolerance. Generally, it requires an altitude of more than 300m to safely cross summer. In Jingning County, 135 varieties are almost adopted in the areas from 100 to 1000m above sea level, and the cultivation methods are mainly spring planted flower mushrooms. Mushroom farmers in Liandu District also chose 135 as the main variety in the area above 100m above sea level, without selecting cultivated varieties and cultivation models according to local conditions, resulting in complete annihilation. At the same altitude in Songyang County, the rotten rate of 9015 and 939 decreased greatly, only 40%.

1.3 Mushroom farmers are not aware of the safety of the mushroom sticks in summer, which intensifies the degree of burning of the mushroom sticks. In high altitude areas, mushroom farmers stack the mushroom sticks on the roof, the second floor or hang them under the beams and eaves for summer. As a result, in the high temperature season of that year, the upstairs is the hottest, almost all of which burn, while those placed on the ground are better. In low-altitude villages, only a few layers of bacteria stick near the ground survive. Although some mushroom farmers also know that the roof temperature is high, but they have fluke psychology, think that it will always rain to cool down, the result lost a good opportunity to rescue. The bacteria rods stacked on the upper floor or in the single-story brick-concrete room with poor ventilation are very serious. The main reason is that the mushroom farmers blindly expand the production scale, exceeding the capacity that the bacteria field can bear, resulting in over-dense emission and poor ventilation. In addition, many mushroom farmers underestimated the high temperature, ignored the importance of ventilation and cooling in bulk piles, and did not implement flexible management measures in time according to weather changes, resulting in greater irreparable losses.

1.4 From the technical point of view, the following conditions also aggravated the occurrence of bacterial burning: ① The production season of bacterial rods was late, and the bacterial burning with poor color conversion was serious. (2) Some mushroom farmers deliberately make the water content of the mushroom stick high when producing the mushroom stick in order to pursue the yield of the first tide, which causes the hypha vitality to decrease and makes the high temperature burn more serious. (3) In the high temperature season, some mushroom farmers still ventilate through holes and turn piles to carry bacteria sticks, which will inevitably cause the temperature of the breeding site to increase and aggravate the burning of bacteria.④ Although many mushroom farmers put the mushroom sticks outdoors in the shed for summer, and covered the shed with sunshade nets and many sunshades, they did not remove the plastic film covered on the shed (said to prevent rain). As a result, the hot air can not radiate and circulate to the outside of the shed, resulting in sultry heat and bacteria burning in the shed. Although someone kept spraying water on the shed to cool it down, it was still a futile effort.

2. Prevention of mushroom stick burning and rotten stick

Although natural disasters are irresistible, losses and lessons are also heavy, but as long as we fully improve the awareness of prevention from ideological understanding, with a rigorous scientific attitude, do a good job in the summer management of mushroom sticks during high temperature, it is possible to reduce the possible losses.

2.1 Scientific and rational production should be arranged strictly according to the technical regulations of shiitake mushroom, so as not to violate the biological characteristics of shiitake mushroom to arrange production according to local conditions. Special attention should be paid to the production season, variety selection and moisture content. Adjust the planting structure of mushroom reasonably, change the traditional concept, and ask for benefits from science and technology.

2.2 Because of good ventilation and fast cooling, outdoor shade can effectively reduce the occurrence of mushroom burning, which is a good way to oversummer. Shed roof and around to shade, cover the sun net or reflective film and other covers, but the roof can not be covered with plastic film, so as not to cause the shed hot bacteria burning. All around can build frame to plant pumpkin, towel gourd and other climbing vine crops, improve the sunshade effect. Shed should be thickened and built high, and the distance between the shed and the sunshade net should be more than 1m (the top of the shed is divided into two layers, the upper layer is the sunshade layer such as weeds, and the lower layer is the sunshade net). Bamboo branches, branches and other favorable ventilation materials can be selected around to improve the ventilation effect. In case of continuous high temperature weather, dig trenches around the shed and on both sides of the sidewalk inside the shed, and introduce "running horse water" to cool down. For the old mushroom shed, a comprehensive cleaning and disinfection should be carried out before entering the shed.

2.3 Strengthen the management of indoor over-summer bacteria sticks. Indoor over-summer bacteria should be sent to the bottom room with good ventilation and cool summer. The bacteria stick discharge should leave ventilation channels. To increase the cultivation of shade facilities around the room, such as set up shade, hanging shade net, etc. In high temperature mining, pay attention to scattered piles, handle them gently, avoid vibrating bacteria sticks, and should be arranged in the morning and evening low temperature period. The requirements for bulk stacking are: from the original four horizontal and four vertical stacking, to triangular or well-shaped stacking, 3~5 layers high. Close the doors and windows near noon, and ventilate and dissipate heat in the evening. In short, use all available conditions for ventilation and cooling.

During high temperature period, it is forbidden to take measures such as puncturing holes for ventilation and turning piles to prevent hypha respiration from increasing and increasing pile temperature. Puncture ventilation should be done in cool weather before high temperature and in batches in the same room. The temperature rises rapidly after piercing, and ventilation and heat dissipation should be strengthened within 2~ 3 days to prevent the bacteria rod from dying due to high temperature.

2.4 Do a good job in the treatment of contaminated bacteria rods. For early local rotten rods, it can be treated by digging out rotten bacteria blocks to healthy hyphae, and then applying quicklime solution or a slightly higher concentration of disinfectant to prevent and control the further expansion of bacteria. For the fungus tube that has been completely stuffed and burned, it can be broken into bags and dried for reuse. Can produce coprinus, Agaricus blazei, Pleurotus eryngii and so on. Lentinus edodes rod could be produced again before September in plain area, but varieties with short age, such as L66, L33, etc., should be selected. When using contaminated materials, adjust pH value with quicklime water and prolong sterilization time. It is best to add new materials, which is conducive to the development of bacteria.