From late June to early August 2003, Lishui City in Zhejiang Province experienced one of the most severe heatwaves in its history, with temperatures exceeding 40°C for 14 consecutive days. The peak temperature reached an alarming 43.2°C, breaking historical records and ranking as the highest in the country. This extreme weather had a profound impact on daily life and particularly devastated the shiitake mushroom industry. The high temperatures caused the mycelium to suffer from black water formation, rotting, and even complete destruction of the mushroom substrates.
A total of 350 million mushroom logs were affected, with 150 tons suffering from bacterial rot due to the high temperatures—accounting for 43% of all the mushrooms cultivated that year. An additional 200 million logs were also impacted to varying degrees, leading to massive economic losses. Over 40,000 households completely lost their mushroom cultures, suffering devastating financial consequences.
In response to this natural disaster, the Lishui City Agricultural Bureau quickly mobilized technical staff to conduct on-site investigations and provide guidance for recovery efforts. Field assessments revealed that while the high-temperature weather was the primary cause of the damage, other factors such as the type of mushroom variety used, the location of cultivation, and the stacking methods played significant roles. Some human errors, including improper ventilation and overstocking, also contributed to the problem. These issues could have been avoided with better planning and management.
The causes of the rod burning were analyzed in detail. First, the prolonged high temperatures were the main factor, as the mycelium is highly sensitive to heat. Above 35°C, growth stops, and at 38°C, it can die within four hours. With temperatures above 40°C for more than two weeks, poor ventilation led to widespread death of the mycelium, resulting in rotten rods.
Second, the selection of mushroom varieties was a contributing factor. Many farmers used varieties like 135, which are not suited for low-altitude areas. For example, in Jingning County, where the altitude is between 100 and 1,000 meters, the use of 135 varieties led to severe damage. In contrast, areas like Songyang County, which used more resilient varieties like 9015 and 939, experienced much lower rates of rod rot—only 40%.
Third, many mushroom farmers lacked awareness about proper summer management. Some placed the logs on rooftops or second floors, where temperatures were extremely high. Others underestimated the risks and failed to implement adequate cooling measures, leading to further losses.
Fourth, several technical mistakes exacerbated the problem. Some farmers delayed production, leading to weaker mycelium. Others intentionally kept the moisture content high, reducing viability. During hot periods, unnecessary handling and puncturing of the logs increased internal temperatures, worsening the damage.
Although natural disasters are beyond control, the lessons learned from this event are invaluable. By improving prevention strategies and adopting scientific management practices, future losses can be significantly reduced.
To prevent similar incidents, it is essential to follow technical guidelines when arranging production. Farmers should select suitable varieties based on local conditions and avoid violating the biological characteristics of shiitake mushrooms. Proper timing, species selection, and moisture control are crucial.
Shade houses are an effective way to manage summer temperatures. They allow for good ventilation and quick cooling, reducing the risk of rod burning. Shade nets, reflective films, and even climbing plants can enhance the shading effect. It is important to avoid covering sheds with plastic film, as this traps heat. Excavating trenches around the shed can also help cool the area through “running horse water.â€
Indoor management during summer is equally important. Logs should be placed in well-ventilated, cool rooms. Adequate spacing and proper stacking methods are necessary to ensure good air circulation. Avoiding excessive handling and puncturing during high temperatures is critical. If necessary, these actions should be done during cooler times and followed by extra ventilation.
For contaminated logs, early intervention is key. Removing the affected parts and applying lime solution or bactericides can prevent further spread. Fully sterilized logs can be reused to grow other fungi like oyster mushrooms or lion’s mane. In lowland areas, short-lived varieties can be used, and pH adjustments should be made to improve survival chances.
By learning from past mistakes and implementing better practices, the shiitake mushroom industry in Lishui can become more resilient and sustainable in the face of future challenges.
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