Forecast of Major Diseases and Pests of Edible Fungi (2006)

The edible fungi industry has been ranked among the six major industries of agriculture in China, with an annual output of over 12 million t, becoming a distinctive and pillar industry in agricultural regions. With the acceleration of industrialization, the cultivation area of edible fungi nationwide has continued to increase by 15% annually, among which the number of medium-temperature and high-temperature varieties has grown, the types of diseases and pests have increased, and the degree of damage has worsened. Through multi-point disease and pest surveys and information collection across the country, the occurrence status of diseases and pests in major edible fungi production areas nationwide in 2005 was summarized, and on this basis, the occurrence trend of major diseases and pests in 2006 was forecast, so as to remind mushroom farmers to take preventive measures early, reduce the severity of diseases and pests, stabilize output, improve quality, and ensure food safety.

1 Occurrence Status of Diseases and Pests in 2005

1.1 Major Affected Varieties The edible fungi with many types of diseases and pests and severe damage include Agaricus bisporus (button mushroom), Pleurotus pulmonarius (Xiuzhen mushroom), Grifola frondosa (maitake), Agrocybe cylindracea (tea tree mushroom), Pleurotus ostreatus (oyster mushroom), Coprinus comatus (shaggy mane), Pholiota nameko (nameko), Volvariella volvacea (straw mushroom), Auricularia auricula-judae (wood ear), Agaricus blazei (himematsutake), Ganoderma lucidum (reishi), and other varieties.

1.2 Major Pests ① Mushroom gnats: There are many kinds of mushroom gnats that damage edible fungi, such as Mycetophila spp., Lycoriella mali, and Bradysia spp. Among them, medium- and low-temperature varieties such as button mushroom, maitake, himematsutake, oyster mushroom, Xiuzhen mushroom, wood ear, and nameko are severely damaged, followed by lighter damage to varieties such as king oyster mushroom, shaggy mane, hairy wood ear, Panus giganteus, and Pleurotus pulmonarius. The occurrence areas cover all edible fungi cultivation regions nationwide. Yield losses caused by mushroom gnat damage vary depending on variety and control measures. For example, the damage rate of tea tree mushroom reaches 85%, with yield losses of 10%-30%; the damage rate of Xiuzhen mushroom reaches 70%, with yield losses of 15%-20%; the damage rate of himematsutake reaches 60%, with yield losses of 10%-20%; followed by button mushroom, wood ear, and hairy wood ear with a damage rate of 50% and yield losses of 10%-15%. ② Mites: The mite populations damaging edible fungi vary by region. In mushroom farms in Fujian and Zhejiang, Caloglyphus besaralis and Brennandania lambi are predominant, while in Jiangsu, Anhui, Sichuan, and Shandong, Tyrophagus putrescentiae and Caloglyphus shanghaiensis are predominant. Mite damage commonly occurs in mushroom houses that have been in cultivation for more than 3 years, especially severe in button mushroom and enoki mushroom cultivated on the surface layer, followed by tea tree mushroom, straw mushroom, reishi, himematsutake, and hairy wood ear. Due to improper pesticide use and long-term application of insecticides with no acaricidal effect in mushroom houses, the pest sources have shown an outbreak trend after years of reproduction. In 2005, the mite damage rate of button mushroom nationwide reached over 60%, with yield losses of 10%-20% or more, and in a few areas, yield losses exceeded 50%. In some areas of Jiangsu, enoki mushroom, straw mushroom, and tea tree mushroom were infested by mites during the spawn production period and had to be discarded. ③ Phorid flies: Edible fungi varieties severely damaged by phorid flies include oyster mushroom, Xiuzhen mushroom, himematsutake, and high-temperature button mushroom that fruit at high temperatures, followed by shaggy mane, hairy wood ear, tea tree mushroom, and oyster mushroom. High-temperature button mushroom and oyster mushroom are the main varieties damaged by phorid flies. In some areas of Jiangsu, Zhejiang, and Anhui, the mycelia of high-temperature oyster mushroom were completely consumed, resulting in total crop failure. ④ Nematodes: Nematodes are one of the pests whose occurrence area and degree of damage have risen rapidly in recent years in straw-rotting varieties such as button mushroom. Due to improper selection of control agents, they have developed from a weak population to a dominant population. Button mushroom is commonly damaged across all regions nationwide, with yield losses of 10%-30%, or even total crop failure.

1.3 Major Diseases ① Mycogone perniciosa: Button mushroom is commonly damaged, especially with high occurrence in mushroom sheds that have been continuously cultivated for 3-4 years. The damage is severe, and Mycogone perniciosa has become a major obstacle restricting the further development of button mushroom in China. Mycogone perniciosa disease occurs in all button mushroom production areas nationwide, with a damage rate of over 60% and yield losses of 10%-30%. ② Bacterial diseases: These are prominent in mushroom sheds with high temperature, high humidity, and high cultivation density. Varieties with severe damage include spring button mushroom, black varieties of oyster mushroom, and enoki mushroom, followed by wood ear, hairy wood ear, and nameko. Symptoms include brown spots, black spots, deformity, and rot. ③ Slime molds: This disease has shown an upward trend in recent years, with severe damage in varieties that fruit at high temperatures such as oyster mushroom, tea tree mushroom, nameko, and hairy wood ear.

2 Forecast of Major Diseases and Pests in 2006

The winter temperature in 2005 was lower than usual and lasted longer, which could effectively freeze and kill eggs on the ground surface, reduce pest sources, and delay the disease and pest occurrence period. However, many varieties were overwintered in greenhouses, where the temperature inside the greenhouse remained stable above 5°C and the temperature inside the substrate reached above 8°C. Most insect pathogens could slowly reproduce, and the base number of disease and pest sources was relatively high, laying hidden dangers for pest outbreaks in spring and summer. Therefore, it is expected that the occurrence amount and damage degree of diseases and pests in 2006 will further worsen on the basis of 2005. Based on the winter disease and pest occurrence status in each production area, the distribution and severity of diseases and pests in major production areas in 2006 are forecast as follows.

2.1 Mites, nematodes, Mycogone perniciosa, and bacterial diseases mainly occur in new areas cultivated for the past 3-5 years, such as mushroom production areas in Jiangsu, Shandong, Henan, Zhejiang, and **.

2.2 Bacterial yellow blotch disease This disease is highly prone to occur in oyster mushroom sheds across the country under conditions of high temperature, high humidity, poor ventilation, and excessive numbers of bags. Dark-colored varieties are severely damaged. Brown blotch disease and black rot of enoki mushroom are prone to occur during early autumn bag-making and fruiting in parts of Zhejiang and Xuzhou, Jiangsu.

2.3 Phorid flies Phorid flies remain the main disease and pest of oyster mushroom, button mushroom, himematsutake, and other varieties during the high-temperature season.

2.4 Mushroom gnats In the fruiting period of medium- and low-temperature varieties in major production areas nationwide, mushroom gnats are the main pests, especially Xiuzhen mushroom, tea tree mushroom, straw mushroom, and king oyster mushroom as the main targets of damage.

2.5 Slime molds Slime mold infection is prone to occur during high-temperature periods in varieties such as nameko, oyster mushroom, and reishi cultivated with soil casing on the ground.

Other pests such as gall midges, springtails, noctuid moths, and Morophagoides spp. are locally occurring pests.

3 Prevention and Control of Diseases and Pests

To ensure product safety, the plant protection policy of giving priority to agricultural control with chemical control as a supplement should be followed, and comprehensive control of diseases and pests should be carried out. The following control measures are proposed for reference: ① Timely remove fruiting bags seriously infected by diseases and pests during the overwintering period, and clear away residual and rotten mushrooms in mushroom sheds. ② Movable mushroom sheds should be relocated after 2-3 years of use, and concentrated placement of multiple mushroom sheds should be avoided. ③ The same variety should not be planted year-round in the same greenhouse; instead, rotation with varieties not easily infected by the same types of diseases and pests should be adopted. For example, enoki mushroom sheds should not be followed by straw mushroom or button mushroom, to prevent continuous reproduction of mites and mushroom gnats. ④ Using 100-mesh insect-proof nets to cover cultivation sheds can effectively block the invasion of pests with a body size of more than 1 mm, such as mushroom gnats, phorid flies, noctuid moths, grain moths, termites, slugs, and snails, significantly reducing invading pest sources. Spraying pesticides on the insect-proof net can kill adults resting on the net, effectively reducing the next generation of pest sources. ⑤ Strengthen preventive treatment work. Measures such as shed cleaning, fumigation and disinfection, soil treatment, and substrate mixing treatment can eliminate diseases and pests in the early stages of mycelial growth and fruiting.

In accordance with the spirit of the Ministry of Agriculture document "Strengthening the Management of Edible Fungi Production," pesticide varieties registered by the Ministry of Agriculture must be selected when using chemicals for control during the fruiting period, and the right pesticide should be used for the right target. Blind use of pesticides must not be practiced. For example, pests such as phorid flies, noctuid moths, grain moths, termites, slugs, and snails can be controlled by spraying Gujing (4.3% beta-cyfluthrin · abamectin emulsifiable concentrate) and fipronil (Regent) at 1000 times dilution; diseases caused by pathogenic fungi such as Mycogone perniciosa and Trichoderma spp. can be controlled by spraying Gufeng (30% thiophanate-methyl · carbendazim wettable powder), 40% prochloraz, and Sporgon at 500-1000 times dilution. Mite and nematode damage can be controlled by multiple sprays of Gujing at 500-1000 times dilution. Table 1 shows the 10 registered pesticides that can be used on edible fungi.

Table 1 Registered Pesticide Products That Can Be Used on Edible Fungi

Registration Certificate No. Pesticide Product Name Manufacturer

LS2000121 50% imazalil manganese salt wettable powder Jiangsu Huifeng Agrochemical Co., Ltd.

LS2001627 50% imazalil manganese salt wettable powder Jiangsu Nantong Jiangshan Agrochemical & Chemicals Co., Ltd.

LS20021838 500 g/L thiabendazole suspension concentrate Syngenta Crop Protection AG, Switzerland

PD20050096 40% thiabendazole wettable powder Taiwan Junnong Industrial Co., Ltd.

PD386-2003 50% prochloraz wettable powder Bayer CropScience AG, Germany

LS2003118 4.3% beta-cyfluthrin · abamectin emulsifiable concentrate Jiangsu Suke Agrochemical Co., Ltd.

LS2001918 50 g/L fipronil suspension concentrate Bayer Hangzhou CropScience Co., Ltd.

LS94793 30% carbendazim · dichloroisocyanurate wettable powder Shanxi Qixing Pesticide Co., Ltd.

LS95328 40% sodium dichloroisocyanurate soluble powder Shanxi Kangpai Weiye Biotechnology Co., Ltd.

LS20051329 30% thiophanate-methyl · carbendazim wettable powder Jiangsu Suke Agrochemical Co., Ltd.