Causes of rotting of Lentinus edodes rods and its control techniques

In recent years, some producing areas of Lentinus edodes have appeared different degrees of rotting phenomenon (that is, rotting and disintegrating during the culture period), resulting in a waste of resources and economic losses of mushroom farmers, and some areas have seriously threatened the development of mushroom industry. For example, in Qingyuan County, the decay rate of bacterial sticks reached 17% and 31% respectively in 1999 and 2003, and more than 50% in individual farmers, resulting in serious losses. In this regard, we have conducted a special investigation and research since 1997, and preliminarily explored the causes of bacterial rotting and its control techniques.

1. The cause of rotting of bacterial stick

Stick rot often occurs in the old mushroom area where it has been cultivated for a long time, and the root cause of its occurrence is the invasion and infection of competitive miscellaneous bacteria. All the factors that induce the invasion and infection of miscellaneous bacteria are the specific causes of rod rot, which can be summarized as follows:

1.1 the stress resistance of cultivated varieties is weakened.

The weakening of stress resistance is a manifestation of the degradation of varieties, which is the internal cause of rotting. Some leading varieties in the old mushroom area have been planted for many years, and the species has degraded, such as the decline of mycelial vitality, the ability to adapt to the environment and the ability to resist the invasion of miscellaneous bacteria, which can invade people and cause rot. For example, Lentinus edodes 241Mui 4 has been cultivated for a long time, its high yield and stress resistance have been obviously degraded in recent years, and its stick rot has been aggravated year by year.

1.2 mycelial damage and invasion of miscellaneous bacteria

The mycelium of the rod was directly damaged, and the miscellaneous bacteria were infected from the wound, which caused the rod to rot. This is the external cause of decay.

1.2.1 the cultivation environment is bad. Adverse environmental factors lead to hyphae growth inhibition, autolysis, stress resistance weakening or aging death, resulting in bacterial rotting, high temperature in summer, lack of ventilation, improper use of disinfectants, deterioration of raw materials and other factors may lead to decay.

1.2.2 insect damage. Mushroom pests enter the rod from the inoculation mouth and vent to grow and reproduce, and bite the mycelium directly. After the mycelium injury, the local high humidity and high nutrition environment is formed, and the competitive miscellaneous bacteria invade and infect, that is, the insect and bacteria cross-infection and the rods rot. This is the reason why the population density of the old mushroom area is high, the insect pest is serious, and the rotten stick is also serious.

1.2.3 piercing injury. In the process of cultivation, piercing instruments (iron nails, bamboo sticks, etc.) directly pierce the hyphae, miscellaneous bacteria invade infection, and then the rods rot.

1.2.4 Drug injury. The mycelia or fruiting bodies of Lentinus edodes are sensitive to most pesticides and are easy to cause drug damage. For example, dichlorvos and dimethoate have obvious toxic effects on hyphae, and mushroom farmers are more accustomed to using these conventional pesticides to control pests.

1.3 damage caused by bacteria. Stubborn parasitic bacteria or viruses directly invade or interfere, causing rods to rot.

2. Prevention and control of bacterial rotting.

According to the causes and initiation ways of bacterial stick rot, the prevention and control of bacterial stick rot should be based on prevention, supplemented by treatment, and carry out the whole cultivation management all the time.

2.1 excellent varieties are selected to purify and rejuvenate the degraded varieties.

According to the local climate characteristics, select the appropriate varieties. The varieties with strong stress resistance such as "Qingyuan 9015" and "Qingke 20" should be selected in the low altitude areas below 350m in Zhejiang province, but it is not suitable to plant varieties with weak stress resistance.

2.2 standardize cultivation management

2.2.1 transform the mushroom shed to improve the environmental hygiene of the cultivation site. Raise the height of the mushroom shed from 2.5 meters to 3.5 meters, increase the width from 3.5 meters to more than 5.4 meters, and consolidate the structure to thoroughly improve the environment of bacteria culture and mushroom production. The waste bacteria sticks left in the previous season should be cleaned in time, and the old mushroom farm should be sprayed with high-efficiency and low-toxic germicidal insecticides to reduce the pollution sources of miscellaneous bacteria and reduce the population density.

2.2.2 strictly control the dosage of disinfectants. At present, the active ingredients of disinfection boxes on the market are the same, the best dosage is 4 grams per cubic meter, not more than 6 grams. Excessive use will kill and kill the mycelium of Lentinus edodes, causing the stick to rot.

2.2.3 use wax or adhesive tape to seal off insects and bacteria from the inoculation mouth to invade the rod.

2.2.4 the operation of piercing ventilation should be standardized. The diameter of the nail should be less than 2 mm, and the hole depth should be 1mi 1.5 cm. Choose a fine day to pierce the hole, not at the tumor.

2.2.5 change indoor summer to field mushroom shed over summer. After the bacterial rod hyphae is covered with bags, it is moved to a single layer on the shelf of outdoor mushroom shed to improve ventilation and heat dissipation conditions and avoid damage to bacterial sticks by high temperature in summer.

2.2.6 reasonable pest control and disease prevention. For example, the mushroom special insecticide "Mushroom Chong Jing" with high efficiency, no side effect, non-toxicity and long effect can be sprayed once after the first piercing, and then sprayed again every two months, which can effectively control insect pests and protect bacterial sticks. Dichlorvos and other insecticides that should not be used on Lentinus edodes sticks should not be used.

2.3 Bad stick treatment measures

When it is found that the rotting rods are rotten, the rotting sticks should be selected and stacked in time to avoid mutual infection between the rods and be treated.

2.3.1 scar treatment. Remove the rotten part with a clean blade, scrub the spot cut and film with carbendazim fungicide, and then seal the film with tape to prevent water loss and insect invasion again, which is best done under aseptic conditions.

2.3.2 remaking stick culture bacteria. If you start to rot at the initial stage of the bacteria, you should decisively make the stick again, disinfect and inoculate (that is, redo it).

3. Discussion

The mechanism of rod decay is a complex subject, this paper is only a superficial study, such as the types and characteristics of competitive miscellaneous bacteria (or viruses) and the screening of specific therapeutic agents need to be further explored.