Enoki Mushroom Cultivation Methods and the Causes and Control of Soft Rot

Enoki mushroom (Flammulina filiformis) is a very popular edible fungus. It contains abundant nutrients, such as amino acids and protein, and also has benefits like treating constipation, promoting digestion and detoxification, but it is relatively high in value and low in yield, and is prone to soft rot. So how do you grow enoki mushroom? Why does “soft rot” occur? How do you prevent and control it?

I. How do you grow enoki mushroom?

1. Nutrient preparation

Since enoki mushroom develops from a kind of mycelium, before planting we need to prepare the nutrients for cultivating this mycelium. Usually we mainly use cottonseed hulls as the base, then add appropriate amounts of wheat bran, gypsum, sawdust and corn cobs and other materials, then pile these materials on sterilized ground, add an appropriate amount of water and stir evenly. Stir at least three times a day, and after three days the material is ready for filling.

2. Inoculation management

First we need to sterilize the filled nutrient material under high temperature or high pressure, then place the nutrient material into the inoculation room and spread it evenly on the inoculation bed, usually at a thickness of five to eight cm, then cool the nutrient material down, preferably to around 25 degrees, and finally inoculate the spawn evenly into the culture material for cultivation. One thing to pay special attention to is that during inoculation, the inoculating personnel and all utensils must be sterilized, so as not to affect the success rate of enoki mushroom inoculation.

3. Spawn-running management

The most important part of spawn-running management is managing the temperature, moisture, air permeability and other fungi in the spawn-running room. First we need to regulate the indoor temperature to around 20 to 25 degrees, then as the mycelium grows it will raise the indoor temperature, so the temperature should be appropriately lowered by two to three degrees. Generally it takes about a month for spawn running to fully succeed, so at this stage we also need to remove other fungal species from the nutrient material, so as not to affect the growth of the enoki mycelium.

4. Fruiting management

Fruiting management actually means that the mycelium has basically finished developing, and at this point we can see the fruiting bodies of the mycelium, so we need to scrape off the older spawn on the surface layer, which promotes the growth of the spawn. Next, the indoor temperature should be lowered again, kept at around 10 to 15 degrees, and the air humidity should reach at least 91 or 92 percent, while keeping the indoor air circulating. This way the enoki mushrooms that grow will be more tender and taste better.

5. Timely harvesting

Enoki mushrooms age very easily, so we need to harvest the mature ones in time. Generally, harvesting should be done when the enoki mushrooms have grown to about 12 to 15 cm. When harvesting, we should gently hold the stipe of the enoki mushroom, then slowly rock it, and finally pull the enoki mushroom out. Then carry out spawn-running management and fruiting management in the same way, so that a second harvest can quickly be reached.

II. Why does “soft rot” occur in enoki mushroom?

1. Introduction to soft rot

Enoki mushroom soft rot, also known as cotton mold disease, rot disease, etc. In Japan it is called plant wilt disease. It is a relatively common fungal disease in enoki mushroom cultivation, and mostly occurs on the 2nd to 3rd flushes of mushrooms in the middle and late stages of cultivation, with the disease being more severe in bag cultivation or bed cultivation methods.

Its pathogen is Cladobotryum varium, which belongs to the Deuteromycetes. Its mycelium is white, septate and branched. The conidiophores are erect, septate, repeatedly whorled-branched; the conidiogenous cells are nearly cylindrical, broad at the base, tapering toward the end, with a blunt tip. The conidia are elliptical, two-celled, with a few being single-celled. After 15 days of culture, thick-walled spores can be produced, in chains; some thick-walled spores can fork at the base, with a transparent short or long stalk at the base.

2. Disease symptoms

In the early stage of infection, white mycelium appears on the surface of the culture material in the fungus bags or fungus beds. When temperature and humidity conditions are suitable, it spreads very quickly, and before long the white flocculent mycelium can cover the entire surface of the culture material, that is, the pathogen's mycelium, conidiophores and conidia. After young mushroom buds are surrounded and infected by the pathogen, they cannot continue to grow and die, turning light brown. Mature fruiting bodies develop light brown water-soaked rot at the base of the stipe, and the pathogen's cottony aerial mycelium can extend upward to the cap. After the base of the stipe rots, the diseased fruiting body topples over, covered with white mycelium, completely losing its economic value. If not handled in time, no more fruiting bodies can form, and the culture material will deteriorate into a wet rot.

3. Pathogenesis

The soft rot pathogen can normally live in soil rich in organic matter and on dead organic matter. When raw-material bed cultivation or box cultivation of enoki mushroom is used, using unclean water to mix the material makes this disease very likely to occur. In cooked-material bag cultivation or bottle cultivation, the culture material has undergone sterilization treatment, so the first flush of mushrooms rarely develops the disease. In the 2nd to 3rd flushes, because of water replenishment and moisture-retaining spraying in the mushroom house, or conidia floating in the air settling onto the culture material, under conditions of relatively high temperature, excessive humidity and poor ventilation, this disease is favored to occur, and once the disease occurs, it spreads very quickly.

The pathogen infects at the base of the enoki mushroom, and the stipe turns brown and rots. It then develops upward and covers the entire fruiting body, and the affected parts become water-soaked and gradually turn into a brown soft rot. The pathogen also survives long-term in the soil, and generally enters the mushroom shed through airflow, humans, tools and insects. It can cause damage at around 10°C, especially in early spring, when the temperature gradually rises and relative air conditions are poor, it occurs extremely quickly and the damage becomes more severe accordingly.

III. How do you prevent and control “soft rot” in enoki mushroom?

1. Do a good job of environmental sanitation inside and outside the mushroom house, and use clean water free of pathogen contamination for mixing materials and for mushroom house management water;

2. During fruiting, control the mushroom house temperature at a relatively low level as much as possible and provide appropriate ventilation, to prevent water from accumulating on the surface of the culture material;

3. Once disease occurs, promptly remove it and spray a 1:200 dilution of "Shi'erKang" liquid, which can effectively control the spread of soft rot; when using raw-material cultivation, mix the material at a ratio of 600 ml (3 bottles) of "Shi'erKang" per ton of dry material.