Cultivation Techniques for Tea Tree Mushroom (Agrocybe aegerita): Growing and Fruiting Temperature Management, and Pest and Disease Control

Tea tree mushroom, also known as tea shiitake (Agrocybe aegerita), is delicious with a crisp and tender texture, a delicate fragrance and no off-flavors. The fruiting body contains 18 amino acids and a variety of mineral elements. In traditional Chinese medicine, tea tree mushroom is considered neutral in nature, sweet and warm, with effects such as removing dampness, promoting urination, and strengthening the spleen and stomach. It is one of the delicious and rare edible fungi, and is currently the most favored mushroom dish at banquets and restaurants. Its cultivation techniques are introduced as follows:

Biological Characteristics of Tea Tree Mushroom

1. Nutrition: Tea tree mushroom is a wood-rotting fungus. Because it lacks laccase activity, its ability to utilize lignin is weak, but its protease activity is strong and its ability to utilize protein is high. Therefore, increasing the proportion of organic nitrogen (such as wheat bran, rice bran, corn flour, cake fertilizer, etc.) in the cultivation substrate helps increase yield.

2. Moisture: When the water content of the tea tree mushroom cultivation substrate is controlled at 64%-67%, the mycelium grows relatively fast. If the substrate is too dry or too wet, mycelial growth is inhibited. When fruiting bodies form, reducing the relative air humidity from 100% to 85% can promote robust development of the fruiting bodies.

3. Temperature: Tea tree mushroom grows in temperate to subtropical regions, so it is relatively resistant to high temperatures and can also tolerate low temperatures. Tea tree mushroom mycelium can grow normally at 5-35°C, with the optimum temperature range being 18-28°C. The fruiting body formation temperature is 13-28°C, with the optimum being 18-24°C.

4. Air: Tea tree mushroom is an aerobic fungus and is very sensitive to carbon dioxide. A supply of fresh air must be ensured during both the mycelial growth stage and the fruiting body growth stage. However, during the fruiting body growth stage, appropriately increasing the carbon dioxide concentration can promote elongation of the tea tree mushroom stipe, thereby increasing yield.

5. Light: The mycelial growth process of tea tree mushroom usually does not require light, but its fruiting bodies have obvious phototropism. Both primordium formation and fruiting body development require a certain amount of scattered light. Therefore, during fruiting, the cultivation room should have relatively strong scattered light (500-1000 lux) to favor primordium formation and fruiting body growth.

6. pH: The pH for tea tree mushroom mycelial growth is between 4 and 6.5, with the optimum pH being 5.5-6. Below pH 4 or above pH 6.5, mycelial growth is sparse and slow.

Cultivation Techniques for Tea Tree Mushroom

1. Selection and breeding of superior strains: At present, there are many tea tree mushroom strains, such as Tea Tree Mushroom-1, Tea Tree Mushroom-3, and Tea Tree Mushroom-5 bred by the Sanming Institute of Fungi, and AS78 and AS982 from Jiangxi, among others. In our region, Tea Tree Mushroom-3 and Tea Tree Mushroom-5, which are suitable for both fresh market sales and drying, are mainly promoted. However, regardless of which strain is selected, the spawn is required to have thick, strong, dense white mycelium. It is normal for small fruiting bodies, like those of enoki mushroom, to appear on the surface of the mother culture and the cultivation spawn, but if the mycelium is sparse, weak and thin, has not fully colonized the substrate, or has colored spots or yellow liquid, it should not be used.

2. Cultivation season: Because tea tree mushroom is relatively resistant to high temperatures and can also tolerate low temperatures, it can be cultivated year-round in our region. However, cultivation in different seasons results in different yields and quality, so to achieve high yield and high efficiency in tea tree mushroom cultivation, the appropriate cultivation period must be selected. According to cultivation trials in various places, spring cultivation or autumn cultivation is suitable, especially spring cultivation, which gives higher yields. In production, fruiting is generally timed for when the spring temperature rises to 20°C, or when the autumn temperature drops to 25°C. Therefore, in our region, the suitable cultivation periods are: for spring cultivation, bag preparation in January-February, fruiting in April-May; or bag preparation in September-October, fruiting in November-December.

3. Substrate formulas

① Sawdust 36.5%, cottonseed hull 36.5%, wheat bran or rice bran 25%, light calcium carbonate 1%, sucrose 1%.

② Cottonseed hull 78%, wheat bran or rice bran 20%, gypsum 1%, sugar 0.5%, lime 0.5%.

4. Making the spawn bags

① Mix ingredients according to the above formulas based on the quantity needed for production. Raw materials must be fresh, free of mold and pests. Mix thoroughly and evenly. Cottonseed hulls can be pre-wetted in advance. The water content of the substrate should be kept at about 65%. Use low-pressure polyethylene plastic bags with specifications of 17 cm x 35 cm x 0.05 cm. Each bag holds about 0.35 kg of dry material, with a height of 14-15 cm. Fill the material with moderate firmness and leave an inoculation hole in the center with a diameter of 2-2.5 cm and a depth of 8-10 cm. Level the substrate surface, promptly put on the neck ring and insert the cotton plug (or tie tightly with hemp rope or braided cord), then carry out atmospheric-pressure sterilization. Generally, raise the temperature to 100°C within 4 hours and maintain it for 10-14 hours. Tea tree mushroom has relatively weak resistance to contaminating microorganisms, so sterilization must be thorough, and during the production process, strict precautions must be taken to prevent puncturing or abrasion of the bags so as to prevent contamination. To prevent bag puncture, the "double bag" method (putting two plastic bags one inside the other) can also be used to make the cultivation bags.

② After the substrate has been sterilized, inoculation can be carried out only after the substrate temperature drops below 30°C. The inoculation box or inoculation room should be thoroughly disinfected. The inoculation amount is 30-40 bags per bottle (bag) of spawn. During inoculation, part of the spawn should be placed into the hole reserved during bagging, and part should remain on the substrate surface, which can accelerate mycelial growth and surface colonization. After inoculation, cultivate in the dark. Tea tree mushroom mycelium recovers and colonizes slowly and is prone to contamination and pests, so after inoculation, attention should be paid to keeping the cultivation room clean, dry and ventilated, preventing the effects of high and low temperatures, and promoting uniform mycelial growth. Check frequently, and if any contaminated bags are found, remove them promptly for disposal to prevent spread. Generally, after inoculation, the mycelium can fully colonize the bags in 30-40 days.

5. Fruiting management

① Under normal conditions, tea tree mushroom can fruit 50-60 days after inoculation. Before fruiting, primordium induction management should be carried out. During primordium induction, the bags can be placed upright or stacked in a wall-style arrangement. Then remove the cotton plug or cut the tying cord, straighten the bag opening and arrange the bags to induce primordia. For upright arrangement, place about 80 bags per square meter. Allow the mycelium to shift from vegetative growth to reproductive growth. The color of the substrate surface also changes accordingly: at first there is yellow liquid, which then turns brown, and small mushroom buds appear.

② Increase the relative air humidity and maintain it at 95%-98%. Spray water in the morning and evening to retain moisture.

③ Control light intensity at 500-1000 lux and temperature within the range of 18-24°C. In this way, a large number of fruiting bodies will develop 10-15 days after opening the bags.

④ After fruiting begins, the spatial humidity must be appropriately lowered and ventilation reduced. At this time, reduce the relative humidity of the cultivation space to 90%-95%, and reduce the frequency and duration of ventilation to prevent excessive oxygen from causing early veil opening, short stipes and thin flesh. If the mushroom buds are too dense, thinning can also be carried out, leaving 6-8 per bag. With a moderate number, the growth is uniform, the shape is good and the stipe is thick; otherwise, the quality and yield of the mushrooms are affected.

⑤ Harvest when the caps of the tea tree mushroom fruiting bodies begin to flatten and the partial veil has not yet fallen off. Because the stipe of tea tree mushroom is relatively brittle and easily broken, grasp the base and pull it down during harvesting, while taking care not to damage young mushrooms. After harvesting, clean the substrate surface of the bag, pinch the bag opening closed, and let the mycelium rest and recover for 2-3 days. Then open the bag mouth, apply one heavy watering, and repeat the above management. After 5-7 days, another flush of mushrooms can grow. A total of 4-6 flushes can be harvested.

Pest and Disease Control of Tea Tree Mushroom

During the process of bag making and cultivation management, tea tree mushroom often suffers from contamination by foreign microorganisms and invasion by pests and diseases. Therefore, during cultivation, pest and disease control must be strengthened.

1. Maintain good environmental hygiene and eliminate sources of pests and diseases: Maintain good environmental hygiene inside and outside the mushroom house, clean up garbage promptly, especially rotten mushrooms, mushroom roots, discarded substrate and so on, to prevent the growth of contaminating microorganisms or adult pests from coming to lay eggs, eliminate sources of pests and diseases, and reduce pests and diseases.

2. Light trapping: The adults of mushroom gnats and mushroom flies are phototactic and can be trapped and killed with black light lamps or high-voltage electrostatic insect-killing lamps.

3. Chemical control: Spray the bags directly with a 1500-fold dilution of 5% fipronil. The pesticide fipronil has contact, stomach-poison and systemic translocation effects on mushroom gnats and flies. If larvae are causing severe damage, spray once more after three days.