Key Technical Points for Pest and Disease Control During the Cultivation Period of Gastrodia elata

Gastrodia elata is a commonly used traditional Chinese medicinal herb. It is a special seed plant with no roots and no green leaves; it cannot nourish itself and must rely on symbiosis with Armillaria mellea to obtain nutrients for reproduction and growth. Therefore, cultivating Gastrodia elata differs from growing green plants, and three key steps must be managed according to its growth patterns. First, the cultivation of Armillaria mellea-infected wood; second, the selection and cultivation of Gastrodia elata seed tubers; third, the symbiotic cultivation of Gastrodia elata with Armillaria mellea. In all three production steps there is a chance of contamination by miscellaneous fungi, and if any step is done poorly, especially under unfavorable conditions, it will lead to failure in Gastrodia elata cultivation.

There are two common diseases in Gastrodia elata cultivation: one is mold damage, and the other is rot disease. When Gastrodia elata is continuously cropped and water permeability and air permeability are poor, purple-brown lesions appear on the tubers. The control measures are: (1) The cultivation site should be sandy loam soil with good water permeability and air permeability; do not choose previously cropped land, clay soil or waterlogged, ponding land; (2) When cultivating Armillaria mellea-infected wood or planting Gastrodia elata, any wood found to be infected by miscellaneous fungi should be removed and not used, keeping the infected wood pure; (3) When planting Gastrodia elata and culturing Armillaria mellea, the gaps between the wood pieces should be filled solidly with sandy soil (where it cannot be filled completely, leave gaps; rainwater will accumulate there, and miscellaneous fungi are likely to grow); (4) At planting time, increase the amount of inoculum (infected wood) used, prompting vigorous growth of Armillaria mellea, thereby inhibiting the growth of miscellaneous fungi.

Rot disease and its control: seed tubers that suffer insect damage, mechanical injury or are in an unfavorable high-temperature, high-humidity environment are easily infected by miscellaneous fungi and cause rot. The control measures are: (1) Select complete, unbroken, brightly colored white-headed tubers or small tubers as the seed source; do not bruise them or expose them to the sun during digging and transport; (2) Pay attention to regulating temperature and humidity, providing the optimal conditions for Armillaria mellea growth, which has inhibited the growth of miscellaneous fungi; (3) The culture material for planting Gastrodia elata should preferably be piled, disinfected and aired in the sun to kill internal insects, pupae and fungi and reduce damage.

Gastrodia elata cultivation is a multi-step comprehensive production process, and each step requires different environmental conditions. Suitable environments make cultivation success easy, while the opposite often ends in failure. Therefore, when cultivating Gastrodia elata, one should carefully study its environmental requirements, create optimal conditions and promote good growth and development. In addition, during the production process, pay attention to increasing the dominant population of Armillaria mellea by adding more infected wood, while also ensuring that the infected wood is of good quality (at night, at about 25°C, with sufficient oxygen, the mycelium and rhizomorphs can emit fluorescence). Armillaria mellea is a medicinal and edible fungus. When culturing Armillaria mellea, to prevent contamination by miscellaneous fungi, commonly used disinfectants include carbendazim and potassium permanganate. The environmental requirements for Armillaria mellea growth and development are: (1) Soil pH: pH 55-56 is best; (2) Temperature: it can grow at 6-30°C, but reproduces fastest at 18-25°C; above 30°C it stops growing, and at 70°C it dies; (3) Humidity: air relative humidity of 80-90% and soil moisture content of 50-70% are best for growth; (4) Air: good ventilation (Armillaria mellea is an aerobic fungus; mycelial growth requires not too much air, but rhizomorph growth requires good ventilation conditions); (5) Light: not required (it can be cultivated in basements and air-raid shelters).