Techniques and Methods for Pest and Disease Control in the Medicinal Herb Jinxianlian (Anoectochilus roxburghii)

Integrated Control

1. Cultivate robust sterile test-tube seedlings: Because Jinxianlian grows slowly and rarely flowers and sets fruit, making seed propagation difficult, tissue culture is generally used in production for artificial propagation. Using biotechnology tissue culture techniques, select a high-efficiency culture medium, combine it with the optimal plant growth regulators, and carry out hardening-off of the seedlings in a scientific and reasonable manner to cultivate robust sterile test-tube seedlings.

2. Soil disinfection in the greenhouse: Artificial cultivation of Jinxianlian mainly uses greenhouse cultivation. Before planting, use smoke agents such as sulfur or chlorothalonil to disinfect the soil and space of the greenhouse.

3. Reasonable use of media: When transplanting tissue-cultured seedlings to the field, use rice husk burned until black, burned through but not turned white, as the medium. This rice husk has excellent water absorption and permeability, and is rich in Mg2+ and K+ ions. Its ability to accumulate nutrients can reduce the chance of sterile-state and removed seedlings suffering from pathogen damage, and helps the bottle seedlings adapt to environmental changes.

4. Reasonable layout: Create the best external conditions that are favorable for the growth of Jinxianlian but unfavorable for the occurrence of pests and diseases. When building a greenhouse, according to the growth requirements of Jinxianlian, choose both sides of a mountain stream with dense forest to ensure shade, water for irrigation, wind shelter and warmth in winter, reduced heat loss, and maintained humidity. Prepare the beds reasonably, with bed height controlled at 0.3~0.5m, to ensure that the bed surface does not accumulate water. Fertilize reasonably, apply more organic fertilizer and foliar topdressing to improve plant disease resistance. Higher air humidity helps the growth of Jinxianlian and increases plant fresh weight, but the cultivation medium should not be too wet, as excessive moisture easily leads to soft rot. Attention should be paid to measures for ventilation and light transmission.

Diseases:

Damping-off Mainly caused by Fusarium damage. Yellow-brown water-soaked lesions appear at the stem base of diseased seedlings, quickly develop to encircle the stem, and the diseased tissue rots, dries up, and constricts into a thread-like shape. The disease develops rapidly, and the seedlings quickly lodge and die, showing damping-off. Control methods: integrated control, or spraying with 75% chlorothalonil wettable powder 600-fold solution, or 64% oxadixyl wettable powder 500-fold solution, or 50% carbendazim wettable powder 600-fold solution. Spray as soon as scattered diseased seedlings are seen to improve control efficacy, once every 7~10 days, for 2~3 consecutive sprays.

Soft rot A bacterial disease, mainly harming the middle and lower inner stems and the petioles of leaves near the ground. In the early stage of onset, it is difficult to detect. In the middle stage, brown necrotic spots appear on the epidermis about 3cm from the stem base, and brown wet rot appears on the leaf veins. The middle and lower leaves of the plant turn yellow, and under high temperature they appear wilted. In the later stage, the whole plant wilts and dries but remains upright, and breaks easily when lightly bent by hand. Control methods: integrated control; and biological control: spray Xinzhi Yaosu; concentration 200 ml/L or agricultural antibiotic 751 aqueous solution 100-fold; before rain, after rain, or after watering, promptly spray 14% copper ammonia complex aqueous solution 300-fold, or 77% copper hydroxide wettable powder 500-fold, or 50% copper sulfate succinate wettable powder 500-fold

Pests:

Snails and slugs 

They eat the soft tissues of Jinxianlian such as root tips and tender buds, seriously affecting growth. Control methods: physical control, install insect-proof nets at greenhouse vents to reduce opportunities for pests to enter the greenhouse and cause damage; biological control: use biological pesticides made from bacteria, fungi, viruses, plant extracts, antibiotics, etc. to kill the pests.

Red spider mites and mites 

Adults and nymphs suck sap on the leaves, causing yellow small spots on the damaged leaf surface. In severe cases, the leaves turn yellow, scorch, and fall off, and the plant dies. Control methods: physical control; biological control: 20% compound liuyangmycin 1000-fold solution or Abamectin 2000-fold solution; chemical control: spray with 10% chongmanling 3000-fold solution or 20% fenpropathrin emulsifiable concentrate 2000-fold solution.

Black cutworm

Larvae before the 3rd instar feed on the heart leaves and leaves of Jinxianlian, eating them into small notches or net-like holes. After the 3rd instar, the larvae bite through the young stems of Jinxianlian seedlings near the ground, causing missing seedlings and broken rows. Control methods: physical control; trapping: set sugar-vinegar solution trapping basins to trap and kill pests such as black cutworm. The ratio of sugar, vinegar, wine, and water is 3:4:1:2. A small amount of insecticide (chlorpyrifos or triazophos) must be added to the sugar-vinegar solution. Cover it during the day and uncover it at night. In the early morning, at the surface soil near the bitten-off seedlings, search along the rows to catch lurking black cutworm larvae after the 3rd instar. Another trapping method: 90% trichlorfon crystal 150g, add 1~1.5L water, then mix in 5kg of crushed, roasted fragrant wheat bran to make poisonous bait, and scatter it near the seedling roots in the evening to trap and kill. Chemical control: use 90% trichlorfon crystal 100-fold solution for root irrigation.

Mole crickets

They bite and feed on the roots and stems of seedlings in the soil, causing tangled, broken-neck damage, resulting in seedling death, and cause many raised tunnels to appear in the surface soil, separating seedling roots from the soil and causing them to lose water, dry up, and die. Control methods: physical control; biological control; 5% phoxim granules 1~1.5kg plus fine soil 20~30kg mixed evenly, spread in the planting furrow, or use 80% dichlorvos emulsifiable concentrate 1000-fold solution for root irrigation.