Pest and Disease Control Methods and Key Technical Points for the Chinese Medicinal Herb Amomum villosum

1. Diseases

Seedling blight: Caused by a species of Phytophthora fungus. It overwinters as mycelium and spores attached to diseased leaf remains, and infects in April of the following year. When temperatures are high from May to August, the seedling bed is overly shaded, ventilation is poor, humidity is high, and low-lying areas collect water, the disease occurs easily. After infection, the leaves become semi-transparent and water-soaked, drooping downward. In severe cases, it spreads rapidly to the leaf sheaths and lower leaves, causing the entire plant's leaves to dry up and die. Control methods: Choose a location with convenient drainage and irrigation, good ventilation, and moderate shade for raising seedlings; before sowing, spray the seedbed with 20% formalin solution for disinfection; from March to April, adjust the shade density promptly, improve drainage, and increase the application of plant ash; promptly pull out and burn diseased seedlings, then spray with 1:1:300 Bordeaux mixture or 50% thiophanate wettable powder at 1000 times dilution, once every 10 days, for 2-3 consecutive applications.

Leaf spot and blight: Caused by a species of Deuteromycete fungus that infects leaves and leaf sheaths, occurring year-round. It occurs easily under extensive management, when the planting site is overly exposed to the sun or has long periods of damp shade and standing water, and when the seedling population grows poorly. It is especially severe after winter drought and frost. Control methods: Remove and burn diseased plants along with cutting of seedlings; maintain appropriate shade density and increase the application of plant ash; during winter drought, spray water appropriately to promote robust plant growth; in the early stages of disease, use 50% thiophanate or 50% amobam at 1000 times dilution, or 50% colloidal sulfur at 150 times dilution, once every 10 days until controlled.

Fruit blight: Commonly known as fruit rot. Caused by a species of algae-like fungus. It mostly occurs during hot, rainy seasons, when plant density is high, shade density is high, low-lying areas collect water, and nutrient accumulation is insufficient. It mainly damages fruits and fruit clusters, causing fruit drop and even rot. It generally reduces yield by 20-30%, and in severe cases by more than 50%. Control methods: After harvest from October to November each year and from February to March of the following year, clear away dead branches and fallen leaves, cut out diseased, dead, and weak seedlings, and burn them in a centralized manner; control plant density at a reasonable level; apply organic fertilizer containing calcium superphosphate, and apply a mixed powder of lime and plant ash at a 1:2-3 ratio, 15-20 kg per mu, to promote robust seedling growth and enhance disease and cold resistance; in spring, dig drainage ditches and pay attention to removing standing water; during the young fruit stage, create ventilation channels through the seedling population to improve air circulation; when fruit disease occurs, harvest and process as early as possible; during the young fruit stage, spray 1% formalin or 0.2% potassium permanganate solution at 50 kg per mu, or spray 50% thiophanate or carbendazim at 1000 times dilution, once every 10 days, for 2-3 consecutive sprays.

2. Pests

Yellow shoot fly (stem borer): The larvae bore into and feed on young Amomum villosum shoots, causing the growing point to stop growing or rot, resulting in dead hearts. It occurs more severely during dry, low-rainfall seasons or on higher-elevation planting sites. Control methods: Promptly cut off and burn infested young shoots in a centralized manner; strengthen inspection; during the peak emergence period of adults and the peak hatching period of eggs, spray with 40% dimethoate, once every 5-7 days, for 2-3 consecutive sprays.

Field rats: Mainly the large bandicoot rat. They damage Amomum villosum flowers and fruits from April to August each year. After damage, the flowers are incomplete, the fruits are bitten and broken, and the seeds are eaten clean, seriously affecting yield. Control methods: Rat traps and rat cages can be set up in the Amomum villosum field in the evening for manual capture; alternatively, roasted fragrant grain, bran, or miscellaneous grains, cooked vegetable oil, and zinc phosphide can be mixed at a ratio of 100:3:4 to make poisoned bait for trapping and killing.