A detailed explanation of common diseases and pests of Atractylodes macrocephala and their prevention and control techniques

Atractylodes macrocephalais a traditional Chinese medicinal herb with high economic and medicinal value. It has developed rapidly in recent years, but its cultivation requires advanced techniques. Large areas of plants often wither and die due to factors such as continuous cropping, neglect of soil disinfection, and high temperature and rain during the growing season. At the request of farmer friends who grow medicinal herbs, several common diseases and pests of Atractylodes macrocephala and their prevention and control techniques are introduced here.

I. Diseases

1. Characteristics of the main diseases. ① Southern blight. This disease mainly damages the rhizome of Atractylodes macrocephala. In the early stage of the disease, there are no obvious symptoms on the aboveground parts. In the later stage, as temperature and humidity rise, the mycelium penetrates the soil surface, and white mycelium densely covers the rhizome and the surrounding soil surface. The top shoots of the affected plants wilt and droop, and eventually the entire plant dies. Soil and Atractylodes macrocephala residues are important sources of infection for this disease. During the onset period, the mycelium spreads, and sclerotia are spread by water flow for secondary infection. The disease can occur from late April all the way to September, with the peak onset period from early June to early August during the hot and humid season. ② Root rot. This disease is a vascular system infection. In the early stage of the disease, individual lateral roots and fibrous roots turn brown and dry-rot, then it spreads to the rhizome and aboveground parts, causing the rhizome to dry-rot and the branches and leaves to wilt. Soil and diseased Atractylodes macrocephala residues are the main primary infection sources. Frequent activity of underground pests aggravates the occurrence of this disease. The disease occurs when the temperature is 22°C to 28°C and the relative humidity is 80% to 90%. It begins in mid-April, with the peak onset period from June to July. ③ Iron leaf disease. This disease mainly damages the leaves, starting from the basal leaves and gradually spreading upward. In the early stage of the disease, small yellow-green spots appear on the leaves. In the later stage, the spots expand and connect into large iron-black patches that quickly cover the entire leaf. Diseased residues are the primary infection source. It generally begins from late April to early May, with the peak period from June to August, and it develops fastest around the time of bud picking.

2. Control methods. Comprehensive measures should be adopted for control. ① Every year when planting, be sure to use trichloroisocyanuric acid for soil disinfection. ② In the early stage of the disease, spray the stem base with 50 grams of premium Wanjiafeng (copper abietate) plus Zhixin Qifeng (imported multi-element foliar fertilizer) per mu to control further occurrence of the disease. ③ Southern blight is prone to occur from May to early July and from early September to mid-October, especially in hot, stuffy, rainy and humid weather. If wilted plants are found in the field during inspection and there is white matter at the stem base, immediately pull out the diseased plants, scatter lime, and spray the stem base with 800-fold dilution of Zhixin 101 or Keshade (cupric hydroxide) plus 50 grams of premium Wanjiafeng (copper abietate) plus Guofeng (high-potassium foliar fertilizer) per mu. ④ From early June to early September, root rot, iron leaf disease and damping-off are prone to occur. Immediately after bud picking, carry out chemical control, spraying the whole plant with 40 milliliters of 72.2% Pumeite aqueous solution plus 35 grams of trichloroisocyanuric acid plus high-potassium fertilizer mixed with water per mu. Apply once every 10 days for 3 consecutive times.

II. Pests

At the seedling stage, mainly control underground pests such as white grubs, black cutworms and mole crickets. Mix 1.5 kilograms of 50% phoxim emulsifiable concentrate or 48% chlorpyrifos emulsifiable concentrate with poisoned soil and broadcast it; from emergence to harvest, according to the degree of aphid occurrence, spray 60 milliliters of 0.36% matrine aqueous solution per mu or a 1000-fold dilution of 3% Shayawang (acetamiprid).