What diseases does Chuanxiong have and its prevention methods?

① Root rot. It often happens near the harvest. In the early stage, there was no obvious lesion in the shoot, the inside of the rhizome turned yellow-brown, and the root system rotted first. In severe cases, the roots rot and the whole plant withers and dies. Prevention and control methods: eliminate the rotten stems at the roots; Prevent water accumulation on the ground and choose soil with good drainage for farming; At the early stage of the disease, special irrigation was used to prevent and cure the disease.

② Sclerotinia sclerotiorum. After the onset, the lower leaves turn yellow, the roots are wet and rotten, the base of the stem is dark brown, slightly sunken, and finally rotten into a circle. The upper part of the ground withered and collapsed, and white mycelia of different sizes and irregular black sclerotia of rat feces could be seen at the top of rhizome, the base of stem and the surrounding soil surface. Prevention and control methods: do a good job in cultivating and selecting Poria cocos; Rotating; Prevent water accumulation in the field; Sporadic diseases are treated with 50% clonidine wettable powder 1 kg and lime15 ~ 20kg, which are scattered on the stem base of diseased plants and the surrounding soil surface, and can only be harvested more than 10 days after application, so as to ensure safety.

③ Powdery mildew. Leaves and branches appear gray powder, which is easily confused with downy mildew. Downy mildew is distributed on the back of leaves, and powdery mildew is distributed on both sides of leaves. Prevention and control: cultivate disease-resistant varieties and disinfect seeds; Pull out the diseased plants and burn them; Strengthen field management and keep soil moisture; Spraying 0.2 ~ 0.3 Baume lime-sulfur mixture or 50% triamcinolone acetonide and thiophanate-methyl at the initial stage of onset.

④ Root knot nematodiasis. Wound the root. The disease occurred in Hebei province, and lime nitrogen can be used as fertilizer to kill nematodes. Centralized treatment of sick and disabled plants; Using inverted planting method to keep seeds and choose disease-free stems; Before planting, treat the soil with 40 ~ 60 kg drip irrigation mixture every 667 m 2, apply it into the ditch, and cover it immediately after application.