Control of diseases and insect pests of Corydalis yanhusuo

Downy mildew: destructive disease of Corydalis yanhusuo. In the first ten days of March, the leaves first developed the disease, and the irregular brown spots were produced at the initial stage, and the edge was not obvious. When the humidity is high, there is a layer of white downy mildew on the back of the diseased leaves, and finally the leaves rot or dry up.

Prevention methods: promote crop rotation. Due to the limited land resources in the producing area, it is difficult to fully implement annual crop rotation. In production, you can choose to be used as a plot of rice to reduce downy mildew; soak seeds with 40% ethyl phosphate aluminum 300x solution before seed soaking 10min or with 70% methyl thiophanate 500x solution or 40% carbendazim 500x solution for 4h; at harvest, remove the field withered branches and leaves in time to reduce bacterial infection. With the increase of temperature in the first ten days of March, the first spray was carried out with 40% ethyl phosphorus aluminum 250 times or compound rhubarb mixture 500 times, the second time in late March, the third in early April, and the fourth in late April.

Downy mildew of Corydalis 1. The early stage of diseased plant 2. Enlarge the diseased leaf by 3. The later stage of diseased plant was 4. Pathogens (cyst peduncle and sporangium)

Corydalis rust: the leaf surface appears round irregular green disease spot, slightly sunken, leaf back disease spot uplift, resulting in orange protruding summer spore pile. A large amount of rusty yellow powder emitted after the rupture of the summer spore pile is the summer robe, which continues to expand and re-infect. The disease spot often appears at the tip or edge of the leaf, and the edge of the leaf is locally curled. The plaque is brown and finally perforated. In severe cases, it can kill the whole leaf. Both petiole and stem may be damaged.

Prevention methods: strengthen field management, dredge drainage ditches, reduce field humidity; increase the application of phosphorus and potassium fertilizer to improve plant disease resistance; at the initial stage of the disease, spray 95% antirust sodium 400-500 times solution, Baume 0.2 degree stone sulfur mixture or 65% Dessen zinc wettable powder 500 times solution. Since the first ten days of March, it was sprayed every 7 days, alternately, 2-3 times in a row.

Corydalis rust 1. Diseased plant 2. Diseased leaf, petiole method 3. Pathogen summer spores

Sclerotinia sclerotiorum disease occurred in the middle of March and was the most serious in April. First of all, it is harmful to the base of the stem near the topsoil, when the humidity is high, the stem base decays, the plant lodges, and dies in serious cases. The soil surface is covered with white cotton-like hyphae and irregular black mouse fecal sclerotia of different sizes.

Control methods: promote crop rotation, or select former rice plots to reduce the harm of Sclerotinia sclerotiorum; Sclerotinia sclerotiorum is a relatively stubborn disease, the initial stage of the disease with 50% carbendazim wettable powder 800 times liquid, 65% Dysen wettable powder 800 times liquid or 1RV 200 times Bordeaux liquid spray, spray once every 7 days, 3 times continuously.

Insect pest

The main pests harming Corydalis yanhusuo are ground tigers, grubs and so on, but the damage is relatively mild in general years and generally does not need to be treated.