Control methods of licorice diseases

The main diseases of licorice are rust, brown spot and powdery mildew. The prevention and control methods are as follows:

1. Rust: yellow-brown scar spots are produced on the back of the leaves when infected, and brown powder is scattered after the epidermis is ruptured, which is the summer spore pile of the pathogen, which forms a black-brown winter spore pile from August to September, resulting in withered and yellow leaves and shedding in severe cases. Control methods: increase the application of phosphorus and potassium fertilizer to improve plant disease resistance. Remove the sick and disabled body and burn it centrally. At the initial stage of the disease, 15% trimethoprim 1000-fold solution was used, or 97% sodium 400-fold solution was sprayed to control the disease.

2. Brown spot disease: damage the leaves, and the damaged leaves produce round or irregular disease spots. The edge of the spot is brown, the middle is red, and there are gray-black mildew on both sides of the spot. Prevention and treatment methods: clear the garden in winter and deal with sick and disabled bodies. At the initial stage of the disease, 65% mancozeb or 50% mancozeb was sprayed with 1500 times of 50% mancozeb, or 70% methyl topiramate wettable powder was sprayed with 100 Bordeaux solution.

3. Powdery mildew: if the injured leaves are sprinkled with a layer of white powder, the leaves turn yellow in the later stage, resulting in poor plant growth. Prevention and control methods: clear the garden to treat the disease residue; use 1500 times of methyl topiramate wettable powder, or spray with 15% trimethoprim 800-1000 times solution.