Licorice Pest and Disease Control Methods and Key Technical Points

(1) Rust disease: After infection by fungi, yellow-brown blister-like lesions appear on the underside of leaves; when they rupture, brown powder is released, which consists of the pathogen's telial and urediniospore stacks; in August and September, dark brown telial stacks form.

Control methods: Gather diseased plants and burn them. In the early stage, spray 0.3-0.4 degrees Baumé lime sulfur mixture or 97% dithianon sodium 400-fold solution.

(2) Brown spot disease: After infection by fungi, round and irregular lesions appear on leaves, with a grayish-brown center and brown edges; gray-black mold-like growth occurs on both the front and back of the lesions.

Control methods: Gather diseased plants and burn them. In the early stage, spray 1:1:1-160 Bordeaux mixture or 70% thiophanate-methyl wettable powder 1500-2000-fold solution.

(3) Powdery mildew: After infection by imperfect fungi, white powder appears on both the front and back of leaves.

Control methods: Spray 0.2-0.3 degrees Baumé lime sulfur mixture.

(4) Aphids, also called honey bugs or greasy bugs: Adults and nymphs suck the sap of stems and leaves; in severe cases, the stems and leaves turn yellow.

Control methods: In winter, clean the garden and bury the plants and fallen leaves deeply. During the occurrence period, spray 50% fenitrothion 1000-2000-fold solution or 40% dimethoate emulsifiable concentrate 1500-2000-fold solution or 80% dichlorvos emulsifiable concentrate 1500-fold solution, once every 7-10 days, for several consecutive treatments.

(5) Red spider mites occur around August and cause severe damage around September, mainly feeding on leaves and inflorescences. After leaves are damaged, their color changes from green to yellow, and they eventually wither. These pests mostly hide on the underside of leaves.

Control methods: Spray 0.2-0.5 degrees lime sulfur mixture with rice water or flour paste water.