Anthracnose of eight Immortals

Tianjin, Hebei, Liaoning, Henan, Guangdong, Shanghai, Jiangsu, Zhejiang, Fujian, Sichuan.

[symptoms] mainly occur on the leaves. The lesions are brown dots at first and round after enlargement, with purplish brown to blue-black edges, light brown to grayish white in the center, with whorls and small black spots in whorls. Plaques vary in size, ranging from 1 mm to lO mm.

[pathogens] the pathogens are fungi, Colletotrichurnhy-drangeae, subphylum Acanthophora and Alternaria. The conidium disk is black, the bristles are sparse, and the conidia are oval.

[incidence regularity] the pathogen overwintered on the diseased body with hyphae or conidia disk, and produced conidia in the following year, which spread by wind and rain, and mostly infected from the wound; it could be repeatedly infected in the growing season. June to September is the onset period; overcast, rainy and humid weather is conducive to the occurrence of diseases; potted plants in greenhouse can cause disease throughout the year.

[prevention and control methods]

(1) Horticultural control: timely removal of diseased fallen leaves and concentrated burning, the eight Immortals are persistent root plants. Seriously diseased plants can be cut off on the ground to grow new branches. Strengthen cultivation management to promote plant growth and enhance disease resistance.

(2) Drug control: at the initial stage of the disease, 75% chlorothalonil was sprayed, or 70% anthrax Fumei 500 times, or 70% methyl topiramate 1500 times. Or spray 60% anthrax Fumei wettable powder 800 times liquid, 50% Fumei wettable powder 500 times liquid for prevention and treatment.