MySheen

Licorice brown spot and its control

Published: 2024-11-08 Author: mysheen
Last Updated: 2024/11/08, ① pathogen is a kind of Cercosporaastragali among fungi, which belongs to → subphylum Cercospora →. The damaged leaves produce round or irregular disease spots, the center of the disease spot is grayish brown, the edge is brown, and there are gray-black mildew on both sides of the disease spot. Fruiting body leaves bilaterally, but mainly adaxial, with only a few brown cells; conidiophores 6-12 roots fascicled, light brown, apical color light and narrow, unbranched, with 0-5 geniculate nodes, apical

① pathogen is a kind of Cercosporaastragali among fungi, which belongs to → subphylum Cercospora →. The damaged leaves produce round or irregular disease spots, the center of the disease spot is grayish brown, the edge is brown, and there are gray-black mildew on both sides of the disease spot. The fruiting body leaves are bifacial, but the main leaves are faceted, and the conidia are only a few brown cells; conidiophores 612 are fascicled, light brown, apical light and narrowly colored, unbranched, with 5 geniculate nodes, apex subtruncate, spore scar conspicuous, 1 septum; conidium flagellate to obclavate, colorless transparent, positive to curved, base truncate to subtruncate, tip slightly obtuse, 3 septum 10.

The disease spot on the leaves of ②-susceptible plants was round to irregular, with 1~3mm in diameter, grayish brown in the center, brown on the edge, and gray-black mildew on both sides (the fruiting body of the pathogen).

The pathogen of ③ overwintered with mycelium on the remnant of the diseased plant. When the conditions were suitable in the next spring, the conidia were initially infected by wind and rain. The conidia produced on the disease spot continue to propagate and cause re-infection. It usually occurs from July to August.

④ control measures: clear the garden in autumn, concentrate on the treatment of diseased plant residues and reduce the source of disease; spray 200x solution of non-toxic high-fat film to protect; at the initial stage of the disease, spray 1:1: 15002000-fold solution of Bordeaux or 70% methyl thiophanate wettable powder, and spray 65% mancozeb 500fold solution twice during the onset period.

 
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