Symptoms mainly affect the leaves and stems. At the beginning, there were small yellow spots on the leaves, and small chlorotic spots were also produced at the corresponding parts of the leaves. Afterwards, they produced slightly elevated pods. After the pods broke, a large amount of yellow-brown powder was scattered, namely spores of pathogens. Chrysanthemums grow very weak after infection, and do not bloom or fall heavily. The lesions on the leaves are numerous and the leaf margins are rolled up.
The pathogen Puccinia chrysanthemi Roze said that rust rust and Puccinia horiana P. Henn called the handle rust and Phakopsora artemisiae Hirat., said layer rust, are basidiomycotina fungi. Puccinia chrysanthemi is a brownish summer spore that grows on the back of the leaves, a few are on the stem, and the size l is 2mm; the summer spores are brownish-brown, spherical to elliptic, with thorns, size 30-3725-32 (μm), with 3 Bud hole, raised on the rise. The teliospores are heaped on the dorsal or petiole and stem, and are l-2mm in size, dark brown or black; the winter spores are brownish-brown, obovate to elliptic, 38-5523-32 (μm) in size. The P.horiana teliospore is tan-brown, 2–5 mm in size; the teliospores are brownish-brown, oblong to spindle or rod-shaped, 30 to 5211–17 (μm) in size, slightly deflated at the septum, and narrow at the base , smooth, light yellow or colorless handle, handle length 50μm, do not fall off. Phakopsora artemisiae urediasporidium is produced under the foliar epidermis, only later cracking; side silk sticks, straight or curved, colorless to. Nearly colorless, long 38-41.5μm; summer spores light yellow, oval to oval, with short thorns, bud hole is not obvious.
Transmission routes and pathogenic conditions The rust bacteria lurked in the buds for winter and spread with the seedlings. Chrysanthemum cultivated in open field is susceptible to disease in the late autumn and rainy conditions. There is a difference in the resistance of the stalk rust between the cultivars.
Prevention and control methods (1) Use Taojinshan, Wu Ji and other disease-resistant varieties. (2) Strengthen cultivation and management, remove diseased leaves and diseased bodies in time, and concentrate deeply buried or burned; use formula fertilization techniques, apply sufficient decomposed organic fertilizers, avoid continuous cropping, and keep air and light transmissive. (3) At the beginning of the disease, spraying 15% triadimefon WP 1000 times solution or 20% triadimefon EC 1500 times, 25% deconcentration oil 3000 times solution and 40% DuPont Nova Emulsion 9000-10000 times. The drug was stopped 7 days before harvest.
Forehead thermometer,baby thermometer,digital thermometer,infrared thermometer
Shenzhen urion Technology Co., Ltd. , https://www.urionhealth.com