symptom
Mainly damage leaves and stems. The leaves are infected with light yellow stains at the beginning, which gradually expand into taupe, round to oval lesions with ring patterns and small black spots in the center. The disease of the seed-collecting plant mainly occurs on the stem, and the lesion is fusiform or spindle-shaped, and the small grain spots arranged in the shape of black rings are densely grown on it, that is, the conidia disc of the pathogen.
pathogen
Colletotrichum dematium (Pers.: Fr.), called fascicle anthracnose; C. spina-ciae Ell.et Haslst. called spinach anthracnose, all belong to the anamorphic type of Ascomycota.
Transmission route and pathogenic conditions
The hyphae survive the winter in the diseased tissue or stick to the seeds, and become the source of infection at the beginning of the next year. When spring conditions are suitable, conidia are produced, spread by wind and rain, directly invaded by wounds or through the epidermis, and after several days of incubation, conidia discs and conidia are produced for re-infection. Heavy rainfall, low-lying terrain, over-dense planting, poor plant growth and severe disease.
Prevention method
①Plant Boza No. 9 and No. 10 early-maturing first-generation hybrids; select seeds from disease-free plants; soak the seeds in warm water at 52°C for 20 minutes before sowing, then transfer them to cold water to cool, and dry them for sowing.
②Crop rotation with other vegetables for more than 3 years.
③Achieve reasonable dense planting, avoid flood irrigation; timely topdressing, pay attention to nitrogen, phosphorus and potassium.
④Clean the field, remove sick and disabled bodies in time, take them out of the field and burn them or bury them deeply.
⑤ The shed can be sprayed with 6.5% methylsulfur-moderate dust agent 1kg per 667m21 times.
⑥ Spray 1000 times of 2.5% fludioxonil suspension or 1200 times of 250g/L azoxystrobin suspension, 700 times of 30% pentazole·carbendazim suspension, 1000 times of 25% prochloraz EC at the early stage of the disease. Double liquid, 250g/L pyraclostrobin EC 1500 times liquid, once every 7 to 10 days, continuous control 3 to 4 times.
