symptom
There are circular lesions on the leaves, the edges are brown, slightly raised, the center gradually becomes taupe, and slightly sunken, and black mold layers are formed on the back lesions, which are conidiophores and conidia of the pathogenic bacteria.
Pathogen Heterosporium variabile Cooke, also known as Spinach coal spot Tumor Helminthes, belongs to the fungal kingdom
Ascomycota Tumor Helminthes genus.
Transmission routes and disease conditions
The fungus overwinters latently in the diseased part with hyphae. When the conditions are suitable, conidia are produced for infection, and it is easy to get sick in warm and rainy weather.
Prevention method
①Clear the diseased residues in time after harvesting to reduce the initial source of bacteria in the field.
②Adopt formula fertilization technology, reasonably close planting, timely and appropriate watering, and prevent field water accumulation after rain.
③ Spray 40% carbendazim suspension 500 times liquid or 10% difenoconazole water dispersible granule 900 times liquid or 40% flusilazole EC 5000 times liquid, 560g/L azillabacterium chlorothalonil suspension in the early stage of disease 600 times solution
