symptom
Celery can be diseased throughout the growth period. When the leaves are infected, the infection usually starts from the leaf tip or leaf edge. The diseased part is water-soaked dark green at first, then turns brown, necrotic and dry, and continues to develop inward. When the weather is dry, the diseased part is dark brown and dry, causing the leaves to curl. When the humidity is high, it expands from the edge of the leaf to the inside, gradually turning dark brown, and sometimes the disease grows a black mold layer.
pathogen
Alternaria sp., called a kind of Alternaria sp., belongs to the fungal kingdom Ascomycota phylum Alternaria sp.
Transmission routes and disease conditions
The fungus likes high temperature and high humidity climate conditions. The bacteria can grow between 13-38°C, and the optimum temperature is 26-30°C. The high temperature and rainy conditions in autumn make the disease prone to occur. Generally, the annual disease occurrence period is mainly affected by temperature, while the disease severity is affected by the rainfall and frequency of the appropriate period. In addition, early planting, high temperature and rainy disease is severe. The plots that are over-planted, low-lying, prone to water accumulation, poor ventilation, weak growth, and poor management often have severe disease.
Prevention method
①Clean the fields in time after harvesting, plow the soil deeply, and dig the sick and disabled into the deep.
② Use celery and celery formula fertilization technology to enhance disease resistance.
③ Seed dressing with 50% iprodione wettable powder with 0.3% seed weight.
④ Spray 1000 times liquid of 250g/L azoxystrobin suspension concentrate, 1000 times liquid of 50% iprodione WP, and 5000 times liquid of 50% fludioxonil wettable powder at the initial stage of the onset, for 2 to 3 times of continuous control.
