symptom
Also known as fusarium wilt, wilt disease. Both seedlings and adults can be susceptible to the disease, and three types have been found.
The first type is the yellowing type, which shows yellowing at the seedling stage, and the growth of the diseased plants tends to stagnate. There is also a symptom of lodging at the seedling stage, the young plants wilt, and tend to die later. The leaves do not have external symptoms, but the root system has been seriously infected. Some seedlings are only infected at the tips of fibrous roots. When the light is strong, the young plants will turn yellow, and the leaves will turn golden yellow, especially the yellowing between the veins, the veins will not turn yellow, and the leaves will not curl.
The second type is root rot type yellowing, the young leaves are curled, and later this kind of leaves turn yellow, which is characterized by yellowing along the veins, and later small veins also turn yellow, but the leaf tissue is green. Pulled roots often turn into cinnamon and reddish cinnamon.
The third type is that the diseased plant is short and small, the leaves do not change yellow or curl, and the ducts that pull out the root system, cut the stem and petiole all turn into cinnamon or red cinnamon, which is different from the first and second types.
pathogen
Fusarium oxysporum f.sp.apii (Nels.et Sherb.) Snyder& Hansen, known as Fusarium oxysporum celery specialization type, belongs to the fungal kingdom Ascomycota anamorphic Fusarium genus.
Transmission routes and disease conditions
The fungus mainly overwinters in the soil as chlamydospores and can survive for many years. When conditions are suitable, germination occurs, and germ tubes grow and invade from fine roots, causing part of the cortex to rot. After invasion, they survive in vascular bundles such as roots, root necks, petioles, etc. Mycelium inhibits the upward transport of nutrients and water. The incubation period of the disease is about 20 days. The surface is dry and the ground temperature rises rapidly, and the damage is severe. The temperature is lower than 7.7°C and higher than 36°C.
Prevention method
①Select disease-resistant varieties, apply decomposed organic fertilizers or bioactive organic fertilizers, and strengthen cultivation management to make plants grow robustly and enhance disease resistance. Watering should be done with small water and frequent watering to keep the soil moist and prevent the soil from being dry and wet or drought for a long time.
② 10 days before the onset of the disease, water 1500 times of 50% Diethofencarb · carbendazim wettable powder（
diethofencarcarbenda-zim） or 1500 times of 30% hymexazol wettable powder, and 1000 times of 50% chlorobromoisocyanuric acid soluble powder.
