How to control Fusarium wilt of onion caused by Fusarium wilt

Onion, also known as onion, is resistant to transportation and storage, and the fat fleshy bulb is the edible part, which has a special spicy taste, can increase appetite and can treat a variety of diseases; it is not only resistant to storage, but also can be processed by dehydration. Fusarium wilt is one of the common diseases in the growth process of onion. The symptoms and control methods of Fusarium wilt are as follows:

Fusarium wilt of onion

First, symptoms: the leaves first turn yellow and gradually develop upward. In severe cases, the plant wilted and the whole leaf scorched and fell off. The infected onion plant root system is poor, the root cortex is rotten, there are few or no new roots, and it is easy to pull up. The vascular bundles from yellowish brown to dark brown can be seen by cutting open the root, stem or peeling off the stem cortex.

Second, the law of incidence: the saprophytic ability of Fusarium wilt bacteria is strong. After the decomposition of the disease residue, the bacteria can still survive in the soil for about 5 years, and the seeds can also carry bacteria. The pathogen of Fusarium wilt invades from onion root wounds or root tip cells. The disease was the most serious when the daily average temperature increased to 24: 28 ℃. The disease develops rapidly when the relative humidity is more than 80%, especially when the soil water content is high. The disease is serious because of low-lying land, lack of fertilizer, lack of phosphorus and potassium fertilizer, heavy clay, acidity of soil and application of immature fertilizer.

III. Prevention and control methods

1. Agricultural control: rotation, selection of disease-resistant (tolerant) varieties, full application of bacteria-free and fully mature organic fertilizer, and increased application of phosphorus and potassium fertilizer. The cultivation of low-lying land can be covered with high or semi-high border plastic film to prevent flood irrigation, timely drainage after rain, and no water in the field.

2. When individual onion diseased plants are found in the field, the solution can be used immediately. Use 50% carbendazim wettable powder 500 times, or 60% Fangmaibao wettable powder 600 times, or 50% carbendazim wettable powder 1000 times, or 12.5% carbendazim 200 times 300 times, or 12.5% Zhiweiling water 200 times, or 15% carbendazim 1000 times. 35% Fu ·A wettable powder 900 times solution, or 5% bacteriological clear water agent 400 times solution to pour onion roots, each plant 100 ml diluted solution, 7 times 10 days to re-irrigation.