How to prevent tomato bacterial wilt

Tomato bacterial wilt is a sudden disease, which is more harmful in summer with high temperature and humidity. The greenhouse cultivation mainly affects tomato cultivation after autumn extension or autumn and winter.

　　 (1) Symptoms: Although there are infections in the seedling stage, they do not show symptoms. Until the early stage of tomato fruit set, the top, bottom and middle leaves of the diseased plants appear to be wilting, usually at noon, and return to normal after the evening. If the soil is dry and the temperature is high after the onset , it will die after a few days. The wilting time of the diseased plant is very short. When the plant is dead, the plant remains green, and only the color of the leaves is slightly lighter, so it is called green wilt. The roots of the diseased plants, especially some small lateral roots , become brown and spoiled and disappear. Cut the base at the near surface and you can see that the vascular bundle turns brown. When squeezed with your fingers, the turbid mucus is secreted from the catheter.

　　 (2) Pathogens and pathogenic conditions: Tomato bacterial wilt is a bacterial disease caused by Pseudomonas aeruginosa infection of vascular bundles. The bacteria are overwintered in the soil in the soil or directly in the soil. Life can generally survive for about 14 months, spreading with rain, irrigation, farming tools and farming operations. Bacteria invade the roots or stem base portion wound in plants, propagation in the vascular bundles, and increased diffusion flow along the conduit, destruction or occlusion catheter, causing tomato water, wilting. High temperature and high humidity are easy to induce bacterial wilt. In addition, seedlings are not strong, continuous cropping for many years, roots in cultivating, low-lying water, or excessive water control, uneven wet and dry, can aggravate the occurrence of diseases.

　　 (3) Control measures: 1 Choose resistant varieties. 2 Cultivate strong seedlings or grafted seedlings, grafting wild tomato CH - Z - 26 can be used as rootstock. 3 summer and autumn seedlings use shade seedlings. 4 chemical control: the initial stage of the disease with 50 % enemy dry double wettable powder 800 - 1000 times liquid, or 72 % agricultural streptomycin soluble powder 4000 times liquid, 50 % DT wettable powder 400 times liquid, or 25 % ammonia copper water 500 times IRRIGATING agent, 0 per irrigation. 3 — 0 . 5 l 8 - 10 days irrigation second, and even filling 2--3 times.