How to prevent and control tomato bacterial wilt

Tomato bacterial wilt is a very common disease, and the disease occurs very suddenly. So here is how to better prevent it:

(1) Symptoms of tomato bacterial wilt:

Although the infection occurs in the seedling stage, no symptoms are shown until the early stage of tomato fruit setting, when the leaves on the top, bottom and middle of the diseased plants wilt one after another. This is usually obvious at noon and returns to normal after dusk. If the soil is dry and the temperature is high after the disease occurs, the plant will die after a few days. The wilting and death of the diseased plant is very short. When the plant dies, it remains green, with only the leaves becoming slightly lighter in color, so it is called bacterial wilt. The roots of the diseased plant, especially some small lateral roots, turn brown and rot and disappear. If you cut the base near the surface, you can see that the vascular bundle has turned brown. If you squeeze it with your fingers, milky mucus will be secreted from the duct.

(2) Pathogens and conditions of tomato bacterial wilt:

Tomato bacterial wilt is a bacterial disease caused by Pseudomonas solanacearum infecting the vascular bundle. The pathogen overwinters on diseased residues in the soil or lives a saprophytic life directly in the soil. It can generally survive for about 14 months and spreads with rain, irrigation, farm tools and farming operations. The pathogen invades the plant body through wounds at the root or stem base, reproduces in the vascular bundle, and spreads along the upward flow of the duct fluid, destroying or blocking the duct, causing tomato water shortage and wilting. High temperature and high humidity can easily induce bacterial wilt. In addition, weak seedlings, continuous cropping for many years, root damage due to tillage, waterlogging in low-lying areas, or excessive water control and uneven dryness and wetness can all aggravate the occurrence of the disease.

(3) Prevention and control measures for tomato bacterial wilt:

① Choose varieties that are resistant to bacterial wilt.

② Cultivate strong seedlings or graft seedlings. Wild tomato CH-Z-26 can be used as rootstock for grafting.

③ Shade seedling cultivation is adopted in summer and autumn.

④ Chemical control: In the early stage of the disease, use 800-1000 times diluted 50% dichlorvos wettable powder, 4000 times diluted 72% agricultural streptomycin sulfate soluble powder, 400 times diluted 50% DT wettable powder, or 500 times diluted 25% copper chelate aqueous solution to irrigate the roots, 0.3-0.5 liters per plant, irrigate once every 8-10 days, and irrigate 2-3 times in a row.