Causes and control of tomato root rot

In recent years, the damage caused by tomato root rot has increased year by year, especially in the early spring. In the early April and May , the initial incidence was serious, and there were many dead trees, even ruined and ruined. The farmers lost a lot.

 

First, the characteristics of the disease

 

Root rot mainly harms the roots of tomatoes. At the beginning of the disease, brown spots appear on the main roots and stem bases, and then gradually enlarge and sag. In severe cases, the main roots become brown and rot, leading to the fading of the upper part. Longitudinal section of the base or root of the stem, the vascular bundle becomes dark brown, after which the rhizome rots and does not grow new roots. At the end of the disease, the diseased plants die and die.

 

Second, the spread of pathogens and causes of the disease

 

The tomato root rot pathogen is a fungus of the fungus, which is overwintered in the soil with mycelium and oospores. The spread in the seedbed is mainly soil, fertilizer, farm tools and watering. The germs invade from the seedling wounds and then spread by rainwater and irrigation water. High temperature and high humidity are suitable for this disease. The plots of the seedbeds, the area of ​​the water, the application of unfertilized fertilizers, the number of underground pests, and the fact that the agricultural activities cause more root wounds are more serious.

 

Third, prevention measures

 

　　 1. Agricultural measures. Do a good job in soil disinfection of seedbeds and cultivate disease-free seedlings. Level the land, do a good job of irrigation and drainage system, sorghum cultivation. Severely ill and non-japanose and melon vegetables are rotated for more than three years. Strengthen water and fertilizer management, timely and appropriate irrigation, pouring small water, avoid flooding. Drainage in time after rain, ploughing loose soil after watering and after rain. Apply fully decomposed manure, increase phosphorus and potassium fertilizer, and avoid improper application of fertilizer to burn roots. At first sight, the diseased plants were removed and burned in time.

 

　　 2. Chemical control. In the early stage of the disease, timely control of the drug, watering the seedbed with 40% ethyl phosphine aluminum wettable powder 200 times liquid or 72.2% Plex water agent 400-600 times liquid, the amount of liquid per square meter seed bed is 2-3 kg; or moving Before planting , the roots of the seedlings are soaked with 72.2% Plex water agent 400-600 times, or after transplanting, the roots are filled with 72.2% Plex water agent 400-600 times.