Tomato powdery mildew symptoms and prevention methods

Let me tell you about the pathogens and symptoms of powdery mildew of tomatoes and how to prevent and treat it.

Tomato powdery mildew pathogen

Leveillula taurica

Tomato powdery mildew symptoms

It usually occurs in the middle and late stages of tomato growth, mainly harming the middle and lower leaves, and sometimes also the stems and fruit stalks. After the disease occurs, it spreads upward. In the early stage of the disease, small chlorotic spots appear on the leaf surface, and gradually white filaments appear, which expand to form pink spots. Sometimes pink spots grow on the back of the leaves, and yellow-green patches with unclear edges appear on the front of the leaves. Disease pattern The pathogen overwinters in the soil or spreads on vegetables such as tomatoes. The disease is prone to spread at 25-28℃ and dry conditions. The disease will be suppressed in a humid environment.

Tomato powdery mildew prevention and control methods

① Environmental control: Strictly control the air humidity to prevent the formation of a dry environment and water in time.

② In the early stage of disease control, spray 20% triadimefon emulsifiable concentrate at 2000 times, or 50% sulfur suspension emulsifiable concentrate at 300 times, or 30% solid lime sulfur mixture at 150 times, once every 7 days, and control 2 to 3 times in a row. In areas where drug resistance has already developed, spray 40% Fuxing emulsifiable concentrate at 7000 times, once every 20 days. Pay attention to the rotation of drugs.