How to prevent and control tomato gray leaf spot? Latest technical method tutorial
Tomato gray leaf spot occurs frequently in tomato production. It destroys the photosynthesis of leaves, reduces tomato yield, and brings huge losses to farmers. So how should tomato gray leaf spot be prevented and controlled? Let's learn about it together.
1. Disease symptoms
Tomato gray leaf spot only harms leaves. At the early stage of the disease, the leaves are covered with small dark green round or irregularly round spots, which then spread along the leaf veins to the surrounding areas and become irregular in shape, with the center fading to gray-white to gray-brown. The lesions are slightly sunken, mostly relatively small and extremely thin. In the later stage, they are very likely to rupture and perforate, causing the leaves to break apart or even fall off.
2. Causes of the disease
The pathogen of tomato gray leaf spot can overwinter in diseased residues in the soil and on seeds. When the temperature and humidity in the following year reach the level needed for spore growth and reproduction, it will initially infect tomato plants. After that, the spores will spread with wind and rain and cause secondary infection. Long periods of warm, humid, and rainy weather are the peak period for the disease. In addition, insufficient soil fertility can also weaken plants and give the pathogen an opportunity, thus causing the plants to develop the disease.
3. Prevention and control techniques
According to the occurrence characteristics of tomato gray leaf spot, targeted prevention and control measures should be taken. First, seed disinfection should be done well during seedling raising. Before sowing, soak the seeds in warm water at 55 degrees for half an hour while stirring continuously, then remove them and dry them for later use, or soak them in a low-concentration potassium permanganate solution for half an hour, then remove and wash them before accelerating germination and sowing. During production, it is advisable to choose varieties that are resistant to both tomato gray leaf spot and viral diseases to reduce the chance of disease occurrence in the field. Cultivation management should be strengthened. Temperature and humidity management should be strengthened, and watering and dehumidification should be properly controlled to create an environment unsuitable for pathogen growth. When the disease occurs, it should be controlled in time. Strobilurin fungicides and sterol biosynthesis inhibitor fungicides have a relatively strong control effect on tomato gray leaf spot.
The above is an introduction to the prevention and control techniques for tomato gray leaf spot. We hope it can help you. To learn more related knowledge, please stay tuned to us.