What causes spots to appear on lettuce leaves recently?
Lettuce is one of our everyday vegetables. It tastes good, is highly nutritious, and has a distinctive way of being eaten. Its cultivation and management are simple, and many people grow some at home, picking and eating it fresh. However, during cultivation, spots appear on lettuce leaves, and these spots also spread. What is going on here? Let us take a look at the detailed introduction below.
1. Black spot disease
The spots may be caused by black spot disease. Black spot disease first affects the outer leaves, progressing from bottom to top. When it occurs, yellow-brown water-soaked spots appear on the leaves. As the disease develops, the lesions gradually expand into round or irregular yellow-brown dead spots. In humid environments, a gray-black mold layer appears on the lesions. When the disease is severe, the lesions join together into patches, causing the leaves to yellow and die, until the entire plant dies.
2. Brown spot disease
It may also be caused by brown spot disease. When brown spot disease occurs, pale yellow water-soaked spots appear on the leaves. As the disease develops, they gradually spread into round or oval dead spots. In humid air conditions, sparse gray-brown fuzzy mold appears on the leaves. When the disease is severe, the lesions on the leaves also join together into patches, forming large areas of necrotic spots, causing the leaves to age prematurely and die. These two diseases are quite similar and are relatively difficult to identify in the early stages, so attention should be paid.
3. Leaf spot disease
Leaf spot disease starts from the leaf margins. As the disease develops, the spots gradually spread, and these spots are also covered with small black granules. These granules are the pathogens of leaf spot disease. When the disease is severe, it can cause the entire plant to become infected, until the plant dies, causing great harm.
4. Prevention and control methods
Great importance must be attached to the prevention and control of lettuce diseases, with prevention as the main approach. These diseases mostly occur during the plum rain period, when humidity is relatively high, which very easily leads to bacterial growth. Therefore, attention should be paid to drainage and humidity reduction measures, and temperature regulation should also be done well. If the day-night temperature difference is too large, the resistance of lettuce will decline, giving diseases an opportunity to take hold. When sowing, the seeds and soil should be disinfected. When disease occurs, pull out the diseased plants and carry them out of the field, disinfect the diseased planting holes well, and then spray the entire area with pesticide for control.
The above is an introduction to what causes spots to appear on lettuce leaves. We hope it can help you. If you want to learn more related knowledge, please follow us.