What disease causes yellow leaves on peppers? Causes and control methods

Peppers are an essential seasoning and side dish in the daily life of people in several provinces such as Hunan and Sichuan, and peppers hold a fairly high place in our lives. The scale of pepper cultivation is also very large, and although there are many varieties of peppers, they all suffer from the same pests and diseases. Some of these pests and diseases harm the leaves, causing them to turn yellow, which reduces the plant's photosynthesis and affects growth and development. So what diseases cause yellow leaves? How should they be controlled? Let's take a look below!

1. Leaf mold

Symptoms: Leaf mold usually starts on the lower leaves of the plant and then spreads upward. It is most severe during the fruit-swelling stage. In the early stage, light-colored irregular patches appear on the leaves, and small white mold spots appear on the underside of the leaves at the patches. The color then gradually darkens, and many growers mistake this for a nutrient deficiency or frost damage. However, in the later stage, as the damage becomes more and more severe, the entire leaf becomes covered with patches, then turns yellow and dies, seriously hindering plant growth, depriving the fruit of nutrients and reducing yield.

Control methods: Strengthen vegetable garden management. In the early stage of the disease, fungicides such as thiophanate-methyl can be sprayed for control. After each harvest, a garden cleanup should be carried out, and diseased residues, fallen leaves, flowers and fruits should be collected and taken out of the garden for disposal. Avoid continuous cropping to reduce the incidence of the disease.

2. Whitefly

Symptoms: Many growers, for convenience or to save on cultivation costs, do not put film over their greenhouses, but this actually makes later management more difficult. In hot, dry environments, whiteflies are most likely to occur, and whiteflies have extremely strong reproductive capacity, making whitefly control even more difficult. Whiteflies generally lay eggs on the underside of leaves, and after the larvae hatch they directly suck the sap from the leaves, causing the leaves to turn yellow.

Control methods: Control the humidity in the vegetable garden well, avoid drought conditions, and do a good job of disinfecting the garden to reduce insect eggs. If pests are found, insecticides such as dichlorvos or buprofezin can be sprayed to kill them.

3. Viral disease

Symptoms: Like whitefly, viral disease mainly occurs in hot, dry environments. The diseased leaves of viral disease mainly start from the top, with pale green patches appearing on the leaves, or patches of alternating light and dark green. The diseased leaves then begin to turn yellow, and in the later stage the diseased leaves directly yellow, wither and fall off, causing a very serious impact on plant growth. The spread of viral disease mainly relies on pests such as aphids.

Control methods: As just mentioned, the spread of viral disease mainly relies on pests, so we should focus on controlling aphids. For aphid control, insecticides such as trichlorfon can be used to kill them. To control viral disease, triacontanol can be used. Fallen leaves and fruits should be promptly cleared out of the orchard to reduce pathogens and lower the incidence of the disease.

The above are several diseases that cause yellow leaves on peppers. In fact, it is not only diseases that cause yellow leaves; drought and nutrient deficiency can also cause these problems in peppers. For yellowing caused by drought, water promptly and pay attention to the amount, then check which element is deficient and apply the corresponding supplement. That is all for today's introduction. This article is for reference only, and I hope it is helpful to everyone.