A disease of leaves, round or nearly round dark brown spots with concentric rings. If the humidity is high, the black mold layer will appear in the sick class. If the disease is serious, the leaves will dry up and fall off, and the ground will turn yellow. Potatoes have wide adaptability, rich nutrition and good taste. Men, women and children like to eat potatoes. Potato has a large planting area and high yield, which is the main market variety to adjust the off-season of vegetables. What are the main diseases of potato and how to prevent them?

Treatment: At the initial stage of onset, chlorothalonil, thiophanate-methyl, azoxystrobin and difenoconazole can be sprayed alternately for about 3 times, every 7 days 1 time. In the early stage of potato late blight, dark spots appeared on the leaves, the stems turned black and the leaf buds dried up. Under the condition of high humidity, a gray mold layer will appear at the junction of the back of the leaf and the diseased part on the stem, but it is not obvious when the weather is dry. At night, root irrigation or furrow application with 2500 times of 10% imidacloprid or 90% trichlorfon 1000 times of liquid can kill underground pests. Find and control ground pests in time.

The room is near. Invasion of stems and leaves are all germs, which are brown spots at first, and then become black blocks after serious. Early blight can be prevented by spraying antiviral drugs such as Rui toxin and Yi Kuaijing. Metalaxyl can be sprayed on late blight, and the juice in these two young leaves or tubers will affect the healthy growth of plants, resulting in the loss of potato yield or commodity quality. Aphids can also spread a variety of potato viruses, which is far more harmful to potato production than aphids, and often leads to the first yield reduction. Strict implementation of quarantine system, introduction from areas without quarantine pests and diseases, and selection of insect-resistant varieties and high-quality virus-free seed potatoes as far as possible are the keys to prevent potato diseases. 2. Fertilizer efficiency is in place. Fertilization is a good thing, but we can't blindly increase the amount of fertilization. Excessive fertilizer supply will directly burn potato pieces or root growth, so the probability of potato rot or rotten heart is greatly increased.