Pay close attention to the management of corn leaf spot
Maize spot disease, also known as corn spot disease, generally causes a one-to-two-fold reduction in production, with a severe outbreak of up to 30%. This year's high temperature and continuous rainfall conditions are suitable for the occurrence and spread of corn leaf spot. Therefore, we must step up inspections. First, the symptoms of corn leaf spot can occur in the whole growth period of corn, mainly damage the leaves, leaf sheath, temporal leaves and ear can also be affected. Mostly from the lower leaves of the plant disease, spread upward and expand. Leaf lesion shape due to different varieties of resistance, there are three types: (1) irregular oval lesions, or limited by the veins showed nearly rectangular, there are more obvious purple brown or dark brown edge. This is the most common type of susceptible spot. (2) Oval or spindle-shaped lesions, the extension is not limited by the veins, the lesions are large, gray-brown or brownish, no obvious, dark edges, and sometimes appear on the lesions. It is also a disease type. (3) Small yellow-brown necrotic spots, which are not substantially enlarged, and there are obvious yellow-green halos around them, which are resistant lesions. Second, the spread of epidemic conditions germs by air, rain spread. Normal summer corn can appear lesions at the 2 to 3 leaf stage, lesions are dense at 5 to 6 leaves, and the leaves are coked, and the incubation period for the disease is short. During the growing season, more infections occur and the damage is heavier. The corn will follow the disease after harvest. The debris will continue to winter. The key to the climatic conditions in which germs occur is temperature and humidity. Based on a certain source of bacteria and susceptible species, the degree of disease is determined by the temperature and humidity. For small spot disease, if the temperature in July-August is stable for more than 25°C for a period of time, it will be heavy if it encounters more rain and more exposure. In addition, the corn crop was seriously ill and was seriously ill near the village. The incidence of straw returning was heavy. Third, the prevention and control method Because of the large area of ​​corn planting, and the widespread incidence of leaf spot disease, the onset of the epidemic, so once the epidemic, the use of local small measures to control more difficult. Therefore, we should focus on the major scope of prevention-based measures. 1. Remove diseased leaves. At the early stage of disease, when the incidence rate of the lower two leaves is about 20%, the diseased leaves should be removed immediately. The diseased leaves taken out of the field should be buried deep or burned, and 3 to 5 leaves should be removed every 7 to 10 days to control the disease. The expansion has obvious results. However, it must be carried out on a large scale, and the effect is obvious in the short term. Immediately after removing the diseased leaves, fertilize and water to promote growth and enhance resistance to disease. 2. The ploughing plan. Reduce soil moisture and improve environmental conditions in the field. 3. Increase phosphorus and potassium fertilizers, strengthen field management, and increase plant resistance to disease. 4. Chemical control. Spray 70% thiophanate-methyl wettable powder 600 times, or 25% benomyl 800 times, or 10% Segosol 2500-3000 times, or 50% carbendazim Wet powder 600 times liquid, interval 7 to 10 days 1 time, even defense 2 to 3 times. Natural, No-addition, Fig series products WEIHAI ACCELERATE BIOTECHNOLOGY CO, LTD , https://www.accelerfig.com