Corn sheath blight symptoms and control methods

How should we prevent and treat corn silk sheath blight? Today I will tell you the specific methods:

Corn sheath blight symptoms

The disease can infect the leaf sheath, leaves, cobs and bracts, first starting from the entire base of the leaf sheath and then spreading upward. In the early stage, water-soaked gray-green nearly circular lesions appear, which later turn into white, light yellow or reddish brown moire patches. When the humidity is high, white mold, i.e. hyphae and basidiospores, will form on the lesions, and later sclerotia will be produced, which are white at first and dark brown when mature.

Disease pattern

The pathogen overwinters as hyphae and sclerotia left in the soil and on diseased remains. When the temperature and humidity are suitable in the second year, hyphae grow to infect the plants and spread. The disease mainly occurs in the middle and late stages of corn growth. If it rains for a long time after jointing, the disease is serious. Fertile soil, partial nitrogen fertilizer, vigorous plant growth, low-lying terrain, poor drainage, field shade, high temperature (optimum temperature is 26-31°C), and high humidity (relative humidity above 85%) are all conducive to the disease. If the temperature is below 20°C and there is drought (relative humidity below 75%), it is not conducive to the growth of pathogen hyphae, and the pathogenicity is very weak, or even impossible to cause the disease.

Corn sheath blight control methods

① Remove diseased and damaged parts, destroy them or dig them up and bury them deeply.

② Plant disease-resistant varieties.

③ Sow seeds at the right time, increase the application of organic fertilizer, avoid excessive application of nitrogen fertilizer, pay attention to digging ditches for drainage, reduce field humidity, promote healthy growth of corn, and improve disease resistance.

④ Chemical control: spray 5% Jinggangmycin 1000 times, or 50% triadimefon emulsifiable concentrate 1000 times, or 50% carbendazim wettable powder 500 times, or 70% thiophanate-methyl wettable powder 500-800 times, or 40% sclerotium net 800 times, or 50% thiophanate-methyl wettable powder 500-800 times. When applying the pesticide, pay attention to spraying the liquid on the female ear and the stems below to achieve a higher control effect.