What are the control methods for corn sheath blight?

According to reports, in the southern corn planting areas, the incidence rate in normal years is about 40%, reaching 70% in severe cases, and up to 100% in individual plots or varieties; the incidence rate is even higher in seed production fields, with the plant incidence rate in normal years above 50%, and there is a trend of worsening year by year. In the corn planting areas of Yunnan, because of the high temperature and high humidity during the corn growing period, sheath blight has become the number one disease of corn.

Corn sheath blight is a fungal disease. Its harm to spring corn is mainly during the grain formation stage to the filling stage, and the disease mainly infects leaf sheaths and leaves. In central Yunnan in early to mid-August, when the temperature and humidity conditions in corn fields are suitable, the sclerotia on the soil surface begin to germinate and form hyphae, infecting the basal leaf sheaths of corn and gradually spreading upward. It seriously affects corn yield. Combining relevant reports on corn sheath blight and the actual situation of corn planting in Chuxiong Prefecture, the following control measures are proposed:

Control measures:

1. Cultivation control. Under the premise of high yield, use cultivation measures to control the occurrence and development of corn sheath blight. This is beneficial both to the balance of the ecological environment and to the growth and development of the host crop. The methods usually used are:

1.1 Select excellent disease-resistant hybrids. There are certain differences in resistance among varieties. Selecting disease-resistant or disease-tolerant varieties is the most economical and effective measure for controlling this disease;

1.2 Fertilization. Pay attention to balanced fertilization, prevent late-stage nutrient deficiency, avoid excessive application of nitrogen fertilizer, and appropriately increase potassium fertilizer;

1.3 Drainage and reasonable close planting. Pay attention to timely ditching and drainage, plant at a reasonable density, and reduce field humidity to lessen the severity of the disease.

2. Chemical control

Apply pesticides at the appropriate time for control. When the rate of diseased plants in the field reaches 3%-5%, use 5% Jinggangmycin 1000-fold solution per mu, diluted 50% Nongliling, or 50% Xiaojunling wettable powder 40 grams, and spray with 50-70 kg of water. Apply control again after 7-10 days. Before applying the pesticide, remove the diseased leaves and leaf sheaths.