Be wary of summer corn brown spot epidemics

Corn brown spot is one of the main diseases in the middle and late stages of maize. The damages include corn leaves, sheaths and stems. The lesion is round or elliptical, first occurring at the tip of the top leaf, initially pale yellow, gradually turning to yellow-brown or dark brown. In severe cases, the lesions fuse to form a large brown streak, and the epidermal rupture of the lesion at the end of the disease The leaf cell tissue is necrotic, with a brown powder, and the veins and vascular bundles remain as filamentous. Most of the lesions on the stem occur near the knot. The incidence of different corn varieties is different. Once the susceptible varieties are infested, the leaves of the whole plant quickly produce a large number of small yellow spots, and the leaves are quickly dried up.

The occurrence of corn brown spot disease is closely related to meteorological conditions. Recently, the city has many rainy weather, high temperature and high humidity in the field, which is conducive to the occurrence of corn brown spot disease, and the spread of disease speed is accelerated and the degree of occurrence is aggravated. According to the survey of pests and diseases, some brown spots in summer corn fields in Tongzhou, Fangshan, Daxing and other districts were seriously affected. The general disease rate was about 10% , and the highest disease rate was 90% .

In view of the recent climate suitable for corn disease, the plant and animal protection departments of all districts and counties should do a good job in monitoring and preventing and controlling diseases such as brown spot, large spot, and sheath blight of corn, and delay the spread of disease epidemics.

First, strengthen cultivation management, eliminate water accumulation in the field as soon as possible, reduce the humidity in the field, timely carry out cultivating, topdressing, weeding and weeding, promote the robust growth of plants and improve disease resistance.

The second is chemical control, which can be controlled by spray of triazolone 20% emulsifiable concentrate 1000-1500 times, or flusilazole 40% emulsifiable concentrate 8000 times. When spraying, foliar fertilizer can be added appropriately.

Source: Beijing Suburb Daily