Control of Maize powdery mildew

In recent years, with the occurrence of maize powdery mildew, the ear has lost its edible and feeding value, so the prevention and control should be done as soon as possible.

During the whole growth period of maize, powdery mildew may occur in all the tender parts of the aboveground parts. The diseased part is tumor-like, and the size of the tumor varies according to the location of the disease. the tumor on the leaf is smaller, and the tumor on the ear or stem node can often reach fist size. When the tumor was immature, it was a mass of white and tender tissue, which was covered with a thin film. After maturity, the tumor all turned into black powder (chlamydospore), and the black powder was dispersed after the film was dried and cracked. The pathogen overwintered with chlamydospores in soil, disease residue, compost and barnyard manure, mainly transmitted by soil, and seeds could also carry bacteria. Chlamydospores spread to the plant with the wind to produce bacteria and can be repeatedly infected. High temperature and humidity, tender growth, drought, long-term continuous cropping, partial application of nitrogen fertilizer, insect pests, storm and other factors can easily lead to the disease. The disease resistance of non-hard grain varieties and varieties with thick, long and compact ear bracts were poor.

In order to control corn smut, the following measures should be taken: selecting resistant varieties; dressing seeds with 40 ml of 20% triadimefon EC per kilogram of seeds; timely deep ploughing to reduce the source of primary infection; increase potassium fertilizer, organic fertilizer should be fully mature to prevent bacteria; timely control of corn borer and other pests, reduce wounds; high temperature, humidity or dry weather for a long time, can be sprayed with Bordeaux solution of 1RL Before the diseased film was broken, it was taken out of the field and deeply buried or burned, and the wound was smeared with thin mud; the countryside was cleaned, the diseased plants and fallen leaves were reduced, and the seriously diseased fields were rotated for more than 3 years.