Control methods of wheat powdery mildew

Wheat varieties resistant to powdery mildew, such as Zhengzhou 8915, Zhongyu 4 and Yumai 9, were selected, then reasonably close planting was carried out according to the characteristics of the varieties and local conditions, and then compost or mature organic fertilizer made by enzyme bacteria was applied. In addition, drainage after rain in the south and timely drought watering in the north are also effective measures to control wheat powdery mildew.

The causes of wheat powdery mildew include:

1. Pathogen

The pathogenic bacteria in winter wheat area in spring mainly come from the local area. The spring wheat area comes not only from the local bacterial source, but also from the adjacent areas with early onset.

two。 Climate

The optimal temperature for the onset of the disease was 15-20 ℃, and the onset was slow when the temperature was lower than 10 ℃. Relative humidity greater than 70% may cause disease epidemic. In less rainy areas, the disease is serious if there is more rain in that year. In rainy areas, if there is too much rain, the disease slows down, and the surface conidia are washed away by continuous rainfall.

3. Administration and Management

Excessive nitrogen application will result in greedy green plants and serious disease. The disease is also easy to occur due to improper management, lack of water and fertilizer, dry land, weak plant growth and low disease resistance. In addition, the density is high and the disease is serious.

The symptoms of harming wheat are as follows:

1. Harmful site

The disease can damage the aboveground organs of wheat plants, but mainly leaves and leaf sheaths, and glumes and awn can also be damaged when the disease is serious.

two。 Stage characteristics

At the beginning of the disease, 1-1.5mm white spots appeared on the leaf surface, and then gradually expanded into nearly round to oval white mildew spots, and there was a layer of white powder on the surface of the mildew spots, which scattered immediately in case of external force or vibration. These powders are the mycelium and conidia of the bacteria. In the later stage, the mildew layer of the disease became grayish white to light brown, and there were small black spots the size of needles, that is, the closed capsule of the pathogen.

Generally speaking, the control of wheat powdery mildew is the combination of disease-resistant varieties, the use of chemicals and physical control.