Control methods and matters needing attention of wheat sheath blight

Wheat sharp eyespot can be infected at different growth stages of wheat. After wheat emergence, the pathogen that oversummers in soil infects the underground stem and leaf sheath of wheat seedling. After the wheat turns green, there are light brown oval or rhombus spots on the leaf sheath of the injured wheat seedlings, gray in the middle, brown at the edge, and some spots are slightly split.

After wheat enters jointing stage, it is the time when sharp eyespot invades the stem, but at this stage, because sharp eyespot mainly occurs at the base of the stem of the plant, the symptom is hidden, it is easy to be ignored and miss the best control opportunity.

When the pathogen invades the stem from the leaf sheath, it often causes the stem wall necrosis to soften, the diseased part to split longitudinally, the plant loses water and dies, encounters the wind and rain weather, and lodging occurs, resulting in serious yield reduction. Generally, the yield of diseased fields is about 10%, and the yield of severe ones can be reduced by 30%~40%.

1. Prevention and control methods

To control wheat sheath blight, irrigation should be reasonable, to prevent overgrowth, to avoid long-term humidity between plants, and to eliminate weeds in time. The key stage of chemical control of wheat sheath blight was the re-greening and jointing stage. Now is the time for watering the wheat field, and it is also the time for sheath blight to spread with water. If it is not controlled at this time, it will invade the first stem node of wheat after jointing and destroy the stem. Pesticide control general mu with 70% thiophanate-methyl WP 75 g, or 25% propiconazole EC 20~30 ml spray control.

2. Precautions when spraying

(1) The stems infected by sheath blight should be sprayed mainly.

② Two buckets of water should be sprayed on one mu of land. If there are more white ears in the wheat field last year, it must be increased to three barrels of water. Wheat sheath blight is usually controlled twice, the first time when the diseased plant rate reaches 20%~30%, and the second time after 10~15 days.