Latest Control Methods and Precautions for Wheat Sharp Eyespot
Wheat sharp eyespot can infect wheat at different growth stages. After wheat emerges, the pathogen that oversummers in the soil infects the underground stems and basal leaf sheaths of the wheat seedlings. After wheat turns green, light brown oval or diamond-shaped lesions appear on the basal leaf sheaths of the affected wheat seedlings, with a gray center and brown edges, and some lesions show slight longitudinal cracking.
After wheat enters the jointing stage, this is exactly when sharp eyespot attacks the stems, but during this period, because wheat sharp eyespot mainly occurs at the base of the plant's stems, the symptoms are hidden and easily overlooked, causing the best timing for control to be missed.
When the pathogen invades the stem from the leaf sheath, it often causes the stem wall to become necrotic and soft, with longitudinal cracking of the diseased part, and the plant loses water and dies. In windy and rainy weather, lodging occurs and causes severe yield loss. Generally, diseased fields lose about 10% of yield, and in severe cases the loss can be 30%-40%.
1. Control methods
To control wheat sharp eyespot, irrigation should be reasonable, excessive growth should be prevented, long-term excessive humidity between plants should be avoided, and weeds in the field should be removed in time. The key period for chemical control of wheat sharp eyespot is the green-up and jointing stage. Right now is the time for watering wheat fields, and it is also the time when sharp eyespot spreads with the water. If it is not controlled at this time, it will invade the first stem node of wheat after jointing and damage the stem. For chemical control, generally use 75 grams of 70% thiophanate-methyl wettable powder per mu, or spray 20-30 milliliters of 25% propiconazole emulsifiable concentrate.
2. Precautions when spraying
① Focus on spraying the stems infected by sharp eyespot.
② Use two barrels of water per mu for spraying. If there were many white heads in the wheat field last year, then the dosage must be increased to three barrels of water. Wheat sharp eyespot is generally controlled twice: the first application when the diseased plant rate reaches 20%-30%, and the second after 10-15 days.