What are the control methods for sunflower head rot?
How do you control head rot when growing sunflowers? Please introduce the methods. The harm of sunflower head rot: symptoms and conditions of onset. This disease can occur from emergence to maturity. When the stem is affected, it is mostly at the base, forming water-soaked lesions. When humidity is high, white mycelium grows on the lesions, making the stalks fragile and easy to break, and finally the whole plant dies. ...
How do you control head rot when growing sunflowers? Please introduce the methodsThe harm of sunflower head rot:
Symptoms and conditions of onset. This disease can occur from emergence to maturity. When the stem is affected, it is mostly at the base, forming water-soaked lesions. When humidity is high, white mycelium grows on the lesions, making the stalks fragile and easy to break, and finally the whole plant dies.
The flower head is susceptible to this disease at the end of flowering. When it occurs, brown water-soaked lesions appear on the back of the flower head. In rainy weather it spreads rapidly, penetrates the flower head, and grows white mycelium, causing the entire flower head to become soft and rot and fall off. The sclerotia fall to the ground and overwinter. The disease is generally severe under conditions of moist soil, low temperature and continuous cropping.
Control methods for sunflower head rot:
1. Practice crop rotation. Do not rotate with leguminous or solanaceous crops; rotation with gramineous crops is acceptable. Keep a certain distance between the planting plot and the previous sunflower field.
2. Select disease-resistant varieties and increase the application of phosphorus and potassium fertilizers to improve disease resistance. Sow late at the appropriate time, moving the sowing date to late May, so that the flowering period avoids the rainy season. Deep plowing can bury sclerotia below 7 cm of soil, reducing the occurrence of head rot.
3. Remove diseased plants from the field. During the growth period, pull out diseased plants and burn them or bury them deep in the soil; after harvest, pick out diseased plant residues from the field and burn them.
4. Seed treatment: soak seeds in 60°C hot water for 10-20 minutes, or treat seeds with 50% dimethachlon at 0.5% of seed weight. Spray during the flowering period with 50% dimethachlon 500-fold solution, or 50% procymidone or 50% vinclozolin 800-1000-fold solution, spraying 2-3 times consecutively in the late full-bloom stage, once every 7 days.
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