Walnut blight is caused by fungal infection and mainly damages branches. It occurs everywhere, with a general incidence of 20-30%, and a serious incidence of more than 80%, causing a large number of shoots to die, directly affecting tree growth and walnut yield and quality. Therefore, it is necessary to prevent and control in time, control the disease, promote the development of trees, increase the yield and quality, and increase the benefits.
First, the disease identifies that the leaves on the affected branches gradually turn yellow and fall off: the diseased skin layer gradually loses green, and the initial stage becomes taupe, then becomes light reddish brown to dark gray, and the cortex is dry and cracked and reveals taupe xylem. When the plaque spreads to a week around the branches, the branches die and even the whole plant dies.
Second, the cause of the disease
1. The Qingyuan Garden is not thorough. The pathogens overwinter on the dead branches. The next year, the pathogens are spread by wind, insects and rainwater. The disease begins in May and June, and the disease is in the peak from July to August.
2. Management is not in place. First, the lack of water and fertilizer, the tree is weak, the disease resistance is reduced, the incidence is high; the second is the soil compaction, the root system is poorly developed, and the absorption function is reduced; the third is the mechanical wound caused by the inadvertent operation during the management process, which is conducive to the invasion of the bacteria; Fourth, the late frost damage easily caused the young trees and twigs to infect the disease.
3, the shade in the garden, poor ventilation and light transmission, the growth of branches is weak and easy to cause disease.
Third, prevention and treatment measures
1. Completely clear the garden. In the winter, the dead branches, fallen leaves, and sick fruits in the garden are removed and burned out of the garden. The whitening of the trunk was carried out in winter with 12.5 kg of raw ash, 0.5 kg of sulphur powder, 1.5 kg of salt, 0.25 kg of vegetable oil and 50 kg of water.
2. Strengthen management. The first is to deepen the soil. When the walnuts are harvested, the soil is deep-turned before the leaves are removed, the soil is matured, the root system is promoted, and the absorption function is improved. The depth of deep-depth is 20-30 cm. The second is to apply enough fertilizer, combined with deep-turning each adult tree to apply 150-200 kg of decomposed organic fertilizer, and apply nitrogen, phosphorus and potassium compound fertilizers from June to July. The third is timely irrigation, promote the robust growth of the tree and improve disease resistance.
3. Cut off the dead branches. The diseased branches were found to be cut off in time and brought out of the garden to burn. At the same time, do a good job of summer shears, remove dense branches, pests and branches, and long branches, improve ventilation and light transmission conditions, and reduce the incidence.
4, chemical control. In June-August, use 70% thiophanate-methyl wettable powder 800-1000 times liquid or 400-500 times mancozeb wettable powder spray control, spray once every 10 days, even spray 3-4 times To the obvious control effect. At the same time, it is necessary to prevent and control rodworm pests such as the cerambycidae and the small gibberella, and prevent the bacteria from invading the pupil.
First, the disease identifies that the leaves on the affected branches gradually turn yellow and fall off: the diseased skin layer gradually loses green, and the initial stage becomes taupe, then becomes light reddish brown to dark gray, and the cortex is dry and cracked and reveals taupe xylem. When the plaque spreads to a week around the branches, the branches die and even the whole plant dies.
Second, the cause of the disease
1. The Qingyuan Garden is not thorough. The pathogens overwinter on the dead branches. The next year, the pathogens are spread by wind, insects and rainwater. The disease begins in May and June, and the disease is in the peak from July to August.
2. Management is not in place. First, the lack of water and fertilizer, the tree is weak, the disease resistance is reduced, the incidence is high; the second is the soil compaction, the root system is poorly developed, and the absorption function is reduced; the third is the mechanical wound caused by the inadvertent operation during the management process, which is conducive to the invasion of the bacteria; Fourth, the late frost damage easily caused the young trees and twigs to infect the disease.
3, the shade in the garden, poor ventilation and light transmission, the growth of branches is weak and easy to cause disease.
Third, prevention and treatment measures
1. Completely clear the garden. In the winter, the dead branches, fallen leaves, and sick fruits in the garden are removed and burned out of the garden. The whitening of the trunk was carried out in winter with 12.5 kg of raw ash, 0.5 kg of sulphur powder, 1.5 kg of salt, 0.25 kg of vegetable oil and 50 kg of water.
2. Strengthen management. The first is to deepen the soil. When the walnuts are harvested, the soil is deep-turned before the leaves are removed, the soil is matured, the root system is promoted, and the absorption function is improved. The depth of deep-depth is 20-30 cm. The second is to apply enough fertilizer, combined with deep-turning each adult tree to apply 150-200 kg of decomposed organic fertilizer, and apply nitrogen, phosphorus and potassium compound fertilizers from June to July. The third is timely irrigation, promote the robust growth of the tree and improve disease resistance.
3. Cut off the dead branches. The diseased branches were found to be cut off in time and brought out of the garden to burn. At the same time, do a good job of summer shears, remove dense branches, pests and branches, and long branches, improve ventilation and light transmission conditions, and reduce the incidence.
4, chemical control. In June-August, use 70% thiophanate-methyl wettable powder 800-1000 times liquid or 400-500 times mancozeb wettable powder spray control, spray once every 10 days, even spray 3-4 times To the obvious control effect. At the same time, it is necessary to prevent and control rodworm pests such as the cerambycidae and the small gibberella, and prevent the bacteria from invading the pupil.
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