Which diseases should be the focus of prevention and control for grapes in summer?
Which diseases should be prevented and controlled when growing grapes in summer? Please provide an introduction. The following introduces three diseases that should be intensively prevented and controlled in grapevines in summer: Downy mildew: This disease mainly occurs on grape leaves and new shoots. When it develops, yellow or brown spots appear on the leaves, and in damp conditions there is also a layer of grayish-white mold on the leaves. It generally begins to develop from mid-to-late July...
Which diseases should be prevented and controlled when growing grapes in summer? Please provide an introduction.
The following introduces three diseases that should be intensively prevented and controlled in grapevines in summer:
Downy mildew: This disease mainly occurs on grape leaves and new shoots. When it develops, yellow or brown spots appear on the leaves, and in damp conditions there is also a layer of grayish-white mold on the leaves. It generally begins to develop from mid-to-late July. Control method: In early to mid-July, spray 25% metalaxyl wettable powder at 1000 times dilution or thiram at 600-800 times dilution, once every 10-15 days.
Powdery mildew: In the early stage of this disease, brown, water-soaked lesions appear on the fruit stalk or rachis and gradually spread to the berries; on leaves, the disease mostly starts from the leaf margin, with yellow-brown lesions appearing at the leaf margin in the early stage and gradually spreading toward the center of the leaf. Control method: In early July, spray 30% compound carbendazim suspension concentrate at 500 times dilution, or 75% chlorothalonil wettable powder at 500 times dilution, once every 10 days, for a total of 4-5 sprays.
Anthracnose: It generally occurs only on grapes that are coloring or nearly ripe. In the early stage of the disease, needlehead-sized water-soaked brown round spots appear on the fruit surface, then gradually expand, the lesions become sunken, the color deepens, and in damp conditions red viscous liquid oozes out, finally becoming mummified fruit. Control method: Before the fruit colors, spray 75% chlorothalonil wettable powder at 600-800 times dilution, once every 10 days, for a total of 2-3 sprays. Stop spraying half a month before grape harvest.
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