What disease causes black spots on peach fruit? A detailed guide to prevention and control methods
What disease causes large numbers of black spots on peaches? How should it be prevented and controlled? The main symptoms of peach scab are: peach scab mainly damages the fruit, but can also attack leaves and new shoots. When the fruit is affected, dark brown round spots usually appear on the shoulder, gradually expanding to 2-3 mm, then becoming black mole-like spots,...
What disease causes large numbers of black spots on peaches? How should it be prevented and controlled?
The main symptoms of peach scab are:
Peach scab mainly damages the fruit, but can also attack leaves and new shoots. When the fruit is affected, dark brown round spots usually appear on the shoulder, gradually expanding to 2-3 mm, then becoming black mole-like spots; in severe cases the lesions merge into patches. The pathogen's spread is generally limited to the epidermal tissue. When the diseased tissue dies, the fruit continues to grow, and the lesion area often develops cracking, taking on a scab-like appearance; in severe cases it causes fruit drop. When shoots are affected, the lesions are dark green and raised, often with gummosis, and the boundary between diseased and healthy tissue is distinct. Leaf infection begins on the underside of the leaf, forming irregular angular grayish-green lesions; later the lesions dry up and fall out, forming holes, and in severe cases cause defoliation. When veins are affected, dark brown elongated lesions appear.
Prevention and control methods:
1. Along with pruning, carefully cut out diseased shoots, collect them all and burn them to reduce the source of infection;
2. Carefully carry out ditching and drainage work, lower field humidity, and promptly carry out summer care of the trees so that the canopy is well ventilated and lets light through, thereby reducing disease incidence;
3. Chemical control: in early spring at the initial stage of bud break, spray 5 degrees Baumé lime sulfur mixture; from 20 days after petal fall to late June, spray once every 10 to 15 days, using 50% carbendazim 800-fold solution, or 72% thiophanate-methyl 1000-fold solution, or 75% chlorothalonil 600-fold solution, or 10% difenoconazole 3000 to 4000-fold solution, or 50% flusilazole 8000-fold solution.
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