Symptoms: It mainly harms young green tissues such as new shoots, young leaves and young fruits of grapes. When the new shoots, vines, petioles, veins, tendrils and fruit stalks are damaged, they are dark and irregularly depressed. The lesions can form ulcers with synthetic tablets, and the upper part is dead. The young leaves are damaged in a polygonal shape, and the veins are stopped to grow, causing the leaves to shrink and deform. The leaves are damaged by pale yellow round spots, the center is grayish white, the edges are dark brown or purple, and the perforations are broken when dry. The young fruit is damaged, with brown round spots, purple brown on the outside, and the center is grayish white like a bird's eye. In the later stage, the lesion is cracked, and the disease is small and sour.
The law of onset: The pathogens mainly overwinter with hyphae in diseased leaves and diseased branches. After the germination in the next year, new sub-convived stalks are produced, which are spread by wind and rain. When the conditions are suitable, the spores germinate and invade from the natural pores such as lenticels and stomata. After infection, the lesions can form after about 10 days. And repeated infections, resulting in aggravation of the disease. Long-distance transmission relies on diseased seedlings and cuttings. The temperature at which the sub-cannon is produced and invaded is 25 °C. The Shanghai area can form the first infestation during the sprouting stage. After 10 days, the lesions begin to appear in the base of the new shoots, 1-3 leaves, and the first peak occurs 15 days later. In the future, the infection will continue to be repeated. In May and June, the mid-to-late period is the peak period. At this time, the rainy season is not only rainy, the humidity is high, and the temperature has risen to about 25 °C, while the new shoots, branches and leaves. The fruit is in a young stage and is beneficial to the invasion of germs. From July to August, due to high temperature and heat, low humidity, combined with tissue aging, the incidence of pathogen infection was inhibited, and the incidence was less. After the end of August, when the autumn is cool and rainy, it will spread again, and the suppression will continue until the leaves fall. Eurasian varieties and local varieties are susceptible to disease, while American varieties, such as rose dew, are more resistant to disease.
Control methods (l) Clearing the garden in winter to reduce the source of initial infiltration. (2) Bamei 3-5 degree stone sulphur mixture evenly sprayed branches; (3) At the beginning of the leaf (two leaves and one heart, the new shoots are about 5 cm in length), the control begins, and the spraying is carried out every 2 weeks. Two leaves and one heart period, 1-2 days before flowering, 80% Xiehua and 10 days after flowering are the four key periods of textile, and can not be ignored. The best effective agents are: 3000 times higher than Shigao, 5000 times Amishida, Bordeaux mixture (1:1: 160-200), chlorothalonil 1000 times, mancozeb 1000 times, and methyl thiophanate 1000 times. , carbendazim 1000 times and so on. It has been reported that 5% WP800-1000 times of 5% WP800-1000 times before and after flowering and early expansion of young fruit also have good control effect.
Grape black pox prevention and treatment technology
Black pox, also known as bird eye disease and sore disease, is the most widespread and most harmful grape disease in China. In the southern provinces of China, the rainy and humid weather in spring and summer is particularly serious.
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