How to control grape black bean disease by growing grapes

Grape black bean disease, also known as scab, bird's eye disease. Commonly known as toad eyes, dragons, black spots and so on. This disease is an important disease on grape. Generally, the disease begins in mid-late April, and the peak period is from mid-May to early June, and the disease is serious in rainy season. It occurs all over Shanxi Province, especially in rainy years, poor orchard drainage, extensive management and weak trees.

Symptoms: grape leaves, ear rachis, fruit stalks, tendrils, new shoots, fruits and other young parts can be affected. Brown spots are produced in the susceptible parts, such as twisted leaves, tender shoots and tendrils, and deformed young fruits. 1. Young leaves: the disease spot occurs in the leaf spreading stage, and the disease spot appears at first, which is round and reddish brown at first, then gradually expands, becomes nearly round, the middle part of the disease spot becomes gray, the edge is dark brown, and the mesophyll in the middle of the disease spot is easy to wither and die, and the perforation is formed. after the main vein of the young leaf is infected, the leaf is deformed to atrophy and curl the disease spot on the young fruit is brown at first, and then the disease spot is enlarged and slightly sunken, and there is a gray conidium emblem in the middle. It is dark brown and surrounded by a red-purple ring like a bird's eye. two。 New tip: the disease spot is long oval, the edge purple fades to black, slightly raised, the center is gray depression, sometimes as deep as xylem or pith, cracking. The disease began at the beginning of the disease and gradually spread downward. In severe cases, the whole new plant slightly blackens and dies. After the young shoots, petioles and fruit stalks were killed, they initially showed purple-brown long oval disease spots, then blackened and sunken, and in severe cases, the disease spots were connected and the disease shoots withered. The disease generally begins to occur in mid-late April, and the peak period is from mid-May to early June, and the disease is serious in rainy season. 3. Inflorescence: after infection, light brown spots appear at first, then turn black, and when severe, the whole inflorescence or bud dries up or falls off. 4. Rachis: the disease makes the whole spikelet or part of the spikelet stunted or even withered. Pedicel disease can make the fruit dry, fall off or ossify. 5. Young fruit: after infection, brown round spots appear on the fruit surface at first, and then expand, with gray-white, sunken and upper black particles in the center. The young fruit often stops growing and is easy to fall off. If it is older, it becomes dark green, growing slowly or malformed, hard and sour, sometimes splitting from the diseased part, exposing seeds, and sometimes, even if it can mature, it often turns sour and then rotts. Disease source: belong to fungal phylum, ascomycete subphylum. , Cercospora; the sexual stage has not been found in China. The conidium disk is semi-buried in the host tissue, the conidium peduncle is short, colorless, unicellular, the size is 6.6 ~ 13.2 × 1.3 ~ 2 μ m. Conidia oval or round, five colors, single cell, slightly curved, each end has an oil ball, the size is 4.8 ~ 11.6 × 2.2 ~ 3.7 μ m. The ascomycetes were first buried in the diseased tissue, and then broke through the epidermis. All the ascomycetes were a massive irregular aspergillae composed of pseudo-parenchyma, with a layer of shell on the outside, and there were several irregular cavities in it, and one vesicle was born in each cavity. The ascus is colorless and nearly spherical, and it contains 4-8 ascospores. Ascospores are colorless, banana-shaped, with three diaphragms, the size is 15 ~ 16 × 4 ~ 4.5 μ m, the development temperature of the pathogen is 10 ~ 40 ℃, the optimum temperature is 30 ℃, and the conidia are easy to form under 24 ~ 25 ℃ and high humidity. Conidia can germinate between 10 and 40 ℃, and the optimum temperature is 24 to 25 ℃. Spores are often produced above 30 ℃. Infection cycle: the pathogen overwintered mainly by mycelium in diseased vines, diseased shoots and other tissues, but also in diseased fruits, diseased leaves and diseased leaf scars. The viability of the pathogen is very strong and can survive for as long as 3 to 5 years in the diseased tissue. New conidia were produced in 4.5 months of the second year, which were spread by wind and rain. After spore germination, the germ tube directly invades the host, causing the first infection. After invading people, the hyphae mainly spread under the epidermis. After that, a conidia disk was formed in the disease part, which broke through the epidermis, and in the case of high humidity, conidia were produced continuously for repeated infection. The short-distance transmission of germs mainly depends on Rain Water, while the long-distance transmission depends on diseased branches. The formation of conidia requires a temperature of about 25 ℃ and relatively high humidity. The temperature range of mycelial growth was 10-40 ℃, and the optimum incubation period was 30 ℃. The incubation period was generally 6-12 days. At the temperature of 24-30 ℃, the incubation period was the shortest, and the incidence of more than 30 ℃ was inhibited. New shoots and young leaves are the most susceptible to infection, and their incubation period is shorter. The bleeding of black pox disease is closely related to rainfall, atmospheric humidity and young plants, especially in spring and early summer from April to June. Rainy and humid is conducive to the formation, transmission, germination and invasion of conidia; at the same time, rainy and humid, resulting in the rapid growth of host tissue, so the disease is serious. In dry years or areas with little rain, the incidence was significantly reduced. Black bean disease can occur continuously from May to October and become a peak period after the onset of the rainy season in July. The disease first occurred in the shoots and leaves that had just been extracted from the buds. That is, the disease begins at the leaf expansion stage, and the ears and grains are damaged one after another after flowering. The condition of onset is 1. Heavy rain and high humidity are the main factors for the occurrence and prevalence of the disease, even if there are 1 or 2 small rainfall can extend into the development of the disease. On the contrary, the incidence of drought was significantly alleviated. The experimental results showed that the diseased parts of the ground or trees could not produce spores under dry conditions. Nine droughts in ten years in Shanxi Province, especially in the central and northern regions, are very serious, so black bean disease occurs slightly in general years. two。 Orchards with low-lying terrain and poor drainage tend to be more serious. Poor cultivation and management, weak tree potential, insufficient fertilizer or improper coordination, etc. will lead to diseases. In particular, no attention was paid to the health work of the orchard in winter, and a large number of diseased bodies were left in the garden, which created conditions for the pathogen to survive the winter and spread in the second year. 3. The disease resistance of grape was different in different growth stages. In general, with the increase of tissue maturity, disease resistance is also enhanced. The leaves that stop growing are almost free from infection. The disease resistance of the fruit was gradually enhanced after coloring. The epidermis of the branches faded and was basically unharmed. 4. There are great differences in disease resistance among varieties, in terms of variety susceptibility: Oriental and local varieties are susceptible, and some Western European varieties are also susceptible, but most Western European varieties and Black Sea varieties are resistant, while European and American hybrids are rarely susceptible. Among them, seriously susceptible varieties are, Jimiat, sheep's milk, longan, seedless white, Baogal. Moderately susceptible varieties are vineyard queen, rose fragrance, new rose, Italy, small red rose, etc.; slightly susceptible varieties are Sabah pearl, first-class rose, French, Jiali wine, Jimusha, etc.; resistant varieties are Tasso, you Xiangjiao, Bahe, Sebier 2003, Sabir 2007, crystal, golden queen, black tiger incense and so on. Prevention and control methods 1. There are great differences in disease resistance among grape varieties with disease resistance, so varieties with good horticultural characters and disease resistance can be selected for cultivation. two。 Elimination of disease sources combined with summer pruning, thorough removal of diseased shoots, diseased fruits and diseased leaves; removal of dead branches and leaves after winter pruning, concentrated burning, in order to reduce disease sources and reduce diseases. 3. Strengthen plant management to prevent excessive application of nitrogen fertilizer, reasonable application of phosphorus and potassium fertilizer, enhance tree potential, prevent branch vines from growing, improve resistance; reasonably adjust shelf branches to make their distribution uniform, with ventilated and transparent tree structure. 4. Disinfection of seedlings and cuttings the seedlings and nursery plots used in the new vineyard must be disinfected before planting and cutting. The agents commonly used for disinfection are: 10% ammonium sulfate solution and ferrous sulfate sulfuric acid mixture (% ferrous sulfate + 1% crude sulfuric acid), 3% copper sulfate solution, Baume 3-5 degree stone sulfur mixture, and so on. The method is as follows: soak the seedlings or cuttings in any of the above solution for 3-5 minutes, then rinse with clean water. 5. Chemical control a. Before the grape leaves are spread to the fruit is colored, the medicine is sprayed every 10 to 15 days; before flowering and 70% of the flowers are 80%, the medicine is sprayed twice. The medicament can be sprayed with 0.5% lime half-dose Bordeaux solution, 50% carbendazim wettable powder 800x solution, Dasheng MFI 4580000g 1000x liquid, 80% spray gram wettable powder 800x liquid, 5% bacteriological clear water agent 1000 times solution. b. After defoliation to before germination, Baume 3-5 degree stone sulfur mixture + 0.2-0.3% pentachlorophenol sodium (PCP) was used to eliminate the source of overwintering disease. during the growing period, 1 ∶ 0.5 ∶ 200 × 240 Bordeaux solution was sprayed before and after flowering, and then 200 times Bordeaux solution was sprayed every half a month. In the later stage of growth, 50% carbendazim 800-1000-fold solution or 50% carbendazim 1000-fold solution can be used to treat other diseases.