A Detailed Guide to the 5 Common Diseases in Grape Growing and Their Control Methods

The grape is a woody vine of the genus Vitis in the family Vitaceae, native to western Asia, and is now cultivated throughout the world. During grape growing, the main common diseases include black spot disease, powdery mildew, and mealybug, among others. Below, let us look at Grape Growing: A Detailed Guide to the 5 Common Diseases and Their Control Methods!

1. Grape anthracnose

Grape anthracnose can generally invade and cause disease from June, with the peak period of disease occurring from July to August. As the fruit approaches maturity, the disease gradually worsens. Around August 10, because large numbers of fruit ripen, the disease enters its peak period whenever there is muggy, thundery rain.

Control methods: Thoroughly remove diseased clusters, diseased canes and diseased leaves, etc., to reduce the source of inoculum. In areas south of the Yangtze River, bagging can be carried out immediately after petal fall; strengthen cultivation management, promptly train the vines, tie the canes and pinch out the tips so that the trellis surface is well ventilated, increase the application of phosphorus and potassium fertilizers, and control the amount of nitrogen fertilizer.

2. Grape white rot

The disease is severe in seasons with high temperature, high humidity and much rain, and a peak of disease appears after rain. In the north, it can occur from June through the harvest period, with more disease during the fruit coloring stage and a peak after storms. The disease is severe near the ground and under conditions of heavy, sticky soil, low-lying terrain and poor drainage. It is prone to occur where weeds grow densely, branches and leaves are crowded, or humidity is high, and vigorous and leggy plants are also prone to the disease.

Control methods: Thoroughly remove diseased canes, diseased clusters and diseased leaves; train the vines in time, raise the fruiting position, weed promptly, pay attention to drainage, and strictly prohibit the application of nitrogen fertilizer before flowering to leggy plants.

3. Grape downy mildew

This disease is likely to break out on a large scale in autumn when there is much rain, much dew and low temperatures. Poor ventilation in the orchard, high humidity and excessive nitrogen fertilizer favor the disease. In the north it can generally occur from June, with the peak period from August to September. In areas south of the Yangtze River, there are 2 to 3 disease peaks throughout the year: the first during the plum rain season, the second in mid-to-late August, and in some years another peak from mid-September to early October.

Control methods: Clear away fallen leaves and diseased branches, burying or burning them; promptly pinch out tips, train the vines, drain water and weed, and increase the application of phosphorus and potassium fertilizers; spraying should begin at the early stage of the disease, generally starting in early to mid-June in the north, with spraying once every 15 days; in areas south of the Yangtze River, before early autumn, spraying can in principle be combined with control of black spot disease, and before the disease occurs, Bordeaux mixture gives the best control effect.

4. Grape black spot disease

The pathogen of grape black spot disease overwinters as mycelium in the canker lesions of diseased shoots, and can also overwinter in diseased fruit and disease scars. In May of the following year it produces conidia, which spread by wind and rain to cause primary infection. Long-distance spread is mainly through seedlings and cuttings. After the grapes bud in spring, the disease can occur continuously until September.

Control methods: In combination with summer pruning or throughout the entire growing season, thoroughly prune out diseased shoots and remove diseased fruit and diseased leaves. After autumn pruning, thoroughly clean up dead branches and fallen leaves, burn them in a centralized manner and then bury them deeply, so as to reduce the source of inoculum to the greatest extent. Reasonably increase the application of potassium fertilizer to prevent leggy growth of the plants, strengthen the tree vigor and improve disease resistance. The trellis surface should be arranged reasonably to maintain good ventilation and light transmission conditions.

5. Grape powdery mildew

The pathogen of grape powdery mildew overwinters as mycelium on the affected tissues or inside bud scales. In spring of the following year it produces conidia, which spread by wind to the host surface. The mycelium produces haustoria that extend directly into the host cells to absorb nutrients, while the mycelium spreads over the host surface. The fruit surface, canes and leaf surface appear dark brown, mainly affected by the haustoria. The disease can generally occur from early to mid-July through September to October.

Control methods: Strengthen cultivation management, increase the application of organic fertilizers, strengthen tree vigor and improve disease resistance; promptly pinch out tips, thin out overly dense branches and leaves and tie the canes, keeping ventilation and light transmission good; pay attention to orchard hygiene, remove diseased residues, burn them in a centralized manner or bury them deeply, and reduce the source of disease.

The above is Tutuliu.com's introduction to the five common grape diseases. As long as you pay attention to controlling the temperature and humidity of the orchard and plant at a reasonable density during cultivation and management, the probability of disease will be much lower.