What are the common diseases of grapes? What are the prevention and control methods?

Grape is a common fruit, which is welcomed by everyone. The common diseases of grape are downy mildew, white rot, anthracnose, brown spot and so on. Let's take a look at the prevention and control methods of these common diseases.

Downy mildew

The damage to the leaves initially produced small spots with translucent, watery, unclear edges on the leaf surface, and then gradually expanded into light yellow to yellowish brown polygonal spots, with different sizes and shapes, and sometimes several disease spots were linked together to form a large yellow-brown dry disease spot. When the air is moist, the back of the lesion produces white mildew (sporophore and sporangium of the pathogen). After the disease spot is dry and brown, the diseased leaves are easy to fall off early.

Tender shoots, tendrils, petioles and flower peduncles are susceptible, the disease spot is translucent watery spot at first, then gradually enlarges, the disease spot is yellow brown to brown, slightly sunken, when the air humidity is high, sparse white mildew is produced on the disease spot, and the growth of the disease shoot stops, twists and dies seriously.

The young fruit is susceptible, the disease spot is nearly round, grayish green, there is a white mildew on the surface, then wrinkle and fall off, the fruit is susceptible after growing up, and generally does not form mildew. Ear axis is susceptible, which can cause part of the ear or the whole ear to fall off.

The pathogen overwintered in the diseased body or in the soil with fallen leaves. Wet, cool, rainy, foggy weather is serious.

Prevention and control methods:

Adhere to the principle that prevention is more important than cure: before the occurrence of the disease, especially before the rainy season, pay attention to the prevention with protective agents, such as propionate zinc, enylmorpholine, flumomorphine and so on. When the disease was serious, flunomide and aldicarb hydrochloride were sprayed twice at an interval of about 10 days.

II. White rot

White rot is the most harmful disease and causes the heaviest losses, mainly harming fruits, new shoots, leaves, etc., almost every year, with a yield reduction of 15% in general years, more than 60% in epidemic years, and even no harvest.

The onset of white rot is closely related to rainfall, if the rainy season comes early, it will be early; if the rainfall is large, then the disease will be serious; if the rainy season is long, then the disease will last for a long time. There is a peak of morbidity after every rain. Especially in case of storm or hail, it often causes a pandemic. The sooner or later, the severity of the disease is closely related to the cultivation mode, the closer the ear is from the ground, the more serious the disease is. The disease can not occur on the young fruit, but only when the fruit begins to color and mature, and the closer it is to maturity, the more serious the disease is. The pathogen overwinters on the surface and in the diseased body.

Characteristics of white rot disease:

There are brown and irregular waterlogged disease spots on the pedicel and stalk, which gradually spread to the fruit grains, resulting in browning and decay of the fruit with gray-white small grain spots on the surface and vibration, the diseased fruit and even the diseased ear are very easy to fall off, and the diseased tissue smells fishy under wet conditions.

The disease is a disease of high temperature and humidity, which is transmitted by wind and rain. It is easy to cause a pandemic in the rainy season of July and August, especially after hail or storm.

Main points of prevention and control:

Before sprouting: spray Baume 3Mel 5 degree stone sulfur mixture on the plant once.

Before flowering: spraying Propylene Zinc

After falling flowers: spray propionate zinc + tebuconazole

Regular spraying of protective agents before onset: tebuconazole and thiram

Find sporadic disease spots and spray therapeutic agents in time to eradicate: tebuconazole, thiram + Guomeifeng

III. Anthrax

Anthracnose is mainly harmful to fruits. In the epidemic year, it is easy to cause a large number of fruit rot, which results in the infection of the pathogen in the overwintering young fruit stage of diseased fruit, panicle stem and annual branch, but does not show symptoms. Mainly harms the fruit, causes the fruit soft rot to fall off the disease characteristic: the early infection, the incubation period lasts for more than 20 days, the near maturity period begins to occur, the fruit ripening period enters the peak period; the ripening period infects, the incubation period is about 4 days; the disease is serious in high temperature, high humidity and rain, fog and dew.

Main points of prevention and control:

Before sprouting: Baume 5 degree stone sulfur mixture

After falling flowers: spray Pansen zinc or thiram

Before bagging: bagging after panicle spraying with promethazine + imidamide alone.

After the young fruit is enlarged, zinc propionate and thiram pesticides are used alternately. The weather is dry every 20 days, and it rains every 10-12 days.

After coloring: spray the ear with tebuconazole. Spray 70% methyl topiramate 1000 times on the leaf. Spray 2-3 times at intervals of 10-15 days. After picking the bag, spray the ear with tebuconazole alone.

4. Brown spot

Brown spot is mainly harmful to leaves, resulting in early defoliation, which generally begins to occur after fruit setting, mostly in the leaves near the ground, gradually spreading upward, suitable conditions, multiple re-infection, extensive management, lack of fertility and plant weakness. It is mainly spread by Rain Water spatter, generally starting from the lower leaves, and gradually spreading upward, resulting in early defoliation, which is easy to occur in high temperature, high humidity and rainy season.

Main points of prevention and control:

Before onset: spray general protective agents to prevent, such as mancozeb, etc.

Sporadic plaque found: treatment with propiconazole

When the disease is serious, tebuconazole is sprayed twice at an interval of 7 days.