How to distinguish gray mold from white rot in grapes?

Botrytis is known as gray mold soft rot, and it is also an important disease of open field and greenhouse cultivation in the southern region, due to different climatic conditions, the degree of incidence varies from year to year, and the loss caused by some years is also very serious.

Symptoms: During the flowering period, it is harmful to the flower spike (corolla, peduncle), and after flowering, it is harmful to the cob, resulting in flower and fruit dropping, and the disease is less after fruit setting. However, in the late stage of fruit ripening and in the process of storage and transportation, such as low temperature and rainy conditions, it can still cause harm.

When the flower spike is damaged, the diseased part is water-soaked, gradually turns brown, rots, and finally wilts and withers, and is easy to fall off. The disease occurs during the near-ripening and storage and transportation of the fruit, and the diseased part is brownish-brown and depressed, and rapidly expands to all the fruit grains and decays, and the damaged fruit and cob are covered with a villous rat-gray mold layer. It is infected during the ripening period of the fruit, if the subsequent weather is dry, the pathogenic bacteria are latent in the fruit, the fruit surface does not show symptoms, but the peel becomes thinner, the fruit loses water and shrinks, does not rot and has high sugar content, so this phenomenon is also called "noble rot".

After the new shoots and leaves are susceptible, irregular brown lesions are produced. When the humidity is high, a gray mold layer is formed on the surface.

White rot is the most costly fruit disease in grape fruits, with losses of more than 60 percent in endemic years.

Symptoms: Damage to the cob, fruit, leaves and new shoots. At the beginning, there are brown water-stained spots on the small fruit stalk or spindle, and gradually spread to the fruit pieces.

The lesions are yellow at first, then turn brown, and when they spread to the whole fruit, they turn brown and rot. Small grayish-white dots are scattered under the skin of the diseased fruit. The diseased fruit loses water and becomes a dead fruit of pig liver color, which is easy to fall.

The disease of branches and seedlings mostly invades from wounds, and the initial appearance is water-soaked light brown lesions, and expands longitudinally into concave dark brown large spots, and the epidermis is densely covered with gray-white small grains. The lesions wrap around the branches, and the upper part of the vine dies. The lesions on the leaves are light brown, nearly round, and have inconspicuous concentric whorls, and are easy to break after drying.

From the color of the hyphae, it can be distinguished from gray-brown is gray mold, white is powdery mildew.

The symptoms of white rot are obvious, the cob and the peduncle are light brown and water-soaked, and the cortex is rotten and torn; Fruit with grayish-white mucus.

Botrytis is mainly found in sheds and storage periods, and the main feature is the gray mold layer, and there will be black sclerotia during storage; The lesions on the leaves are inverted V-shaped.

1. Definitions. Powdery mildew can occur from seedlings to heading. It mainly harms the leaves, but also the stems and ears.

It begins with white lesions and gradually changes to light brown in color, which can be self-crossed or crossed to form a black ascomycete shell. In general, there are more upper blades than upper blades, and the back of the blades is more than the front.

Whereas, downy mildew refers to a plant disease caused by downy mildew in the fungus. Downy mildew is an obligate parasite, and a very small number of downy mildew can be artificially cultivated, such as Posa digitaria which causes millet white disease, and parasitic downy mildew that causes downy mildew of cabbage.

2. Solution.

For powdery mildew, the overwintering period is sprayed or coated with a dilution of 3 to 5 degrees of stone sulfur mixture from Baumey. Note that susceptible flowers such as melon leaf chrysanthemum cannot be applied. Spray sulfur powder on the ground, generally use 25 grams to 30 grams per 70 square meters to eliminate the source of overwintering bacteria.

Downy mildew can be sprayed with 500 times of 75% chlorothalonil wettable powder at the beginning of the disease, and 500 times of 58% methyl frost and manganese-zinc wettable powder or 800 times of 69% enoyl-manganese-zinc wettable powder when the disease is severe. Spraying once every 7 days, and continuously controlling 2 or 3 times, can effectively control the spread of downy mildew. At the same time, it can be combined with spraying foliar fertilizer and plant growth regulators for control, and the effect is better.

Hello, the following measures should be taken to control grape gray mold:

1) Clean the orchard:

The sclerotia overwintering on the diseased residue is the main source of initial infection, therefore, it is necessary to combine the prevention and control of other diseases to completely clear the garden and do a good job in the prevention and control of the overwintering dormant period. After the onset of the disease in spring, the diseased flower spikes should be carefully removed and destroyed to reduce the source of reinfection.

2) Strengthen orchard management:

Control the use of fast-acting nitrogen fertilizer, prevent branch growth, inhibit vegetative growth, properly prune overgrown branches, or spray growth inhibitors, do a good job in the ventilation and light transmission of the orchard, reduce field humidity, etc., and have a better effect on preventing gray mold.

3) Timely pest control:

Pest control can reduce fruit wounds, so that gray mold is less likely to infect fruit grains.

4) Pharmaceutical prevention and control

Spray once in the spring germination period 3 5 Baumé stone sulfur mixture; Spray 1 2 times before flowering for prevention, you can choose 50% carbendazim wettable powder 500 times, 50% Herui water dispersible granules 1200 times, 70% thiophanate-methyl wettable powder 800 times, 50% promethine wettable powder 800 times, etc., but the resistance of Botrytis to a variety of chemical agents is stronger than that of other fungi. In addition, 600 times of 75% Daknin wettable powder, 400 times of 3% polyantimycin, etc., can also treat gray mold.

Grapes need a lot of nutrients, and nitrogen fertilizer is the main fertilizer in the early stage, and phosphorus and potassium fertilizer increase correspondingly after entering the fruiting period. In addition to organic fertilizer, 80-150kg of nitrogen, phosphorus and potassium are required per hectare per crop (harvest), which should be adjusted according to different varieties, yields, tree potentials and soil fertility. Basal fertilizer is applied after winter, and chicken and duck manure is applied 3

00,000kg, cake fertilizer 3750kg, superphosphate 3750kg.

Top dressing was applied before shading buds, before flowering and fruit expansion, and timely spraying of strong fruit tiling, nitrogen fertilizer was mainly used in the early stage to promote the growth of branches and flower spikes, and phosphorus and potassium fertilizers were added at the fruit expansion stage to improve quality. Foliar sprays of potassium dihydrogen phosphate can promote fruit enlargement and ripening.

To produce high-quality grapes, the vineyard needs to be irrigated to prevent drastic changes in the soil from drying and wetting. Generally, more water is required in the germination stage and the growth period of young fruits, and timely irrigation is recommended in case of drought.

Botrytis injures grape corolla, peduncle and inflorescence peduncle before and during flowering, resulting in direct loss of inflorescence grains. In addition, the harm of gray mold in the fruit coloring to maturity stage is also more serious, which can cause fruit rot. Grape leaves and shoots develop irregular light brown lesions, sometimes with gray mold.

Downy mildew is mainly harmful to the leaves, the initial stage is water-stained spots, the leaf surface is pale yellow or brown, the back of the leaf forms a white dense frost-like substance, new shoots, tendrils can also be damaged, the fruit is susceptible to infection with young fruits, the color of the susceptible fruit is like coated with lead, and the white mold layer can be seen when wet, and the fruit begins to shrink from the fruit stalk, the peel becomes brown, and the dry hangs on the fruit spike.

When powdery mildew is harmful to the leaves, the leaf surface produces irregular, greenish patches of different sizes, the mold layer formed mainly covers the leaf surface, and the fruit grains are also susceptible to infection with young fruits, the fruit surface first appears brownish-green patches, showing a reticular pattern, which is covered with a layer of white powder, although the diseased fruit is not dry, but stops growing, the flesh tastes sour, and the fruit grains are longitudinally cracked in the later stage.

Grape powdery mildew is white powdery, generally on both sides of the leaves, generally can make the leaves curl, downy mildew into gray frosty mildew layer, in the case of dryness rarely see the mold layer, the lesions are radial.

Botrytis cinerea. 10 days before flowering and 1-2 days before the first flowering is the key time for the prevention and control of pesticides, the commonly used agents are 30% Ai Miao EC 5000 times liquid, 50% Sukelin wettable powder 1000 times liquid, 50% carbendazim 800 times liquid, 50% quick-extinguishing wettable powder 2 000 4 000 times liquid, 25% 100 grams of wettable powder 1 000 times liquid, 80% Dasheng one m wettable powder 800 times liquid, Fengshou pure wettable powder 800 times liquid, 65% Kedling wettable powder 1 000 1 500 times the solution.

Grapes grown in sheds were disinfected by spraying 50% of Formais 400 times or 1 000 times of promein in combination with the prepared soil before the shed.

Prevention and control methods:

Prune carefully, cut off diseased branches, diseased fruit ears and diseased tendrils, and completely remove them outside the room (shed) to burn or bury deeply. to remove the pathogen.

Sweep the fallen leaves, and combine fertilization, and mix the fallen leaves and the top soil with fertilizer and bury them deep in the fertilization ditch.

The non-drip antifogging film is used as the outer covering material of the facility, and the ground in the facility is covered with a full-area plastic film to reduce the humidity in the room (shed), inhibit the germination of pathogen spores, and reduce infection; Increase ground temperature, promote root development, enhance tree potential, and improve resistance; Prevent residual germs in the soil from escaping into the air and reduce the incidence rate.

Pay attention to adjust the temperature and humidity in the room (shed), maintain the indoor temperature of the white angel at 32-35, control the air humidity at about 75%, maintain the temperature in the room (shed) at night at 10-15, and control the air humidity below 85%, inhibit the germination of germination of germination, slow down the growth of germs, and control the occurrence and development of diseases.

Ear bagging to eliminate the harm of pathogens to the ear.

Do not remove the canopy film in summer, (you can open the big top air outlet and bottom air outlet), so as to prevent the spread of germs through rainwater and induce the disease of branches and leaves.

Chemical control: Every 15-20 days, carefully spray 1 time of 240-200 times half of Bordeaux liquid to protect the tree. And between the two Bordeaux liquids, a high-efficiency, low-residue, non-toxic or low-toxicity biocide is sprayed.

The following pesticides can be used alternately: 50% mancozeb wettable powder 500 times, 80% spray wettable powder 800 times, 80% methyl tobuzin wettable powder 1000 times, 70% Kelu wettable powder 700-800 times, 75% chlorothalonil wettable powder 600-800 times, 50% antibacterial special wettable powder 600-800 times, 80% anthrax Fumei wettable powder 600 times, 20% silver fruit wettable powder 600 times, etc. In order to improve the control effect, when spraying non-alkaline liquid, 600 times of "Tianda 2116" or 1000 times of drought and flood harvest can be added.