Diseases and pests of grapes: how to recognize, cure, prevent
Even experienced growers often suffer losses in their crops caused by various diseases and pests. In order to fight them in a timely manner, it is necessary to recognize them and to know how to protect and treat grape bushes.
Diseases of grapes and their treatment
To date, more than 500 diseases of grapes are already known. Their main causes are oversaturation or lack of necessary elements in the soil for bush growth, lack of light, adverse weather conditions, as well as insects that transmit viruses. The most dangerous are untreatable viral diseases, often destroying entire vineyards.
Stains on grape leaves
Due to the attack of fungi or parasites, spots appear on the vine leaves. They come in different shapes, sizes and colors depending on the source of infection. Finding them on the leaves, you should immediately begin treatment, since these spots are a source of new infections and cause weakened immunity in the vine bushes.
The leaves are dry
Many of the diseases are also the cause of the drying of leaves in the vine processes. The insidious disease of chlorosis is the result of a large number of carbonate compounds in the soil, from which the foliage turns yellow and dries. It happens that over time the leaves grow back, but become much thinner and smaller. Grind and berries. The best preventive measure for chlorosis is the timely loosening of the soil, which improves air exchange.
Sometimes the leaves also dry out due to a lack of nitrogen in the soil. The introduction of organic fertilizers (mullein, chicken droppings) will be a salvation for diseased plants.
Yellowing and drying of the leaves is a sign of a disease, for example, chlorosis
Oidium (powdery mildew) is a dangerous and harmful disease caused by the fungus Uncinula necator Burril. Beginner growers often face this phenomenon when young shoots begin to grow poorly, and the leaves become curly and a grayish coating appears on them, similar to wood ash. Later, it covers emerging inflorescences and clusters. Over time, small berries die immediately, and large ones begin to crack and later also die off.
The best environment for the maturation of spores of harmful fungi is damp and warm weather. Grape growing in poorly ventilated places and heavily thickened plantings is more affected by oidium.
Promote better ventilation of the bushes:
- loosening the rows of the vineyard;
- timely pruning;
- pinching and breaking branches;
- Garter vines on a trellis.
When oidium is used, the preparations are Strobi, Thanos, Teovit Jet, Topaz, Horus. Dates and doses of treatment are indicated in the instructions.
Oidium infection of the vine leads to the loss of most of the crop
False powdery mildew, called mildew, is not inferior in its harmfulness to oidium. Most affected by this disease are vineyards in areas with high humidity. The fungal pathogen winters quietly in infected grape leaves, and in the spring of its zoosporangia, with the help of rain and wind, they are transferred to the emerging young leaves. In fairly damp weather and a temperature of 10 ° C, spores multiply rapidly, initially forming oily, light yellow spots on all green parts of the plant. Over time, instead of spots on the underside of the leaves, you will notice a powdery coating.
Places with spores in wet weather begin to rot, and in the heat they dry, causing the death of the affected parts. During the growing season, the fungus generates more than 10 times. Especially dangerous is its mycelium on the ovaries of berries. Cases of the death of the entire crop are possible.
Agrotechnical methods for protecting grape bushes from mildew include:
- destruction of weeds in aisles;
- mulching the soil under the bushes;
- the correct formation of the vine;
- destruction of bush infected with downy mildew;
- timely garter shoots;
- selection of disease-resistant grape varieties.
Since the fungus affects the inside of the leaves, it is practically impossible to do without treatments with systemic or contact preparations (fungicides). They are recommended to be applied comprehensively. You can use Antracol, Kurzat, Mikal, Profit Gold, Ridomil, Thanos (according to instructions).
Folk remedy for fungal diseases of grapes: a bucket of water filled with plant residues, add 250 ml of tincture of tea mushroom, insist 2-3 days. The contents are filtered, diluted with water (1: 6), the bushes are sprayed 1 time per week during the growing season.
With mildew, a white coating appears on the bottom of the leaf, and then goes on to the ovary of berries
Gray rot often affects grafted bushes, as the grafting sites and graft serving unprotected cuttings are a good target for the pathogen. In the spring, cold and dampness contribute to the awakening of the fungus. Rot is easy to spot on awakening tender buds and shoots. She later besieges annual branches and all greenery. This disease is also characterized by plaque on the underside of leaves, on inflorescences and clusters. As soon as you touch such a part of the bush, you can see a pillar of dust. In a dry climate, if the grapes are not treated with fungicides in time, the fungal infected areas darken and dry out. To prevent the disease, the same agricultural measures and preparations are used as with powdery mildew.
Gray rot turns a bunch of grapes into a mushy lump
One of the dangerous fungi that prefer high humidity and warm weather. He, like powdery mildew pathogens, hibernates in the infected areas of a grape plant.
Brownish spots on the leaves of the vine, and later on its woody parts indicate the presence of anthracnose. A vine cracked by an illness gradually dies. For preventive and therapeutic purposes, systemic and contact preparations are used: Acrobat, Antracol, Ridomil, Thanos, Horus, Bordeaux mixture.
Anthracnose causes the appearance of ulcers on the stalks of grapes
Another fungus is a lover of heat and a humid environment. The disease caused by it is also called simply the withering away of shoots, escoriosis or phomopsis.
The fungus mainly affects the leaves and fruits of grapes, but it also occurs on woody areas of the bush, forming spots of red tones on them, which later become discolored. The deep penetration of the fungus into the vine slows its growth, and over time leads to destruction and death.
With a strong defeat with black spotting of different parts of the grapes, when they are completely covered with dark fungal bodies, it is almost impossible to cure the plant. To avoid such severe cases, you should start with prevention, treating the bushes after harvesting and in the early spring after the appearance of young leaves. Systemic drugs are used the same as with other fungal diseases.
Black blotches of spotting on the grapes are the cause of the death of the crop
Pests and control of grapes
Not only diseases cause great damage to vineyards. Grapes insect pests are also a threat not only to the berries, but also to the development of the whole plant.
How to save grapes from wasps
The wasp occupies the ripening bunches of grapes in order to enjoy the juice. Insects pierce the thin skin of the fruit and leave damaged clusters after the feast, which become an excellent environment for bacteria. The peak of the wasps invasion occurs in the last month of summer. Until that time, they, on the contrary, bring only benefit by eating the larvae of butterflies and beetles.
Each winegrower has his own proven method of destroying colonies of sweet tooth. Such actions are called more effective:
- Destruction of hornet's nests in early spring before the awakening of insects. After carefully examining all the structures near the vineyard and finding a hornet’s nest, they remove it and immediately burn it. The place where it was located is treated with any insecticide to prevent re-construction of the nest. This method will not help to completely get rid of wasps, as they arrive from other neighboring sites.
- The construction of "traps" with insecticides. Any container is filled with sweet treats for uninvited guests (jam and fermented wine in a ratio of 1: 2), adding a dozen drops of any insecticide.
- Smoking wasps with a smoke bomb. It is considered less effective because it requires utmost care to avoid bites.
- If there are not many vines, the ripening bunches are covered with light breathable material, tied so that insects cannot penetrate inside. You can sew special bags. The method is time consuming, but effective.
After visiting wasps, grapes remain damaged in clusters of grapes - a source of bacterial reproduction
How to protect grapes from mice in winter
Often you hear how summer residents complain about mice, which in winter do great harm to the vine, nibbling all the buds. Poison bait near grape bushes is not the best way to fight rodents. Indeed, by this we attract them not only to the poison, but also to the vine. In addition, many have pets. In such cases, the poisoned bait is contraindicated.
Mice wintering in the vineyard do a lot of damage by nibbling the bark and buds of a plant
Some growers in shelters lay out dried branches of wormwood, tansy, and thistle. In addition to plants, essential oils, Vishnevsky ointment, naphthalene, tar are used as deterrent aromatic agents. They are impregnated with needles, sawdust, small branches and laid around the bushes. But in the fresh air, the smell quickly disappears.Recent entries In April, I process roses so that no pests encroach on my beauties
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Recently, they began to use electromagnetic and ultrasonic devices that scare away rodents. The maximum area of their action is up to 200 m2. Unlike poisoned baits, they are safe for pets and humans. The advantage is absolute soundlessness.
In order not to attract mice to the vineyard, only a surface digging of the aisles is carried out. It is recommended to do winter sheltering of grapes at a later date, when the temperature reaches –2–4 ° C, so that rodents can find an “apartment” in other places.
Do not cover the grapes with fallen leaves or straw. Trash heaps left for the winter can also become the abode of mice and their breeding ground.
Tick on grapes
On grapes parasitic leaf, felt and spider mites. It is very difficult to notice insects, since they are all almost microscopic in size.
Grape Spider Mite
Light green spider with an average body length of 0.5 mm. It is easier to notice the cobweb with which it braids the plant than the insect itself. The larvae awakening in spring, which feed on grape leaves, do the most harm. Up to one and a half hundreds of larvae from the eggs of one female intensively grow, and after 3 weeks they can reproduce themselves. During the growing season, the spider generates up to 12 times.
Light spots appear on the vine leaves, covered with a white coating. In varieties with dark-colored berries, the leaves acquire a red tint. The leaves gradually dry and crumble. As a result, the shoots do not ripen, the berries become acidic due to a decrease in the percentage of sugar. With a strong invasion of ticks, the plant can die completely.
With a spider mite, bright spots appear on the vine leaves, covered with a white coating
Felt mite (itch, phytoptus)
This arachnid insect is even smaller than its spider web counterpart (with a body length of 0.2 mm). He also lives on the underside of the leaf and feeds on the juice of leaves, and sometimes inflorescences.
The winter hibernates under the bark of old boles, at their bases, under the scales of the buds of the lower shoots. When young leaves develop, he switches to them. After its action, light pink tubercles covered with fluff appear on the upper side of the leaves. In the future, they darken and grow into a continuous mass, similar to felt fabric. Hence the name of the tick. It multiplies several times during the season.
As a result of the activity of the felt tick, tubercles covered with fluff appear on the leaves
Grape leaf mite
The smallest tick only 0.15 mm long. It damages a grape plant in the winter. In spring, leaf buds can be found to have damaged buds, which subsequently produce underdeveloped shoots with deformed leaves. Sometimes gardeners take this phenomenon for a viral infection.
To combat ticks:
- Completely burn fallen leaves, weeds, as well as seedlings infected with ticks.
- In early spring, treat the bushes with 5% lime-sulfur solution (according to instructions).
- If a tick is found, spray the plants three times (1 time per week) with Actarlik, Neoron, Omayt, Sanmayt, Talstar (according to instructions) acaricides.
- Treat the leaves with BI-58 insecticides, Fozalon (0.2% solution), Karate during the growing season.
Video: treatment of grapes with contact fungicide against tick
The shiny, sticky and stiff body of an adult insect really resembles a shield that protects it from any danger. In winter, scale insects live under the exfoliated bark of the boles. Starting in early spring, these pests weaken the vine bush, feeding on the juice of awakened shoots.
At the first detection of scabs, the bush can be treated with an aqueous solution of diesel fuel (1:20) with the addition of 100 g of laundry soap. At the same time, insects are removed with a soft brush.
Female scale insects are distinguished by their fertility. Up to 150 larvae can appear from one egg laying, which usually appears at the end of May. It is important to notice them in time before they form a carapace, and treat the bushes with contact or systemic insecticides when the larvae are more vulnerable. If this is not done, small light yellow pests spread throughout the plant, sticking to the underside of the leaves. For treatments using chemicals Fufanon, Confidor, Fastak.
Up to 150 new pests may appear from a single egg laying
- winegrowers recommend paying more attention to pruning vines, more often thin out plantings by pruning dry branches. If moss or lichen appears on the stands, they should be destroyed immediately, since these plants serve as shelters for scale insects;
- grape seedlings and cuttings before planting or inoculation are carefully examined for the presence of guards so as not to bring pests into the vineyard;
- for prophylactic purposes, they use other folk remedies against scale insects: infusions of fern, lemon peel, bitter pepper, celandine.
The tiny aphid of a banana-lemon hue, called grape phylloxera, parasitizes only on this plant. Aphid larvae do the most harm. Characteristic bloated galls on leaves, cuttings and stems - this is the accumulation of larvae. With their thin proboscis, they drink vegetable juice, destroying the cell tissue of the plant. In addition to leaf, there is a root form of the insect. She lives in the underground part of the grape bush. Her larvae feed on layering, underground fungus and vine roots.
Fertile light soil is an excellent breeding ground for aphids. She also loves to live on stony soils, but almost no phylloxera is found on heavy clay and silty soils. And in the sand its individuals practically do not take root.
With a weak defeat of the aphid vines, insecticides Actellik, Karbofos are used. Sometimes severe infection leads to the most radical measure - the destruction of all bushes and compliance with quarantine in the danger zone. Today there are many varieties resistant to grape aphids. Therefore, they are most used for stocks.
Preventive measures against phylloxera:
- selection of insect-resistant varieties (Anniversary of Moldova, Rkatsiteli, Amateur, Muscat of Bessarabia);
- the use of insecticides in the preparation of seedlings for planting;
- buried landing, removal of surface roots;
- timely processing when pests are detected.
Vine bushes heavily infected with phylloxera must be destroyed
Disease and Pest Prevention Measures
The cultivation of grapes requires care in caring for the plant, as well as the implementation of mandatory agricultural practices to protect the bushes from diseases and pests, including a number of chemical treatments.
- The first preventive step in combating diseases and pests is to acquire healthy planting material.
- Equally important is the choice of place for planting the vine. It must be light and ventilated so that good air exchange prevents the development of many diseases and the appearance of pests.
- Mandatory implementation of the rules for caring for the grape bush will simultaneously serve as preventive measures. This includes protecting plants from spring back frost (the construction of temporary shelters), installing trellis and timely tying shoots to them, proper pruning of the bush, removing weeds, loosening the soil around the stem, mulching the soil, shallow digging in the winter between rows, the destruction of heavily infected diseases and pests of plant parts.
For preventive purposes, grape bushes are treated with Topaz, Teovit Jet, Strobi at least 4 times:
- on young shoots after the formation of the fifth leaf;
- during budding;
- after flowering;
- during the formation of clusters.
It is forbidden to process grapes during flowering: delicate flowers from the action of drugs can crumble! The insects pollinating them will also suffer, and future berries will gain poison.
After the dry garter of the vine is made, it is recommended to treat the soil with a 3% solution of iron sulfate or Nitrafen. You can alternate them in a year. In order to avoid fungal spores getting on young shoots, the soil is immediately mulched.
Nitrafen is also suitable for autumn tillage, as it repels mice with its smell.
They try to conduct treatment of vines from anthracnose, mildew, oidium and other fungal diseases in a complex with the first foliar top dressings. Drugs are added to the general solution along with fertilizers.
Video: when and how to process grapes from diseases
It is possible to avoid large losses in the grape harvest due to diseases and pests if you carefully look after it, be careful and take preventive measures in time.