Diseases of grapes - description with photos
In this article, you will learn about what diseases of grapes exist (brown spots, powdery mildew, chlorosis, Alternaria and others) and on methods of dealing with them.
Every gardener who grows grapes on his site wants to get a bountiful and rich harvest of these beautiful berries. But, unfortunately, sometimes it turns out that the plant begins to hurt, and may even die. To avoid this, you need to know what diseases the grape bushes can be susceptible to and how to deal with them.
Diseases of grapes - description with photos
Mildew
This disease in the common people is called "downy mildew". A very dangerous disease, because in a short time it can ruin even the largest grape plantation.
The first sign of the disease is the appearance of light yellow spots on the leaves, about 1 cm in size. On adult leaves, they are parallel to the veins. If you do not fight the disease, then the light yellow spots will turn into a white fluffy coating on the back of the leaf.
In warm (from +20 to +27) and humid weather, the fungus develops and spreads very actively and quickly, absorbing the entire grape bush and nearby plants as well.
Downy mildew is most active during periods:
1.From May 20 to June 13.
2.From June 23rd to June 30th.
3.From July 15 to August 7.
How to prevent the appearance of mildew?
1. Choose the right site, which is in a well-lit place.
2. Mulch the soil and hit the weeds regularly.
3. Excess shoots must be removed.
4. Use drip or drainage irrigation.
5. Feed the plants with fertilizers.
6. Timely process the grapes with special protective compounds.
Alternaria
The disease appears due to high humidity. The second name for Alternaria is olive spot.
The first sign of the disease is the presence of gray-olive spots on the back of the leaf. Further, they completely curl up and dry up.
The infection attacks not only the green mass of the grapes, but also the fruits. They crack and taste very unpleasant.
How to prevent the appearance of Alternaria?
1. Feed your grapes regularly.
2. Mulch the soil.
3. If you find infected leaves, remove them immediately.
4. Weed the grapes in time and cut off dry leaves and branches.
5. Treat the plants with special protective compounds.
Processing time.
1. Copper processing (March 21 - April 25).
2. Treatment with biofungicide (April 24 - May 9).
3. Processing with "Quadris" (May 16 - June 1) is carried out every 2 weeks before the start of fruit formation.
4. Pruning grapes (August 15 - September 1).
5. Copper tillage (October 20 - November 10).
Chlorosis
The infection attacks those plants that lack iron. In infected bushes, the leaves are covered with bright lemon spots, and soon disappear. The fruits do not ripen.
To prevent chlorosis, use Chelate.
Oidium
A winter-hardy infection that attacks the entire plant. Fungal spores are carried by the wind. The infection develops most actively at a temperature of +20 degrees Celsius.
Infected leaves are covered with white bloom on the outer and inner sides of the leaf, and bent from the edge. Berries and flowers are also covered with a bloom, it resembles flour, and dark spots appear on the shoots. This is the characteristic of this grape disease.
How to prevent the appearance of powdery mildew?
1. Feed your plants regularly.
2. Prune dry, frail, non-fruiting branches.
3. Dig up the soil.
4. Get rid of weeds.
5. Water the grapes gently, strictly to the root. You cannot get on the foliage.
6.Treat shrubs with special protective compounds.
Cercosporosis
The fungus develops at elevated temperatures and humidity and affects the entire plant, from the roots to the fruits.
At a temperature of +40 degrees Celsius, the fungus ceases to develop, and it also disappears when exposed to sunlight.
An olive-colored bloom appears on the infected leaves, and soon it turns into brown spots. The berries are also covered with bloom, harden, and fall off when touched. If infection occurs, cut and burn diseased leaves and branches, treat diseased shrubs with fungicides.
How to prevent the appearance of cercospora?
1. Remove weeds regularly.
2. Dig up the soil in the spring and fall.
3. Feed the grapes.
4. Prune dry and diseased branches twice a season.
5. Spray the grapes with a special protective solution.
Rubella leaf
The infection intensifies from late spring to early summer. Yellow spots appear on the leaves of white grapes, and bright red spots appear in dark varieties. Diseased leaves fall off before flowering.
How to avoid rubella?
1. Dig up the soil between the rows of grapes.
2. Feed your plants regularly.
3. Treat the bushes with special protective compounds.
4. Prune away weak, dry branches and branches that do not bear fruit.
Aspergillus rot
The disease attacks grapes and develops actively at temperatures of +30 degrees Celsius and above. If the disease is not prevented in time (do not remove the infected berries), then it will quickly spread to the clusters of the entire plant.
At the first stage of the disease, the berries are covered with a white bloom, soon dark brown spots appear, on which the skin cracks.
How to prevent Aspergillus rot?
1. Harvest on time, without letting ripe bunches hang for a very long time.
2. Get rid of already infected berries.
Armillariasis
The infection manifests itself in the form of a fungus that affects the roots of grapes, killing the living cells of the plant, which leads to its death.
Most often, armillariasis forms in the spring, survives the winter, and in the fall, the yellow mushrooms that cover the plant turn.
A favorable environment for the development of the disease is humid and warm (+15 - +20 degrees Celsius) weather.
If one grape bush is sick, it is necessary to dig it up together with the roots as soon as possible and treat the ground with a special solution. Otherwise, all other shrubs will be infected.
Septoriasis
Small brown spots appear on infested leaves. With high humidity, the back of the sheet becomes covered with mold, which dries up and falls off, which leads to the spread of the fungus. This is the characteristic of this grape disease.
If you notice that the grapes are infected, immediately remove all fallen and diseased leaves and branches.
To prevent septoria, treat the grapes with special solutions.
Escorioz
The fungus affects all plants as a whole. Cool weather with a high level of humidity is most favorable for him.
On damaged bushes, it is necessary to cut off diseased branches, and then treat them with a special compound that contains copper.
How can you prevent escoriasis?
1. Regularly apply fertilizers that contain boron and zinc to the soil.
2. Timely prune the bushes.
3. Remove infected branches from shrubs and be sure to burn them.
Coping with grape diseases is not difficult, the main thing is to recognize the disease in time and start fighting it.