Even fruits consecrated by Greek gods, and grapes are just such, are not immune from diseases that can destroy the entire vineyard. The purpose of this article is to help gardeners correctly recognize grape diseases. Rapid, accurate identification of diseases is the key to preventing serious crop losses..
- Bacterial cancer
- Bacterial wilting
- Anthracnose or black spot of grapes
- Black rot
- Grape treatment from diseases
The severity of diseases of vineyards varies from year to year, depending, first of all, on the weather conditions and susceptibility of the vines. This means that the disease can lead to devastating consequences in one year and insignificant in the next. Therefore, the measures that are taken to prevent losses may differ from season to season.
In the fight against pests and diseases of grapes a considerable number of preparations are allowed to use. Often excessive infatuation with some of them leads to a loss of sensitivity of pests to the means of protection used and to the inhibition of the growth processes of the plant itself.
In order to economically and environmentally justifiably carry out protective measures, it is necessary first of all to conduct phytosanitary examination of plantations taking into account the development phases of the vine.
The first examination is carried out during the swelling of the kidneys, then when there are 2-5 leaves on the green shoot, then - before the flowering of the grapes. The survey should be started already in early spring, especially on uncontaminated vineyards.
If the site consists of several bushes of grapes, then each plant is examined. Determine the maximum manifestation of the identified species of pests, and the first 1 to 2 pesticide treatments are carried out throughout the site in accordance with the results of the survey. In the future, if possible, individual approach to each variety, taking into account its susceptibility to specific pests.
In the vineyards of farmers and specialized farms, not only each variety is subject to inspection, but all areas that differ in location and duration of protective measures in the previous vegetation. Large tracts on the plain usually pass diagonally and examine 5-10% of the bushes of grapes. On sites located on the slopes, in forest belts or water bodies, it is necessary to examine the plantations at the top and bottom points, in well-ventilated and not purged places. At each site, the minimum and maximum manifestations of diseases and the number of pests are recorded.
The first early spring examination of grapes is carried out on the following objects: bacterial cancer, bacterial wilt, anthracnose, black spot and oidium.↑ to the contents ↑.
This disease is most often found on the stem, less often on the fruit links. On the grapes and sleeves are available
longitudinal cracks, and they can easily see the tumor. The surface of the swelling is uneven, bumpy, with small cracks. The lesion sites can be from 10 to 30 cm in length. Most often, swellings are located closer to the ground, sometimes there are huge influxes on the stems. Such tumors by spring die, dry up, and they can easily be separated from the bush.
If the bulge encircles the stem, then such a bush will die in the next 2-3 years. Shrubs, located at a distance of 3-5 meters from the patient, should be attributed to patients with bacterial cancer, even if there are no external signs of manifestation of the disease..
This is a quarantine disease. Long-term and annual vines appear longitudinal cracks without a tumor.
Lower eyes on the vine are underdeveloped or died. Symptoms of bacterial wilt are more pronounced at the beginning of the growing season in the years with a cold and wet spring.
In diseased bushes, the kidneys do not develop at the base of the annual shoot. At the ends of the vine, a later awakening of the kidneys occurs and weakened green shoots with short internodes and small chlorotic leaves develop. Long stems are formed on the petioles of the leaves. Part of the shoots, reaching a length of 10-15 cm, begins to dry up.
The desiccation spreads from the bottom upwards, reddish-brown cracks are formed, beginning with the second-third interstice. This leads to brittleness of shoots. The tips of the leaves acquire a reddish-brown color, and at high humidity of the air a light yellow bacterial exudate appears on them. During this period, the probability of infection of healthy bushes from patients is greatest..
Anthracnose or black spot of grapes
This disease manifests itself on the annual vine with depressed spots (ulcers) with a dark (brown, dark-violet, black) border in the form of a roller. Sometimes wounds of conducting vessels can be clearly seen in the wounds. Strongly affected shoots seem burned, and with deep wounds around the bead, the shoot is discolored. Anthracnose is a serious disease of cultivated and wild grapes. The most destructive manifests itself in warm, humid seasons..
If the brown-black spots on the leaves of the grapes increase, become gray, convex or red borders, then your vines are infected with a black spot, also known as anthracnose. Called the fungus Elsinoe ampelina. The disease also leads to the formation of dark spots on the stems and berries.↑ back to content ↑
Black spots on the vine may also be a symptom of a fungal infection, which is commonly called black rot. It is caused by Guignardia bidwellii fungus. As the disease progresses, small black dots turn into spots. Tiny dark inclusions are fungal growths. And large ones are areas of dying plant tissue, which eventually turn into holes.↑ back to content ↑
Another name for this disease is powdery mildew. Fungal disease - the causative agent - a fungus of the species Vitis. On the one-year-old vine, first a light whitish film appears, which eventually appears as brown spots of different shapes. Mushroom spores tend to spread rapidly in damp, cool conditions.↑ back to content ↑
Grape treatment from diseases
After the survey, they plan to conduct the first (one or two) sprayings of grapes against a complex of diseases. If the vine is clean, characteristic for the color variety, there are no tumors and ocellus deaths insignificant (5-15%); such plantations are not sprayed until the appearance of the third or fifth leaf on the shoot.
When vineyards are affected by anthracnose or black spotting, the first treatment with a fungicide should be performed during the bud swelling period. For this, one can use from contact medications, % Abiga-Peak, 1-3% Bordeaux liquid% poliram; from the number of system-contact % Mikal 5% Ridomil Gold,% Ordan.
In vineyards affected by bacterial cancer or bacterial necrosis, copper-containing fungicides should be preferred (Abiga-Peak, Bordeaux fluid, Cuproxat, Ordan, Cichom). In addition, during the sap movement, the pruning of bushes should not be carried out, and in the growing season - to limit the excessive use of nitrogen fertilizers.
In vineyards, strongly affected by oidium, the first treatment is expediently carried out in phase 1 - 3 leaves on the shoot with one of the preparations 3% Topaz 2% Strobi % Thiovit Jet or Cumulus.
In vineyards affected by black spot and oidium, the best treatment option for swelling buds is, % Mikal, in the phase of 2-5 leaves - a mixture of two preparations for simultaneous containment of oidium and black spot, anthracnose.
In vineyards, oppressed by the root form of phylloxera, along with protection against seasonal diseases, a complex of measures is required against root rot..
In private farms on grapes of the mentioned fungicides are allowed Abiga-Peak, Kuprikol, Kumulus, Tjovit Jet and Topaz.