In order to prevent the emergence and development of vine disease and also protect this fruitful plant, a good knowledge of all the possible diseases of the vine is necessary; under what conditions they occur, the biology of the disease, how to apply the appropriate means of protection, etc.
Many say that grapevine powdery mildew is the most dangerous vine disease. The disease is also called a plague.
How will you identify a vine infected with this disease?
On the skin of newly-formed berries, you will notice an ash-colored gray coating that encourages the drying of berries and their cracking. This disease usually occurs in late June and early July. Given that the grapevine powdery mildew expands very rapidly, it is necessary to react promptly to prevent it in time. To control the grapevine powdery mildew, select the appropriate fungicide, such as:
– Fungicides with surface effect based on meptildinocap and sulfur
– Systemic (pyrimidines and triazoles)
– Combined fungicides
However, experts recommend the following:
– Use fungicides, systemic fungicides, up to 2 to 3 times a year
– For the first and last treatment of vines, the following fungicides should be used: dinocap, sulfur
– The frequency of treatment of vines with fungicides may also adversely affect further growth and development of vines. Therefore, up to 12 days should pass between two sprays.
– The maximum recommended concentration of fungicide should be used to treat vines
– Do not apply curative systemic fungicides
The disease does not attack only berries but also leaves, bloom and green shoots, so it is important to approach the plant treatment in time.
Another known disease of grapevine is downy mildew or peronospora. The disease attacks berries, leaves, flowers, bunches and even shoots. The first signs of illness appear on lower leaves. The most common symptoms of this disease are brown and dried infected flower caps. Then sporangiophors with sporangia appear on the bloom, which is quite noticeable because you have the impression that the entire part is coated with a white coat.
The most effective protection in the fight against this vine disease is to provide adequate conditions when growing vineyards.
The conditions for the development of infection are:
– Wet ground and temperature between 8 – 10 ° C for more than 24 hours
– Drops on leaves at least 4-6 hours, ie. constant rainfall for two days (10 mm rain)
– The existence of zoospora in the vineyard
– 4-5 cm diameter of the vineyard leaf
In the treatment of this disease, the use of “mild” organic fungicides is recommended, but copper is used in Dalmatia.
Mildew of the grape vine is also caused by fungus attacks on leaves, shoots, petioles, and berries. The mildew will is recognized as a yellowish blob that eventually becomes gray. If these leaves are exposed to water, a scratch-resistant coating will appear on the spot. Disease can cause rotting. In addition, the disease may attack the petiole even before flowering, so falling off of the whole bunch or part is inevitable.
In order to protect the grape vine from the gray mold, we recommend using less lush substrates (vineyard soils). In addition, the vineyard should be raised so that the rows of vines are directed towards the direction of the wind blowing. Relative moisture can be reduced by timely removal of sprouts, because the bunch itself is then more exposed to sunlight.