1- What is the Botrytis of the vine? Botrytis or gray rot in vineyard.
– Botrytis is a fungus that can attack all the green organs of the strain.
– The greater severity of gray rot is due to cluster attack, since it greatly deteriorates the quality of the grape and the characteristics of the musts.
– Moisture, rain and wind , as well as the attacks of pests that cause wounds in the organs of the vine favor the entry and development of the botrytis of the vine.
– This fungus is preserved in the form of mycelium and sclerotia during autumn – winter.
– In spring it forms conidia, which are the infecting forms for shoots, leaves and inflorescences, and also for racemes in summer.
2- What does botrytis cinerea produce? Symptoms and damage in Viticulture:
– The botrytis of the vine produces desiccated shoots, flow of flowers and dry young leaves.
– The most important damage occurs when attacking the berries after poisoning or when they begin to accumulate sugars.
– The fungus penetrates through the wounds and cracks of the berries, spreading to the neighboring grains, forming dense felts on them, which eventually wither and dry out.
Varieties with compact bunches are more sensitive to this rot.
-The botrytis in vine creates characteristic grayish pads in the shape of a rooster’s crest on the affected organs, later covering the entire berry, even emptying the content of the grains and leaving them dry.
3- How to control botrytis of the vine ?. Treatment.
3.1.- Prevention treatment and ecological botrytis vid treatment:
-Because it is a fungus, all the methods that favor ventilation will help to reduce its attack. It is suitable to use low vigorous rootstocks, wide planting frames and intense pruning that allow maximum aeration of the bunches.
-It is also convenient to restrict nitrogen fertilization and irrigation after poisoning.
-Deleafing is a very effective technique to avoid damage to the bunches.
-The removal of affected bunches is an important measure to reduce inoculum in plantations.
3.2.- Chemical treatment of gray rot or botrytis on vine:
The chemical control of gray rot is based initially on the prevention of all kinds of wounds in berries (eg those caused by powdery mildew, moths, hail …), which constitute a gateway to vine botrytis .
Chemical control of botrytis in grapes is based on the use of fungicides and can be carried out with cupric compounds if the attacks are light. The range of antibiotics available today is very wide and those active ingredients that are more respectful of the environment and that do not generate residues in the wine should always be used.
3.3.- Chemical products, active ingredients recommended for the control of botrytis.
Some of the active ingredients recommended for the control of Botrytis cinerea are: