How to combat gray mold in a biological way
The biological fight against Botrytis cinerea, or gray mold or botrytis, starts from a correct ecological agro condition between the plant we want to grow and its ecosystem. Errors of planting, variety choice and choice of area can be so incisive as to nullify any subsequent possibility of containing this mushroom.
The Botrytis cinerea is an aerobic parasitic fungus, it is polyphagous, being able to affect different plants, especially the vine, attacking mainly the fruits, but sometimes also shoots and leaves.
As said, the first fight is the indirect one; that is, the choice of agronomic conditions and techniques that diminish the virulence of gray mold.
Among these measures a good strategy can be the reduction of the strain vigor and a management of the green to increase the optimal aeration of the bunch of clusters. But the first choices are pre-implantation and aimed at reducing the vegetative vigor; among these: varieties more suitable according to the type of soil; position and exposure; choice of form of breeding; sixth of plant; rootstock and clone that allow the plant vigor to be more easily contained. In addition to the plant design phase, then, some practices will have to be implemented including: significant reduction of nitrogen input in fertilization, and permanent or seasonal grassing with control in the row in order to create competition for water and elements nutrients and facilitate the balanced development of vegetation. Furthermore, for a good control of the gray mold, it is important to remember the correct management of the opaque foliage with appropriate toppings and with early and moderate peeling of the cluster area.
Among the innovative methods of biological control we remember instead the use of the spores of the fungus Ulocladium oudemansii that, when it is distributed on the vegetation, colonizes and aggressively occupy the space occupied by gray mold, entering into physical competition with it until it succumbs. These spores are sprayed at the beginning of the flowering phase (approximately 5% of this) and when the flowering has almost completely occurred (about 90%) with doses related to the commercial formulations present. These treatments can be repeated in case of massive attacks of botrytis in the phases of growth of the berries and in prechiusura of the bunch.
We still remember the use of zeolite and the use of microorganisms such as Bacillus subtilis, Bacillus amyloliquefaciens, Aureobasidium pullulans, and Pythium oligandrum. Their use is recommended both in integrated defense strategies as well as in biological ones. Finally, among the products that act by contact we remember the sodium bicarbonate and, better still, that of potassium.
Remember, however, that the constant presence of gray mold on your plants is the symptom of an error in the agro-ecological setting of your crop and your plant.