Raw rot

Raw rot , also called sour rot , occurs on the berries of unripe grapes when Botrytis cinerea , also called gray mold , grows on them.

The raw rot is favored by warm, humid weather with a must weight below about 60 degrees Öchsle or 12 ° KMW . It also often occurs when the berries have been injured by hail, sourworms, or other causes. If botrytis infestation occurs in ripe grapes, the result is called noble rot , which can be a desired process.

The mold penetrates the berry skin with its enzymes . The skin of the berries turns brown. Some time later, a brown fungal lawn of the botrytis fungus also develops. The must of these berries is sour, unripe and intensely colored. This is where the name sour rot comes from . In the case of long-lasting rainfalls, the berries are washed out and thus there is massive loss of quantity and quality due to the loss of extracts and sugar. In extreme cases, the entire read can fail .

When the fungus attacks the grape stalks, stem rot occurs and the berries fall off. These are then referred to as soil grapes . When they are processed, they must be processed separately from the rest of the grapes. A fining can eliminate off-flavors. Most of the companies do not process these grapes.

Measures to prevent or prevent raw rot are:

• moderate foliage work in the grape zone to promote ventilation of the grapes (quick drying).
• preventive use of pesticides against botrytis.