The classic symptoms
The fungal spores overwinter in a mycelium within the vines. From spring onwards, they lurk here for suitable weather conditions to spread. Warm, humid summer weather with cool nights and warm days is particularly convenient for the parasites, because the dew on the leaves promotes germination. These symptoms can be used to identify the infection:
- in the first stage, a gray-white coating spreads over all green parts of the plant
- both the lower and upper sides of the sheet are affected
- the leaf veins turn dark and the leaves fall off
- the grapes, which are still green, are covered with a floury, white patina
- in the further course the grapes burst open and rot
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In the case of continuous rain, the infestation pressure decreases, because mildew grapevines depend on changing weather conditions.
Combat white deposits on grapes biologically
At an early stage of the infestation, the chances are good that mildew to counteract grapes with natural means. Among the home remedies, soda has been shown to be quite effective. To do this, dissolve 1 heaped tablespoon of soda in 2 liters of water and add 15 milliliters of curd soap or vegetable oil. Fill this mixture into a hand sprayer and treat the infected grapes every 2-3 days.
In addition, milk has proven itself to be an excellent means of killing the fungal spores. Dissolved in water at a ratio of 1: 5, spray the mixture on repeatedly. Alternatively, add 3 sachets of baking powder and 4 tablespoons of vegetable oil to 5 liters of water. After every downpour, the treatment is refreshed until no white coating is visible any more.
Preventive measures
These measures make a valuable contribution to prevent the unsavory white mushroom lawn from occurring in the first place:
- an education system that is as airy as possible
- Avoidance of nitrogen-stressed fertilization
- more careful Pruning in February and green waste in summer
- consistent control of weeds
- targeted choice more resistant Grape varieties
Tips & Tricks
Experienced hobby gardeners ensure that the active ingredient is changed in good time when using biological fungicides. The oidium fungal spores and all other conspecifics have the ability to develop resistance to natural pesticides. Consistent anti-resistance management counteracts this.
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