Powdery mildew is a fungus that belongs to the Erysiphaceae family and frequently colonizes certain plants.
Mold appears in the form of a light velvety white layer, which is what makes it immediately recognizable.
What makes powdery mildew appear and spread?
Powdery mildew spreads most easily when warm weather and high relative humidity occur together.
It usually appears in April or May, when temperatures rise and the air is still full of moisture from the wet months of March and April.
It also makes a comeback at the beginning of fall, when nights grow longer and moisture once again increases.
How to treat powdery mildew
Powdery mildew should be treated both through preventive and curative actions.
- Ensure proper air circulation in your plant beds, to avoid stagnating moisture.
Powdery mildew spreads when plants are tightly packed together…
- Remove infected portions immediately.
Burn diseased leaves and plant parts.
- Avoid overwatering.
- Eventually, spray with fungicides.
When dealing with vegetables, favor organic treatments instead of chemical ones:
- Milk. Mix ½ quart (½ liter) milk to 4½ quarts (4½ liter) water (total 5 quarts (5 liters)), spray every week until the disease is wiped out!
Powdery mildew agents are usually specific to the plant they infect: powdery mildew on grape vines will not contaminate your rose trees.
In the vegetable patch, powdery mildew often spreads on the following plants:
radishes, leek, corn, strawberry plants, zucchini, pickles, carrots, eggplants, red beets, endives, cucumbers and potatoes.