Powdery mildew is a fungal infection, distributed by fungal spores. The fungus favours warm moist conditions to set foot onto a plant and warm dry conditions to thrive.
We can’t control the presence of fungal spores and we can’t control the weather conditions but there are some basic rules that help reducing the risk:
- always water early enough for the leaves to dry off again, water the soil, avoid wetting the leaves,
- do not overcrowd beds, make sure there is plenty of air circulation,
- avoid over-fertilising with nitrogen in warm weather conditions. It leads to leaf growth and bad air flow,
- remove some leaves and thin out plants in warm weather conditions, allow for air flow,
- wash tools and hands after dealing with fungi
- apply diluted worm juice twice per month to strengthen plants,
- once a week, apply milk-spray as a preventive measure.