Powdery mildew is one of the most stubborn fungal diseases that can attack the hydrangea. While powdery mildew is a fair-weather fungus, downy mildew spreads explosively in humid weather conditions.

Recognizing and distinguishing between powdery and downy mildew

powdery mildew:

  • the upper side of the leaf is always affected
  • wipeable, white to dirty brown covering
  • Leaves turn brown and dry up

Wrong mildew:

  • Fungal growth always on the underside of the leaf
  • gray or grey-violet coating
  • Upper side of leaf shows yellowish brightening
  • Leaf is slowly dying

You can only prevent downy mildew, which attacks hydrangeas more frequently. Keep the leaves dry by always watering the hydrangea from below. Algae-based plant strengtheners, which you can obtain from specialist retailers, can effectively prevent an infestation.

control of powdery mildew

  • Remove all diseased parts of the plant and dispose of them with household waste.
  • For downy mildew, spray with copper-based fungicides. Make sure that the underside of the leaves are wetted.
  • Powdery mildew is combated with products containing sulfur.
  • Treat the hydrangea several times as mildew is very stubborn.

tips and tricks

This fungal infestation can also be combated biologically. The lecithin contained in fresh whole milk or whey fights the fungus and can prevent further spread.

Category:

Vegetable garden