mildew is a fungus that can infect the new young leaves on Prunuslaurocerasus
under humid conditions and between the temperatures of 6 to 30oC.
Rainfall or drier conditions can interrupt the spread of the disease.
Mildew will not threaten the life of the plant but may look unslightly.
white powdery coating on the leaf, particularly the underside of the leaf.
of the new leaves.
the powdery coating dies off, the leaf will have brown patches or be completely
brown and withered.
There is normally no need for
chemical control as the plants will grow through the disease once the growing
conditions change to become less humid.
the leaves look particularly unsightly, you can prune them off with a pair of
secateurs or a hedgetrimmer. Disinfect the tools before using them on other
plants. Clear up any diseased leaves to prevent re-infection and burn or
dispose of them. Do not compost them.
Potassium bicarbonate at a rate of 5 grams per litre of water sprayed until
run-off has been shown to control powdery mildew on many plants and is now used
commercially. A number of applications may be necessary.
such as Bayer Fungus Fighter should result in control of powdery mildew.
Examples of Fungicides (Myclobutanil - Neem Oil – Propiconazole
- Thiophanate-methyl )