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Rosemary
The leaves on my holly tree are covered in a black powder.

The leaves and branches on my holly tree are covered with a black powder which can be carefully removed with cloth after spraying with white oil, although this is a very tedious job. After removing the black powder the leaves are a lovely deep green colour and there are lots of red berries on it,I don't know if it's a pest or a disease. Any help would be gratefully appreciated.
Many thanks....

Submitted: 08:25PM, 01 May 2012
Answer: Hi Rosemary,
The black powder on the leaves is called sooty mould. It is normally produced when an insect pest is present such as scale or mealy bug. As the insect feeds it excretes a sugary substance on which the mould grows. Once the insect pest is treated then the mould no longer develops.

Inspect the branches and stems for scale. Apply Pest oil and ensure good coverage of the pests. Apply a second application 10 days later. The best time to treat for scale is in Spring when the scale are quite small.

Category: General
Tags: scale, Holly
Answered: 03:20PM, 07 May 2012

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