Question
HI, I have a holly tree and its leaves have developed brownish scabs in the middle of the leaves --on the top side of the leaf. leaves are going yellow and dropping pretty quickly. Please help.thanks Maggie

Answer
Hello Maggie

This sounds like a case of holly leaf miner.  If you look closely at the discoloured patches you may see 'tunnels' radiating outwards from them, where the leaf miners are eating away the tissue between the upper and lower surface of the leaves.

The cause is the larvae of the Phytomyza ilicis fly, which lays its eggs on the young foliage in early summer.  Fortunately these flies only lay one lot of eggs per year!

There is no effective control for this pest as insecticides cannot penetrate the waxy leaves of the holly, however, the damage tends to be cosmetic, as the infestation really has no impact on the vigour of the plant - holly leaf fall is not usual at this time of the year as older leaves are naturally discarded and it is probably that, rather than the leaf miner, which is causing it.

I hope this information eases your mind!

Gill