Question
Oak Leaf
Good Afternoon Jim,
I've just had a walk in the local fields, most of which have been recently planted with native broadleaf trees (approximately 100 acres) about 10 years ago.
When passing an oak tree I noticed red/pinkish markings on the leaves and thought initially it was ladybirds. On closer inspection I could see they were little lumps on the leaves in varying sizes. As said earlier, the trees were planted about 10 years ago and now stand approximately 5 to 6 feet high. The neighboring oak is similarly affected but the surrounding beech, rowan, elder,ash, birch etc do not appear affected.
I should add that I live in a rural area of North East Scotland and understand that if this is a problem here it does not necessarily mean you have this as a problem in your country.
My neighbor who owns the land is a very busy farmer and should this leaf embellishment be a problem, I'd much rather approach him with positive information rather than place another problem in his 'in tray'.
Attached are some photographs taken with an infected leaf.
Any help or advice will be greatly appreciated.
Best Regards,
Hamish Carr
AnswerThey are all galls caused by an insect (small wasp) The wasp lays its eggs on the surface of the leaf or twig and secretes a chemical that causes the tissue of the leaf or twig to swell and cover the egg. the egg hatches and moves on. The galls themselves will not harm the overall health of the tree although they can look bad. Leaf galls may cause the leaves to drop prematurely. There are many types of these wasps some attack the twigs and others the leaves. Control is not usually needed and has to be timed with the wasp presence and not the galls themselves. Damage is mainly cosmetic to a mature tree. Not a real problem to the health of the tree I would not worry about them.
