Pest or disease on lemon tree

joneso192

Hi, so IV owned a lemon tree for about 5 years, it's lived in the greenhouse for 2-3. Every year a dirty sediment appears on the leaves, at first I thought it was normal, but after wiping the leaves and cutting off bad ones, it returned within a few months. Can anyone identify the problem? This dirt only appears on the top of the leaves, but I almost lost the tree as last year it was so bad. Now spring is on the horizon and it's back. 

I have noticed pests on the underside of the leaf, almost like limpets. Could this be the problem?

Obelixx

The black stuff is sooty mould growing on honeydew secreted by soft scale insects.   Both are a symptom of poor growing conditions.  You could try washing off all the sooty mould deposits but the insects will be hard to shift so the mould will reappear.

Have a read of this info from the RHS and then decide whether to treat the problem or replace the plant but do make sure the greenhouse has a thorough clean either way - https://www.rhs.org.uk/advice/profile?pid=788 

joneso192

Obelixx said:

The black stuff is sooty mould growing on honeydew secreted by soft scale insects.   Both are a symptom of poor growing conditions.  You could try washing off all the sooty mould deposits but the insects will be hard to shift so the mould will reappear.

Have a read of this info from the RHS and then decide whether to treat the problem or replace the plant but do make sure the greenhouse has a thorough clean either way - https://www.rhs.org.uk/advice/profile?pid=788 

Thanks friend, that's a great help 🙂