By Shazziepx
Surrey,
United Kingdom 
Hello I have two olive trees, one is tall 7ft and healthy. The other is 4ft high. They both grow in the same conditions. The smaller tree has a developed a black coating on the leaves, it looks like soot but it wont scrap off. It has some new growth but what could be damaging my little tree? Any advice would be welcome!
29 Sep, 2015
Answers
Thank you I have never sprayed it so I will give it a try. My other tree is so beautiful and has no dicolourations. I will keep you posted.Much appreciated, thanks
Sharon
29 Sep, 2015
Check first to see exactly what's there before you spray with anything...
29 Sep, 2015
Ok thanks, I will let you know the end result.
30 Sep, 2015
Previous question
Inspect beneath the leaves and on the stems - you're looking for evidence of scale infestation/insects, or aphid infestation. You may need a magnifying glass... This looks like sooty mould, which occurs in association with an infestation of either scale or aphids. Treat the plant if you find any with a suitable spray - the sooty mould should disappear on its own if you resolve the infestation problem, but it can be washed off gently with soapy water.
29 Sep, 2015