Are my olive trees sick?
I am new to the forum so hope I am posting this question in the right place.
I have recently moved house and inherited five olive trees. I do not know the species but believe they are about 5 years old. They are about 10 feet (3 metres) tall.
I live in Botswana (southern Africa) which is a semi-arid country with low rainfall, and temperatures ranging from 113 degrees (45 celsius) in summer (rainy season) to 39 degrees (4 celsius) (with below freezing at night) winter (dry season). The soil is sandy.
We are currently in winter.
Since taking ownership of the trees in April, I have noticed an increased yellow spotting of the leaves. And last week I saw that suddenly some of the leaves have curled up into tight coils. I also noticed that some of the leaves (though not many) have black spots on the underside.
I have done some reading online but not found much. From what I have read, the spotting may be Peacock spot and the curling may be caused by wilt. However I don't want to overeact, as for all I know, it is just what happens during winter.
Does anyone please have any information or advice for me? I am thrilled by the idea of growing and processing my own olives (one of the trees did actually bear fruit this autumn) and the thought that they may be sick saddens me.
Please let me know what you think!