Olive Knot

[Humbug carrot]

Has anybody heard of olive knot?
The bark on our young olive trees is starting to develop knotty, warty growths ,and in some cases peeling back from the wood.
A check on line found a disease called olive knot, which looks very similar, but I can't work out if it is a problem in this country or not.
Has anybody had any experiences with this disease?

[Humbug carrot]