What’s wrong with my kafir lime tree?

[_Marley_]

Just noticed my kafir lime tree is looking a bit poorly. The leaves are dull and most have black spots. Some sort of fungus? Damage from recent frosts? If anyone could help with some remedies that would be great.

A bit sick

[Jason]

Looks like it might be sooty mould @_Marley_. See Sooty mould on lemon tree

Members like @greygardener, @Noelle and @Adam_W might like to confirm for you and suggest the best form of attack.

Jason

[Adam_W]

@_Marley_ is that appearing on top & bottom of the leaves or just that top surface?

[_Marley_]

Only on the top @Adam_W. The bottom of the leaves seem fine.