AusBonsai

Hey folks,

One of my PJ figs appears to be suffering from some sort of leaf/pest issue, wondering if somebody could help ID and advise on best treatment

Here's the top of the leaf Underside And a shot of the tree, which seems healthy in general Thanks in advance

Kez

I would say this is rust. Avoid wetting the leaves so as to minimise the spread of the spores. Destroy affected leaves and apply either lime sulphur or mancozeb to act as an anti fungal.

Humidity tends to cause this

Rust and fungal diseases are common on figs, especially in winter but this could possibly also be the result of scale. I think I can see a couple of raised shells in the photo? Look carefully, particularly underneath the leaves and close to the midrib for small round raised shells that the scale insects make to protect themselves.
Oil spray or a systemic like confidor will treat scale.
Neither problem will kill your tree but either can sap its health and reduce vigour.