I love micromoths too. we’ve got a micromoth called Zealandopterix zonodoxa its so cute and even has little mandibles that it can eat with. I love them so much.

Glad to be helpful :)

Bananas do and will loose their bottom leaves as they grow, so no surprises there.

As you probably know the black flaky stuff on the outside is normal sap, not mildew. As far as u can see there is only mildew present where the frond meats the trunk.

As there is only a small amount of mildew and no signs of rot I don’t think the mildew caused the leaf falling off (rather just natural growth). If it gets more chronic mildew it may cause issues in the future. We grow our bannanas outside and powdery mildew between old fronds is a given, and not a concern, however indoor plants are a lot more prone to disease so it may be a worry.

P.s. its not powdery mildew (mildew is white/grey). Its probably just some kinda mold that settled in the crack left by the leaf falling off. I would only be concerned if it is present between young fronds or starts rotting the trunk.

Sorry for getting that wrong, I’ll update it to say parasitic rather than carnivorous. Looks like it might be that species. thank you! Will check on it tomorrow to see how its developed

Yep, the only exception I can think of is if its a ladybird, cos then I find the opposite to be true