I have a sweet bullnose pepper that I brought in during the winter. It's in a south-facing picture window. We had a crop of small peppers in December. It started flowering again in early January, but I nipped all the buds. (I thought there was too little daylight - I live in S. Ontario.) It's now flowering very generously again.

The problem: some kind of disease. It's in none of my books, and I can't find anything about it online.

The bottom sides of many of the leaves have small raised spots (some whitish) and a whitish shiny rust alone the inner vein. The leaves dry out at the rust. They get a generally puckered look and feel stiffer than they should be. The new leaves seem shorter and rounder than they should be.

It's not powdery like powdery mildew, and it's not sunken or bullseye marks like viruses.

I've looked at the leaves under a handheld microscope, and I don't see any movement, so I don't think it's bugs or worm. I've sprayed it with an antifungal twice, and then recently with a copper powder, but I can't tell if that's doing anything. I'm also wondering if the leave problems are just a reaction to cool drafts coming off the window.

I have photos, but I'm not sure how to upload them here.

Does anyone else have experience overwintering peppers? Or have an idea what this disease might be? Thanks.