Today I noticed there were a few tiny black dots on nearly all the leaves of my 2 banana plants . The dots are the size of a grain of sand ; some even smaller . My plants didn't have them 4-5 days ago . And I've had both plants for 2 months and I've never saw these tiny dots until now. It's hard to believe it's sigatoka considering I live in Tennessee and sigatoka is spread from South America and my plants came to me really healthy and have been like that for 2 months . Could this have come from me overfertilizing and changing soils. I just changed it with a different type of low fertilizer miracle gro potting soil, and some compost and manure with sand.
Here's a photo : https://ibb.co/nizRVm
Sidenote : I just realized the temp and humidity have been really low inside and outside for the past week so I'm now wondering how my plant could have black sigatoka if it's too cold for the fungus to spread within a weeks time