What are these tiny black dots ? Is this sigatoka ?
 

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

Re: What are these tiny black dots ? Is this sigatoka ?
 

I'm no expert, but I really don't see a problem there considering the growing conditions.

Re: What are these tiny black dots ? Is this sigatoka ?
 

Likely insect damage.

Re: What are these tiny black dots ? Is this sigatoka ?
 

You're right . The growth rate decreased a bit after I caused a leaf to burn because of too much fertilizer but it's starting to grow at its original pace now that the fertilizer dissipated, I repotted it in new soil and went back to watering it frequently. I also don't think it's sigatoka since there are no black spots under the bottom of the left . It could be due to me leaving them outside in 35-40 degree cold weather the past few days and them not getting enough sunlight