I have some Ridomil Gold on hand, but don't believe it's got label information for bananas. It's strong stuff and I would hate to guess on the appropriate dose for a small banana.
Thanks for all of the tips/advice.
Chong, it is unclear to me why you believe the soil is colder than the ambient temperature (even before aeration), though I can understand why the aeration can provide some cooling effect. I do have a propagation mat and could stick a thermometer into the "patient" and keep it at 85F but then I'll have to move it into my shop for that and put up my grow light. I don't think my wife would go for putting the propagation mat in the bay window...it's getting pretty weird already!
Harvey