Instead of trying to poison your bananas, why don't you post in your area and have someone come dig up those you don't want for free. I am sure there are lots of people that would love to have a banana growing in their yard.

It may seem unorthodox, but a method that's fairly common on farms is to strike down the unwanted pseudostems with a machete, and hollow out the center to reveal the growing point. Then simply add a little bit of diesel fuel (I told you it would seem unorthodox!!) to the growing point. It will kill the stems to which you apply it, but shouldn't spread to the others. I've never actually done this, but it's said to work well.

They really aren't that tough to dig out. It might take a few hours, but not that big a deal, and the plant will uptake poison, so not good for eating. Piece of cake compared to digging out bamboo.

I wish I was closer to you, I'd come dig em up and take em for ya!
Daniella

Very easily. Inject them with 24D, the active ingredient in Ortho Weedbegone and other weed killers. I use a small syringe (1 cc). Inject about one cc of Weedbegone into the center small pups. Or in larger plants inject more. I drilled a small hole at a downward angle in larger ones and infected several cc s. Large plants will die at the root in a week or two. Smaller ones will turn brown in a few days. In inject an inch or two from the base. It is easy to control groups by working from the outside in, killing what you want and leaving the remainder. I just finished thinning mine out.