I would definetly do the Transplant

As far as the Problem I would try a good Flush

There is a product called Insta Green I would give that a shot very high in Nitro and provides a quick turn around

If their were bugs you would see them do you If so how about some neem oil

I would try the transplant the feet are probably not happy and the Insta Geen should turn things around for you maybe even throw a TEA into the equation

Good Luck