i had to chemically burn a sugar apples tree to the stump to kill them all- she came back but it was a two year ordeal...if i even find one on an orchid im going to incinerate it and move on....
i agree with the above for the new orchid process- i try to keep them aside and apart for a little while just in case something odd reveals itself
i try to do a really good inspection before i purchase anything to avoid issues at home.