Last time I used it on any of my plants was Aug 3. I had just bought a new mini and it apparently came infected. I caught it early on and only one of my other orchids was affected. I'm not sure how long the stuff stays in the plants system.
...After reading what you guys posted and thinking things over more thoroughly...I think I'll be cautious and just keep on the look out. I've only been growing since Feb. so my orchids have had some ups and downs as I learn. They are doing good at the moment, and as they say, "If it ain't broke, don't fix it."
I will be very unhappy though if I do find any critters on them, the last thing they need is more stress. ...just like people. lolol