Hi Mark and all, I have been using the method of FGMO fogging described by Dr. Rodriguez. Basically, you fog every other week for about 5 seconds per hive. I'll admit I've not been doing the cords he describes at that frequency- I've been refreshing them at only once a month. A much more detailed account on this fogger business can be found at www.beesource.com . In their "digital dialog" section you will find a discussion group about FGMO. An hour spent there should answer your question much better then I can. Bee happy, Don