Hello James, So nice of you to say those nice things about my writings, I appreciate them Since colony death or severe illness caused by Varroa infection usually occurs in mid summer rather than in the spring, this is the time that worker bee brood is tapering off and the Varroa mite population is increasing dramatically. The IPM approach is to lower that mite population before it has a chance to get well under way, and this means removing mites BEFORE they are turned loose in the colony. Several researchers have deemed that a colony functions at its peak when it has a late spring drone population as high as 20% of the bee population. This sounds very high to me, but the researchers and scientists seem in agreement on the 20% figure. This suggests using 4 frames of drone foundation out of 20 brood frames to meet this 20% figure. I am suggesting using only 1 or 2 frames out of 20 brood box frames, because I don't want to "waste my queen's energy and time" producing drones rather than needed workers. Further, the female mite enters the bee larva cell on the 8th day since the egg was laid (one day prior to capping of the larval cell, and then the female mite lays one male mite egg on the 12th day, a female mite egg on the 13th day, and maybe a 2nd and even a 3rd female mite egg of subsequent days. The male mite mates and dies, but the female mite eggs feed on the bee pupa and emerge with the drone bee. The drone gestation period is a full 24 days, so it is suggested that you install a drone cell frame for 23 days, remove and freeze it, install a replacement frame of drone cells, and repeat. None of this procedure is "caste in stone" in directions. However, one MUST BE COGNIZANT of the overriding principle behind IPM, and that is do not make an attempt to kill (or remove) all of the Varroa or even 70-80% because that will over stress the bees; but only do that which is necessary to reduce the Varroa population to a point that the bees can function in a healthy environment and live with some minor percentage of Varroa in their midst at all times. I guess it is sort of like washing your hands with Ivory soap before you eat; which is NOT LIKE a surgeon scrubbing his hands before he operates. I am an OLD retired scientist, and I guess that "retired" entitles me to try 10% drone foundation in my brood chamber instead of 20% and I will find out whether that is enough or too little. I hope I have helped. BTW, isn't it about time for the heather nectar flow? I had hoped to make a 7th trip back to Scotland to bring back memories of my ancestry, but my age of 80 plus the devilish 5 strokes that I have suffered over the past 11 years will keep me in the states. I wanted to visit Glenlivet distillery on the River Spey again and visit the Isle of Skye and maybe pick up a tartan. George Imirie