Hi I had very heavy mite loads in the middle of August, after having treated with Apistan in April. We used coumaphos in fall of 2000 & spring 2001. That fall mites were acceptable, so we went back to Apistan fall 2001 & spring 2002. It hasn't worked, so one wonders: 1) did the coumaphos not knock out resistant mites? 2) did we pick up resistant mites from other hives? 3) did environmental conditions cause this rapid build-up? We were hearing from other beekeepers that mites were heavy by the end of July so we decided to examine all our hives for mites. By the way, we do keep a dozen or so hives untreated during the season. The mite loads on these were not higher than the treated ones, so it makes for a lot of head scratching. pb