I tried 4 treatments at 5 day intervals and monitored the mite drop before and after each successive treatment, attempting to estimate the original and surviving mite population. In several hives the pattern of mite decline was close to what one would predict but in others, usually the strongest hives, mite numbers continued higher than expected and in one hive much higher. I'm pretty certain this was down to fresh mites being brought in from elsewhere.

Obviously this can be a problem with any treatment but just how many OA (sublimation) treatments are the bees likely to tolerate? Subjectively, there was little or no excess mortality amongst adult bees but there did seem to be an effect on open brood. I ended up using the last of the warm weather to treat the hives with high mite numbers with thymol, which rather defeated the object but made the hives less friendly to incomers over the long treatment period.

Sublimation seems excellent for Winter / early Spring / broodless treatment but is possibly less convincing when the bees need it most, despite the undoubtedly good mite kill. Incoming mites might throw a spanner in the works.

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html