Larry Garret uses the powdered sugar shaker method to count mites. The method works well for his smaller number of colonies at each apiary and the tools are very easy to transport and store. Although there may be a slight difference in the actual counts provided via sugar shaker from those provided via alcohol wash the key is that the method and counts are consistently reproduced for comparison, he says. Above is a picture with his tools, below a result.
After each “shake” he writes the results on the back of the hive. The photo below shows a “hive log” of 2.3% mite infestation on 4 October with an oxalic acid dribble on 1 November.
Randy Oliver tells us: The alcohol wash methods have the drawback of killing the bees, and possibly the queen if you’re not sharp eyed. Paula Macedo and Marion Ellis came up with a bee-friendly jar test (Macedo & Ellis 2001). Set up a jar as for alcohol wash, with a 1/8” screened lid. Shake in 300 bees from the broodnest, put on the lid, and sift 1 rounded tsp of powdered sugar through the lid onto the bees. Roll the jar until the bees are all white, then let them sit for a minute. After one minute, invert the jar over a white surface (or better yet, a white pan of water so wind doesn’t blow the mites away), and shake the sugar and mites out for a full minute (continue if mites keep falling). Macedo recovered about 80-90% of the mites; in my own tests, we recovered about 65-70%. The bees can be returned to the hive unhappy but unharmed. http://scientificbeekeeping.com/fighting-varroa-reconnaissance-mite-sampling/
Hello Erik,
last week Antonio Nanetti , an Italian beekeeping professor and leading expert in varroa research ,came to our beekeeping association to show us the result of his last work on sugar dusting.
Unfortunately he says that the method is not reliable due to umidity and temperature variations during dusting. He also says that checking only on 300 bees the sample is not significative respect to the whole colony. The only valid system is to dribble oxalic acid on the whole family and wait 48 hours to count the mites on the bottom board
Regards
Marco Moretti
Dusting colonies with powdered sugar as a means of Varroa control is different from the powdered sugar shake used for mite sampling. The monthly powdered sugar shake for mite sampling, weather permitting, done consistently allows me to monitor and track mite infestations to make management decisions.