As many of you have heard, oxalic acid has been approved by the EPA for varroa mite control on honey bees. In the June issue of Bee Culture magazine, Jennifer Berry wrote an excellent article on the subject, which I suggest you read. See: http://www.beeculture.com/oxalic-acid-effective-easy-on-bees-but/.
Oxalic acid is an organic acid, a naturally occurring chemical found in plants and insects. It has been used for some time in both in Europe and in Canada as a varroa mite control. Since traces of oxalic acid are found naturally in honey, residues are not a concern. It is commonly sold for use as a bleach in woodworking, so is easily obtainable. The registration process for a pesticide, which is what oxalic acid is when used to control mites, is complicated. Continue reading
A number of years ago, a method of non-lethal testing for varroa mites on honey bees was developed at the University of Nebraska by entomology professor Dr. Marion Ellis and some of his students. It involved the use of powder sugar in a dust application. They found that when honey bees infested with varroa mites are dusted with a coating of powdered sugar, many of the mites fall off – perhaps as a result of increased grooming by the bees, or maybe because the sugar makes it more difficult for the mites to maintain their grip. Various substances could be used instead, but powdered sugar works well, is cheap and readily available, and is easy for the bees to clean off.
The powdered sugar roll, as it is called, has become a common technique for estimating varroa numbers from a sample of bees. Continue reading
I’ve been receiving emails from beekeepers asking about media reports concerning a fly that is attacking honey bees. These media reports are the result of recently published research from San Francisco State University. This research actually began in 2008 when Biology Professor John Hafernik picked up some dead honey bees from underneath lights outside his biology building at San Francisco State. He wasn’t really interested in the bees; he was just looking for some food for a praying mantis that he had found on a recent field trip. (Praying mantises, as you probably know, are carnivorous and feed on a variety of insects.) He left the dead bees sealed in a small bottle in his lab, and was surprised a few days later to find fly pupae along with the dead bees. These pupae were identified as Apocephalus borealis, a species of parasitic fly that commonly lays its eggs inside an insect host – usually bumble bees. This finding was the beginning of a trail that would lead to the discovery of a new honey bee parasite. Continue reading