Since about 1990, two mite species have been cause for concern among both professional and hobby beekeepers in Texas. The Varroa mite, Varroa jacobsoni, is the most serious mite problem for Texas beekeepers. Varroa mite parasitizes adult drone and worker bees by attaching to the outside of the bees’ bodies and feeding on hemolymph (blood). This can lead to severe weakening and/or destruction of colonies. It may take 2-3 years for an infested colony to develop obvious signs of infestation. Varroa mites appear to be established throughout the state.
Tracheal mite, Acarapsis woodi, is an internal parasite of honey bees. The mites infest the tracheal system in the first segment of the thorax of the honey bee. Lifespans of infested bees are shortened by tracheal mite infestations. Severely infested bees are unable to fly, and large numbers of bees may be seen crawling on the ground near the hive. Diseased bees will often drop to the ground from the alighting board, or while flying, and may be seen gathered in small clusters near the hive. Tracheal mite infestations are reported less commonly in Texas than Varroa mite infestations.
Detecting Mite Infestations
Tracheal mites are extremely small and require a dissecting microscope and special clearing techniques to detect. Varroa mites are large enough to be seen on the body of an adult bee. They appear somewhat like a brown tortoise attached to the back of the bee, or on developing brood. Several methods are available to detect varroa mite infestations. For one description, see the publication on varroa mites by Virginia Tech University.
Varroa mites can be controlled effectively with fluvalinate insecticide sold to beekeepers under the tradename Apistan™. Once mites are detected in a hive, all hives in the area should be treated. Because mites also inhabit sealed brood, treatments are most effective during late fall to early spring, when numbers of brood are low. The Apistan™ label requires that treatments be limited to times of year when honey is not being produced. December to January is the best time for Varroa mite treatment in Texas.
Extender patties, a long-time treatment for foulbrood disease, have also been shown to provide control of Tracheal mites. Recipes for making these patties from vegetable shortening, table sugar, and an antibiotic, terramycin, can be obtained from beekeeping associations or beekeeping supply houses.
Tracheal mites may be treated with menthol. Menthol is a white crystalline organic compound used in perfumes, in cigarettes, as a mild topical anesthetic, and as a mint flavoring. When placed in small quantities in hives, it effectively fumigates the colony, killing tracheal mites. Beekeepers can obtain any of these materials from most beekeeping supply houses including Dadant’s (217-847-3324) and Walter Kelley (800-233-2899).
For More Information
For more information about these and other disease-causing agents of bees, contact your local beekeeping association. For further information about honey bee swarms and controlling bees, see Texas Agricultural Extension Service publication E-346, Honey Bees in and Around Buildings. General information about Africanized honey bees from the U.S. Department of Agriculture, see the website at http://www.ars.usda.gov/Research/docs.htm?docid=11059. For general information about insects, or help with additional questions about bees or other pest problems, contact your county Extension office.
Michael Merchant, Ph.D., Professor and Extension Urban Entomologist, Texas AgriLife Extension Service