Using Inert Dusts to Detect, Assess and Control Varroa Mites in Honey Bee Colonies - Final Report

Disclaimer

This report was prepared by an EPA assistance agreement recipient and represents only the views of the author rather than EPA.

Objective 1 - Evaluate inert dusts for detecting Varroa mites

We examined the use of inert dusts to dislodge mites from adult honey bees for detecting Varroa mite infestations. Six inert dusts were evaluated: powdered sugar fine sugar, wheat flour, talcum powder, corn starch, and baking soda.. Powdered sugar 92.9 ± 5.5%) and talcum powder (84.0 ± 5.6%) were found to be the most effective. The results of these studies have been published in both scientific journals and extension publications.

Using the sugar-roll technique to detect Varroa mites in honey bee colonies. NebGuide G01-1430-A. http://www.ianr.unl.edu/pubs/insects/g1430.htm

Macedo, P.A. and M.D. Ellis. 2002. Using inert dusts to detect and access Varroa infestations in honey bee colonies. J. Apic. Res. 40(1-2): 3-7.

Objective 2 - Evaluate inert dusts for assessing Varroa mite infestation level

We demonstrated that the sugar-roll technique (developed in objective 1) is an effective tool for assessing Varroa infestation levels to determine if mite population reduction measures are warranted. We also established fall treatment thresholds based on sugar-roll samples. We demonstrated that .03 and .12 mites per bee are the treatment thresholds when brood is and is not present, respectively.

Using the sugar-roll technique to detect Varroa mites in honey bee colonies. NebGuide G01-1430-A. http://www.ianr.unl.edu/pubs/insects/g1430.htm

Macedo, P.A. and M.D. Ellis. 2002. Using inert dusts to detect and access Varroa infestations in honey bee colonies. J. Apic. Res. 40(1-2): 3-7.

Objective 3 - Evaluate inert dusts for controlling Varroa mites on adult bees in bulk bee cages

We developed a technique to remove Varroa mites (Varroa destructor) from adult honey bees (Apis mellifera) using powdered sugar. Our technique requires isolating a colony’s adult bee population in a detachable box prior to powdered sugar application. We designed a detachable “bee-box” that connects to the colony’s entrance and is capable of holding the adult bee population. By applying a bee repellent, Bee Go®, to a colony, we forced adult bees into the bee-box where they were subsequently dusted with 225 grams of powdered sugar. Adult honey bee populations treated in this manner dropped 76.7 ± 3.6% (n = 28) of their mites.

Aliano, N.P. and M.D. Ellis. 2005. A strategy for using powdered sugar to reduce Varroa mite populations in honey bee colonies. J. of Apic. Res. In Press.

We applied measured amounts of powdered sugar directly to honey bee brood combs containing eggs and larvae of known age groups. Twenty four hours later, we compared powdered sugar-treated brood with similarly aged cohorts of immature bees that did not receive powdered sugar. Low and high doses of powdered sugar (.03 and .06 g per 151.5 ± 1.0 cells, respectively), caused significant egg removal of 62.2 ± and 86.1 ± 5.1%, respectively, when compared to eggs that received no powdered sugar. Powdered sugar had no effect on 5-day-old larvae, but it caused a significant percentage of 8-day-old larvae to be removed when applied at the high dose. These results support the value of isolating adult bees from the brood nest for dusting to avoid brood injury.

Aliano. N.P. and M.D. Ellis. 2005. Only large amounts of powdered sugar applied directly to brood cells harms immature honey bees. J. of Apic. Res. 44(1). In Press.

Objective 4 - Compare the survival of mites recovered from adult bees with inert dusts with the survival of mites obtained from brood

We examined mite survival after recovery with inert dusts and compared it to mite survival after recovery from brood. After 24 hours, mite survival was significantly greater when mites were recovered with corn starch, powdered sugar and from brood. As there was no difference in the 24 hour survival of mites recovered with powdered sugar and mites recovered from brood, recovery with powdered sugar is a much less labor-intensive method for recovering mites for bioassays. This result will save researchers considerable time in evaluating candidate compounds for varroa control.

Macedo, P.A. and M.D. Ellis. 2002. Using inert dusts to detect and access Varroa infestations in honey bee colonies. J. Apic. Res. 40(1-2): 3-7.

Objective 5 - Extend results to state, regional and national beekeeping organizations

International

Eleventh International Congress of Beekeeping. Monterrey, Mexico. June 9-10, 2004. Uso de azúcar en polvo para la detección y estimación de poblaciones de Varroa. and Estrategias para usar azúcar en polvo para sacar el parásito Varroa de las abejas adultas.

National

American Beekeeping Federation. Jan. 15-16, 2003. Kansas City, Kansas. Using Inert Dusts to Reduce Varroa Populations.

Regional

South Dakota Beekeepers Association. Rapid City, SD. June 25-26, 2004. Strategies for Managing Varroa Mite.

Tennessee Beekeepers Association. Nashville, TN. May 22, 2004. Strategies for Reducing Varroa Populations.

Connecticut Beekeepers Association. Hartford, CT. March 21, 2004. Strategies for Reducing Varroa Populations.

Massachusetts Beekeepers Association. Leicester, MA. March 20, 2004. Strategies for Reducing Varroa Populations.

North Carolina Beekeepers Association. Elkin, North Carolina. July 17-18, 2003. Inert Dusts for Varroa Control.

Heartland Apicultural Society. Midway, Kentucky. July 11, 2003. Using Inert Dusts to Reduce Varroa Populations on Adult Bees.

Colorado State Cooperative Extension Service. Boulder, Colorado. May 18, 2003. Integrated Pest Management of Adult Bee Diseases and Parasites.

Oregon State University Beekeeping Symposium. Salem, Oregon. Nov. 1-2, 2002. Detection and Control of Varroa Mites Using Inert Dusts and Integrated Pest Management of Varroa Mites.

Nebraska Beekeepers Association. Lincoln, Nebraska. Nov. 15, 2002. Inert Dusts for Varroa Control Research at the University of Nebraska.

While not a stated objective, this research constituted the Masters Degree Thesis for Nicholas Aliano. Four acolades awarded to Nicholas Aliano and the complete thesis and literature review are included with this final report.

Aliano Awards

Aliano, N.P. and M.D. Ellis. Does Powdered Sugar Entering Brood Cells Harm Immature Honey Bees? NCB of ESA, Kansas City, KS. March 29, 2004. Awarded 1st Place, M.S. Student Poster Competition.

Aliano, N.P. and M.D. Ellis. Does powdered sugar entering brood cells harm immature honey bees? American Bee Research Conference. Jan. 8, 2004. Awarded 1st Place, Student Presentation Competition.

Aliano, N.P. and M.D. Ellis. North Central Branch of ESA. Madison, Wisconsin. March 25, 2003. Using Powdered Sugar to Reduce Varroa Populations. Awarded 1st Place, M.S. Student Paper competion.

Aliano, N.P. and M.D. Ellis. Does Powdered Sugar Entering Brood Cells Harm Immature Honey Bees? Central States Entomological Society. Lincoln, NE. April 17, 2004. Awarded 1st Place, M.S. Student Poster Competition.

Aliano M.S. Thesis

Aliano, N.P. M.S. Thesis. August 2004. An investigation of techniques for using powdered sugar dusting to reduce varroa mite populations in honey bee colonies and of brood tolerance to powdered sugar.