Honeybee update
Zachary Huang
Entomology

Honey bees continue to be plagued by a number of pests and diseases. Varroa mites (Varroa destructor) continue to be the worst pest of honeybees and cause high mortalities during fall and winter. The mites are largely resistant to Apistan (a pyrethroid), which has been used for more than a decade. They are also starting to become resistant against CheckMite+" (an organophosphate), registered as a Section 18 (emergency registration) in most states including Michigan for the last six years. Api Life Var (http://www.cdpr.ca.gov/docs/sec18/pdf/06-04.html) has become available (also Section 18) for varroa treatment since 2003. Api Life Var is composed mainly of Thymol and a few other essential oils, and its efficacy against the mites varies from 70% to over 90%, depending on weather conditions. Apiguard (http://www.vita-europe.com/products/apiguard.htm ) is very simlilar to Api Life Var, with its main ingredient as Thymol and has a federal registration (Section 3) since spring of 2006.

However, anticipating a shortage of this drug, Michigan has applied also for a Section 18 for Api Life Var. Formic acid is also registered as Section 8 with the trade name "Miteaway" (http://www.miteaway.com/) from Brushy Mountain bee supply. We encourage beekeepers to rotate pesticides (CheckMite+, Api Life Var/Apiguard, Formic acid) as well as combining with other integrated pest management (IPM) tactics (such as screened bottom boards, drone brood trapping of mites, etc) to delay the onset of resistance development in mites. Using IPM will also help reduce residual chemical levels in honeybee colonies. Alternative treatments such as a fungus that attacks Varroa and the Mitezapper (http://www.mitezapper.com) are still in development. The right for exclusive production for Mitezapper is recently being considered to be purchased by a developer in Detroit, and the final agreement for purchase is expected to be signed soon. I am working closely with the developer to bring the product to the market as soon as possible (optimistic estimate: spring of 2007).

Another beekeeping concern is American Foulbrood, a bacterial disease on bee larvae that can also kill colonies. The pathogen (Paenibacillus larvae) for this disease has largely become resistant to Terramycin (Oxytetracycline) but a new drug, tylosin (trade name Tylan) is already approved for honey bee use as a Section 3 drug: http://www.fda.gov/cvm/CVM_Updates/honeybee.htm

The small hive beetle, a recently introduced pest from Africa, is also present in Michigan, but so far does not cause large damages if it is controlled in the honey houses. I have seen beetles in a few colonies in the fall of 2005, so I think this pest is now established in Michigan.

Michigan currently (2006) has 65,000 bee colonies, a large drop from the 97,000 in 1997, mainly due to more complicated management schemes to control the varroa mite. Pollination so far has not been affected because a large number of pollinating colonies come into Michigan from the southern States. In California, however, pollination price went up to $150 per hive last year due to a national average winter kill of 50%. For spring of 2006, I checked a few almond growers in the Fresno valley and the prices ranged from $130 to $160 per colony. Expect to pay anywhere from $40 to $70 per hive here in Michigan, depending on the crop and colony strength.