NCDC210: A Regional Effort to Maintain the Health and Survival of the Honey Bee, the Most Important Pollinator.
Statement of Issues and JustificationHoney bees are the most important pollinating insect in North America. The value of the increased crop yield and quality achieved by honey bees is estimated at $14.6 billion (Morse and Calderone, 2000). The value of commercial crops directly pollinated by bees (almonds, apples, cranberries, alfalfa and vegetable seed, etc.) is estimated at $5.8 billion annually. Nearly $9 billion worth of agricultural goods indirectly benefit from pollinating bees (e.g., alfalfa hay, meat, and milk). In addition, honey bees make a significant contribution to enhancing the environment by pollinating wildflowers, home gardens and ornamentals (Buchmann and Nabham, 1996), which is difficult to assess a monetary value.
Two parasitic mite pests of honey bees were introduced into the US: the tracheal mite, Acarapis woodi, in 1984; and the varroa mite, Varroa destructor, in 1987. These mites have had a devastating effect on honey bee colonies and beekeeping businesses throughout the US. Control measures for the mites have dramatically increased operating costs for beekeepers. Feral colonies (living in trees and abandoned structures) have been virtually eliminated by the mites, placing enormous pressure on the beekeeping industry to cope with the challenges of pollination and honey production. With the reduction of feral colonies, more growers throughout the nation are seeking out beekeepers to transport managed colonies into their fields and orchards. However, mites and economic pressures on beekeepers have resulted in a decline in national honey bee colony counts from an 4.3 million in 1985 to 2.5 million in 2005 (National Agriculture Statistics Service, 2005).
To control tracheal and varroa mites, beekeepers use in-hive pesticides and other compounds. Tracheal mite infestations are reduced by applications of menthol crystals within the hive, however, menthol has limited effectiveness in cold climates. Resistant bee stocks are becoming available for controlling tracheal mites. Since 1990, one product has been registered to control Varroa mites, a synthetic pyrethroid, fluvalinate (Apistan®). Mite populations became resistant to fluvalinate in Italy (Lodesani et al. 1995), and in 1997, fluvalinate resistance was discovered in the United States (Baxter et al, 1998; Elzen et al, 1998, 2000). A second pesticide, the organophosphate coumaphos (Check Mite +®) recently received Section 18 (emergency) registration status for use in cases where the mites are resistant to fluvalinate. In some states, mites are also beginning to show resistance to this pesticide (Spreafico et al, 2001). In-hive use of these pesticides could contaminate honey, beeswax, and pollen. It is therefore highly urgent to develop an integrated and sustainable approach to mite control through education of beekeepers and research on alternative methods.
Recently, another problem emerged. The most virulent bee brood disease is American foulbrood, caused by the bacterium Paenibacillus larvae. The disease leaves highly infectious, long-lived spores in the combs in the hive. For the last 50 years, this disease has been controlled by the use of one antibiotic, Terramycin. However, in 1996 and 1997, strains of bacteria were found in the Upper Midwest that were not inhibited by the antibiotic. The extent of the problem is not yet known, but if not contained, colony mortality could be severe.
Nosema disease, a disease caused by a protozoan unicellular parasite, Nosema apis, also causes many problems in beekeeping, especially in cold and humid regions as is typical of the North Central region. Nosema infection decrease worker longevity, decrease their nursing ability so queen quality and worker larvae suffer, causes queens to be superceded early, and colonies with high spore loads show dysentery during winter and often die before spring (Wang and Moeller 1969, 1970; Pickard and El-Shemy, 1989). Survival colonies also are weak and cannot provide adequate pollination or produce a good honey crop as healthy colonies (Fries, 1993). An antibiotic, Fumidil, has been used since 1950s. There is the fear that Nosema might become resistant and as a result causing more damages to beekeeping in the North Central region. Studying the epidemiology and mode of action of this parasite on honey bees will give us insights for its control.
It is critical to maintain the vitality of honey bees and of the beekeeping industry in the North Central Region. This region contains the 3rd, 4rth, and 5th largest honey producing states. Furthermore, special problems in survival of honey bee colonies during cold winters are unique to this region. Beekeepers typically operate on narrow profit margins and are leaving the business at a time when needs for pollination have increased due to the loss of feral colonies. Regional coordination is needed in research and extension efforts in this area.
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