Honey bees and other pollinators face significant threats to their health in Hawai'i. These can be attributed to six major stressors:
1. Diseases: Honey bees, like all other animals, are susceptible to a number of bacterial, fungal, and viral infections. Due to our state's isolation from other land masses and strict import laws, local honey bees are not impacted by many diseases on the mainland. Confirmed honey bee pathogens in Hawai'i include:
Bacteria: American foulbrood (AFB), European foulbrood (EFB)
Fungi: Chalkbrood, Nosema
Viruses: Acute bee paralysis virus (ABPV), Chronic bee paralysis virus (CBPV), Deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), Kashmir bee virus (KBV), Lake Sinai virus 2 (LSV2), and Varroa destructur virus 1 (VDV)
2. Parasites: The Varroa destructor mite is the single most damaging stressor of honey bees in Hawai'i, though it is only present on Oahu and Big Island. These external parasites consume the fat body of honey bee larvae and pupae, weakening their immune systems and transmitting viruses. It is critical that beekeepers monitor their colonies frequently and treat as necessary to keep mite numbers low. Tropilaelaps is another genus of parasitic mite that attacks honey bees in Asia. This would be a devastating pest for the beekeeping industry, though thus far it has not yet been detected in the United States. This is one of the emerging pests monitored for in the National Honey Bee Survey. Contact Dr. Chrissy Mogren if you are interested in participating (cmogren@hawaii.edu, 808-956-6745).
In addition to parasites attacking honey bees directly, there are also what would be considered hive parasites, or pests that live inside the colony and attack larvae or stored pollen. These include small hive beetles (SHB) and wax moths. While SHB may be present in low numbers in healthy colonies, weakened colonies may be taken over, killing the colony. Wax moths are typically only observed in already weakened colonies.
3. Pesticides: Honey bees are exposed to all types of pesticides whether they are foraging in home gardens or on farms. Exposures may be topical, for example when they fly through a cloud of pesticide during application, or landing on a leaf or flower with active residues. Exposures may also be oral, meaning the bee accidentally ingested the pesticide in pollen or nectar. The chemicals used inside honey bee hives to treat damaging parasites can also be toxic to bees when applied improperly. Pesticides include herbicides, fungicides, insecticides, and acaricides, both organic and conventional. Judicious use of all pesticides is the best way to reduce nontarget impacts to bees and other organisms.
4. Agriculture: Honey bees are essential to Hawaiian agriculture, contributing an estimated $212 million annually in pollination services. However, agricultural practices can be detrimental to bees in the area. Pesticide use, weed management that removes flowering plants, or vast areas of a single crop that blooms for only a short period of time. But agriculture could also be an opportunity to benefit bees, by integrated pest and pollinator management programs, incorporating insectary plants, and providing space for apiaries.
5. Loss of forage: Urbanization, roadside weed control, and expanding monocultures are all examples of how important foraging resources may be lost across landscape types. Access to diverse, quality forage is important for honey bees to gather pollen for developing brood, and nectar to turn in to honey. Whether you are a home gardener or own a farm, providing flowering resources year-round, in addition to crop plants needing pollination, is essential to promoting pollination services and healthy bees.
6. Cultural practices: How honey bees are managed by beekeepers also plays a significant role in long-term health and colony success. Choosing Varroa resistant queens for colonies, consistently monitoring for and treating Varroa and diseases in a timely manner, moving colonies to areas with abundant forage and/or supplementing during periods of dearth, and managing for swarming are all examples of how beekeepers can proactively protect their own bees and their neighbors' bees. Choosing to NOT treat or manage colonies for Varroa WILL result in weak colonies susceptible to robbing, which spreads disease and parasites to otherwise healthy colonies.