Location: Honey Bee Breeding, Genetics, and Physiology Research
Project Number: 6050-21000-016-039-A
Project Type: Cooperative Agreement
Start Date: Sep 1, 2024
End Date: Dec 31, 2027
Objective:
Honey bee health continues to decline while human populations and food security needs continue to rise, we are confronted with the glaring necessity for more hearty and healthy bees. One way to achieve this is by using a holistic approach develop tools that beekeepers can implement to address pest and pathogen-caused health problems within their own apiaries. This is best done through applying an integrated pest management (IPM) approach which uses non-chemical control techniques paired with chemical control techniques as a last resort. IPM is an effective, efficient, and sustainable way to control pest populations, and honey bee pests like the fungal parasite Ascosphaera apis currently have no empirically effective management tools in North America at all. The development of an IPM-based toolkit for beekeepers that have problems controlling A. apis in their operations is needed within the beekeeping industry and gives researchers an opportunity to explore and develop non-chemical and chemical based control methods for this pest which may also be applied to other pest species. These control methods foundationally consist of breeding resistance to the pest within honey bee populations, which is best done after the identification of traits that promote resistance or susceptibility. We anticipate building on previous work within our unit to identify if colony resistance to A. apis in field-realistic settings is an outcome of larval resistance at the individual level. This question is currently unknown, as previous work had inconsistent results—likely due to breeder variation within a honey bee population. We also propose to evaluate the efficacy of materials that bees naturally collect to address health challenges, such as propolis—a substance bees make from tree resin. Finally, we have promising preliminary evidence for chemical control of A. apis through utilization of fungicides that bees already commonly encounter during pollination events. Evaluating the affects of these fungicides on A. apis growth as well as on individual and colony-wide honey bee health is vital in developing the first chemical control option for A. apis in North America. When these studies are combined, we will have generated an IPM-based toolkit consisting of a variety of different A. apis management techniques for beekeepers to use to address outbreaks within their own honey bee operations.
Approach:
Despite previous work identifying honey bee stocks that are resistant to A. apis, there are still significant knowledge gaps in identifying A. apis resistant bees due to a combination of inconsistent results and unknown mechanisms of resistance. We propose to use a combination of laboratory and field experiments to assess, identify, and develop various A. apis prevention and treatment strategies. We will do this in three objectives by:
1. Objective1: Continuing to identify promising synthetic and natural chemical compounds that reduce or prevent the growth of Ascosphaera apis in the laboratory.
2. Objective 2: Determining what individual and collective traits make bee colonies susceptible to A.apis in the field.
3. Objective 3: Investigating the effectiveness of integrative pest management practices for chalkbrood disease.
In objective 1, we will continue evaluating the efficacy of various fungicides at different dosages to inhibit A. apis growth. The most promising fungicides will be used in laboratory setting on larvae to see if there are negative health effects associated with fungicide exposure in vitro and if these chemicals are effective against A. apis infected larvae in the laboratory. Objective 2 entails evaluating a stock of honey bees that has been inconsistently resistant to A. apis in previous studies. We will investigate if there are some sub-portions of the stock which are more resistant to A. apis in a field setting, then further determine if colony resistance to A. apis in the field can be attributed to larval resistance in laboratory settings or if the colony resistance is likely due to a different colony-level trait such as propolis use or hygienic behavior. We need to find this information out in order to determine which lines of bees to breed for A. apis resistance, as well as to make recommendations about breeding trait selection to beekeepers. Finally, objective 3 will include field studies evaluating the prevention and treatment of A. apis at the colony-level. This includes testing the most promising fungicides from objective 1 and propolis for their effectiveness as treating A. apis outbreaks in colonies. Part of objective 3 is also the technology transfer of IPM strategy evaluations to stakeholders for implementation within their own apiaries.
By addressing these three objectives, we will ultimately be able to form an Integrated Pest Management (IPM) strategy based on empirical data which consists of breeding and utilizing bees that are resistant to A. apis, applying bee-made substances such as propolis, and resorting to a chemical-based control method if necessary. This proposed work is multi-institutional and will be completed by a team with diverse-skillsets to ultimately empower beekeepers by providing them with new tools so that they can make informed and effective A. apis management decisions within their own apiaries.
