Source: USDA-ARS, GENETICS AND PRECISION AGRICULTURE UNIT submitted to NRP
NO MORE MUMMIES: NOVEL AND INTEGRATIVE TREATMENT OPTIONS FOR ASCOSPHAERA APIS IN HONEY BEES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
ACTIVE
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1032073
Grant No.
2024-67013-42303
Cumulative Award Amt.
$749,891.00
Proposal No.
2023-08428
Multistate No.
(N/A)
Project Start Date
Sep 1, 2024
Project End Date
Aug 31, 2027
Grant Year
2024
Program Code
[A1113]- Pollinator Health: Research and Application
Recipient Organization
USDA-ARS, GENETICS AND PRECISION AGRICULTURE UNIT
810 HIGHWAY 12 EAST
MISSISSIPPI STATE,MS 39762
Performing Department
(N/A)
Non Technical Summary
Non-Technical SummaryThere are currently no integrated pest management (IPM) strategies for A. apis infections, or chalkbrood, which are rooted in scientific evidence. Extension agents and apiary inspectors do not have science-based strategies to recommend when beekeepers encounter chalkbrood in their operations. This makes it difficult for beekeepers to effectively address disease outbreaks within their own apiaries, thus leading to frustration, economic loss, and colony death. The results from our proposed work will allow us to communicate chalkbrood IPM strategies which are quantifiably effective in preventing and treating chalkbrood. By forming a variety of IPM strategies, we are following best management practices for sustainable and responsible disease management within our crop system and ultimately generating a holistic toolkit for our beekeeping stakeholders.A. apis, although a global honey bee parasite, is currently understudied in the U.S. which gives us ample knowledge gaps to fill. Understanding what makes some groups in a single honey bee population more resistant than others is scientifically valuable and has wide applicability to other diseases and pests within social insects. A. apis surprisingly seems to have few consistent responses globally, which may indicate differential virulence of different strains or variance in responses of different honey bees populations. Our work would both fill several knowledge gaps as well as generate promising areas of future study, such as seeing if different strains of A. apis are equally susceptible to our treatment methods, and identifying molecular mechanisms associated with social immunity behaviors in response to A. apis infection.Additionally, by incorporating future and current career scientists into this project, we are helping to both generate scientific and stakeholder-centered information, as well as training future peers to communicate their findings widely which is important to STEM and to society. We ultimately propose a thorough dissemination of the knowledge through both scientifically peer-reviewed and stakeholder-centered avenues, putting this information into the hands of the beekeepers who need it most.
Animal Health Component
78%
Research Effort Categories
Basic
11%
Applied
78%
Developmental
11%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
3113010106050%
2163010108150%
Knowledge Area
311 - Animal Diseases; 216 - Integrated Pest Management Systems;

Subject Of Investigation
3010 - Honey bees;

Field Of Science
1060 - Biology (whole systems); 1081 - Breeding;
Goals / Objectives
Goals and Objectives of "No More Mummies: Novel and integrative treatment options for Ascosphaera apisin honey bees"GoalsOur primary goal is to improve the health and productivity of honey bee colonies by reducing colony losses to chalkbrood disease caused by the fungal pathogen Ascosphaera apis. To do this, we will establish a treatment regiment which encompasses both non-chemical and chemical approaches to ultimately reduce chalkbrood infection in honey bee colonies, training future colleagues and communicating our findings with beekeeping stakeholders throughout the process.Objective 1: Identify promising synthetic and natural chemical compounds that reduce or prevent the growth of Ascosphaera apis and determine their impact to honey bees in laboratory trials. No current treatments are available for beekeepers to combat chalkbrood infections in colonies. We have identified some compounds and will explore others through a series of laboratory-based experiments focusing on cultured A. apis (Obj. 1a), in vitro reared bee larvae (Obj. 1b), and adult honey bees (Obj. 1c).Objective 2: Characterize social and individual immune traits that contribute to chalkbrood resistance. Several honey bee stocks have demonstrated abilities to reduce pests and pathogens naturally, although the mechanisms for this are yet unknown. Previous studies have demonstrated that Russian honey bees in particular have varying susceptibility to chalkbrood. Through both field (Obj. 2a) and laboratory (Obj. 2b) experiments, we will quantify the contribution of key colony-level social immune and individual immune mechanisms of resistance among various lines of Russian honey bees.Objective 3: Investigating and communicating the efficacy of integrative pest management practices for chalkbrood disease. Propolis has is a potent pathogen inhibitor, both in the laboratory and in field settings. Here, we will test the impact of propolis-rich boxes (Obj. 3a) and the newly identified fungicidal compounds (Obj. 3b) to infected colonies in the field separately. Then we will test them in concert with colonies of differing susceptibility to evaluate potential additive benefits of multiple control strategies (Obj. 3c). Finally, we will synthesize our findings into best practices for IPM of chalkbrood disease and broadly disseminate this message to beekeepers worldwide (Obj. 3d).Understanding what makes some groups in a single honey bee population more resistant than others is scientifically valuable and has wide applicability to other diseases and pests within social insects. The results from our proposed work will allow us to communicate chalkbrood IPM strategies which are quantifiably effective in preventing and treating chalkbrood and likely other honey bee diseases through shared social immunity mechanisms. By forming a variety of IPM strategies, we are following best management practices for sustainable and responsible disease management within our crop system and ultimately generating a holistic toolkit for our beekeeping stakeholders.Objectives ListObjective 1: Identify promising synthetic and natural chemical compounds that reduce or prevent the growth of Ascosphaera apis in the laboratory and within individual honey beeso Objective 1a: Screen synthetic and natural chemical compounds for reduction and prevention of A. apis growth on mediao Objective 1b: Determine the effectiveness of compounds in controlling chalkbrood infection of in vitro reared larvaeo Objective 1c: Assess the ability of antifungal compounds to impact the main route of spore transmission from nurse bees to larvaeObjective 2: Determine if any U.S. honey bee stocks are able to naturally reduce instances of chalkbrood infection without beekeeper interventiono Objective 2a: Identify Russian honey bee (RHB) lines that are particularly resistant or susceptible to chalkbrood in the field.o Objective 2b: Determine if resistant or susceptible colony status is due to differential vulnerability of larvae in the laboratory.Objective 3: Developing an integrative pest management program for chalkbroodo Objective 3a: Evaluate if propolis boxes prevent chalkbrood infections in a field setting.o Objective 3b: Assess if promising fungicides can treat chalkbrood infections in a field setting.o Objective 3c: Determine if there is an additive effect of increased propolis and fungicidal treatment on chalkbrood infections for colonies of varying susceptibilityo Objective 3d: Construct technology transfer materials of chalkbrood IPM to stakeholders.
Project Methods
MethodsEffortsObjective 1Different synthetic fungicides and propolis extracts will be evaluated on media according to standard methodology to determine which inhibit Ascosphaera apis growth. Promising fungicidal compounds will then be evaluated after use on honey bee larvae reared in the laboratory (determine LD50) and then further to determine if larvae infected with A. apis and then treated with compounds have a higher chance of survival. Finally, caged newly emerged bees (typically nurses at this age) who routinely vector chalkbrood throughout the colony during outbreaks will be inoculated with A. apis inside of cages in incubators and then treated with the promising fungicidal compounds in order to both determine adult LD50s and potential utility killing A. apis spores while inside of the honey bee proboscis and gut.Objective 2Using historical data in conjunction with recent identifications, we will assess different breeding groups of Russian honey bees (RHB) which have already demonstrated resistance to chalkbrood (the disease caused by A. apis) in previous work completed at the location where we will complete the work. We will measure social immunity traits routinely associated with resistance to other diseases. Resistant and susceptible colonies in the field will used for laboratory assessments of resistance and susceptibility conducted on grafted larvae reared in the laboratory.Objective 3In the field, we will inoculate colonies with A. apis and then utilize all promising treatment options including propolis boxes, promising fungicides, etc. and then conduct final assessments of efficacy. Findings will be communicated to stakeholders and those who primarily work with stakeholders.EvaluationObjective 1We expect to find several additional fungicides in different chemical classes that are able to significantly restrict the growth of chalkbrood. We will significantly increase our screening efforts for chemicals from each class of fungicides and propolis from different geographic origins and plant sources. The results will be written for publication in an international peer-reviewed journal (Objective 1a). We want to continue evaluating the compounds that have the lowest honey bee mortality and the greatest survival when co-exposed along with A. apis spores, but we need to identify those before we can continue evaluations (Objective 1b). We will discover if our fungicides show promising potential to control A. apis inboth honey bee larvae and adult workers (Objectives 1b and 1c), deepening our knowledge of this process and further informing Objective 3b.Objective 2We anticipate a variable response in hygienic behavior and mummy production between different Russian honey bee (RHB) breeding lines (Objective 2a). We suspect that hygienic behavior will negatively correlate with mummy production, as it did historically in the U.S. This result would indicate that RHB and/or the Southeastern U.S. strain of A. apis are very different than the those in Australia, as hygienic behavior is not correlated in any way with mummy production in Australia (where we currently have the most recent data about chalkbrood-honey bee disease ecology).We expect to find that breeding groups that are highly susceptible or highly resistant to A. apis correlate with having larvae which are highly susceptible or highly resistant to A. apis (Objective 2b), this would support the evidence found previously which identified inherited single nucleotide polymorphisms with susceptibility and further explain the variation in findings between RHB susceptibility and resistance to chalkbrood.Objective 3We fully expect that non-chemical based IPM strategies work well to prevent chalkbrood and that the synthetic and non-synthetic treatment options will work in the field as they have already shone great promise in laboratory settings. The Premier Bee Products propolis boxes are a simple and low-energy way for beekeepers to utilize propolis in a field relevant setting, but they are a new product and have not been tested until now. Propolis has worked well to inhibit A. apis growth in the laboratory and field previously, so we do expect the propolis boxes to work well as a preventative management strategy for chalkbrood (Objective 3a). The propolis spray and fungicides (Objective 1) have both inhibited A. apis growth to varying degrees in laboratory settings, so we do expect these results to also inhibit A. apis growth in a field setting (Objective 3b). In total, the toolkit of individual IPM strategies that we are investigating should have an additive negative effect on chalkbrood infections--or mummy production--in colonies (Objective 3c). The information which results from these objectives needs to be synthesized into a coherent IPM strategy toolkit which can be disseminated to the beekeeping industry (Objective 3d), where we expect it will be well-received.

Progress 09/01/24 to 08/31/25

Outputs
Target Audience:The target audience for project information dissemination included both scientific and stakeholder groups since funding was received on Sept 1, 2024-present. Stakeholder groups comprised ofthe Apiary Inspectors of America, the Russian Bee Breeders Association, and the American Beekeeping Federation. Scientific groups included those who the project was announced to and positions were advertised through, such as the American Association of Professional Apiculturists, the Pollinators of the Northeast, Entomological Society of America (national and Southeastern Branches). Stakeholder group dissemination was highly prioritized in order to confirm buy-in and support. To date, stakeholder partner operations have been identified (with emphasis on the Russian Bee Breeders Association) and wesuccessfullycoordinatedin order to work towards the goals of objective 2, which included establishing Russian honey bee colonies at the USDA-ARS location in Baton Rouge, LA. Scientific group information dissemination was initially to announce the project and to recruit promising graduate student and postdoctoral fellow candidates, which was successful. Later updates have been to share Objective 1 and 2 findings to date, which has also been successful at the Entomological Society of America meeting. Changes/Problems:There has been one major problem and change to report: -The USDA-ARS lab was significantly and unexpected understaffed (~50% personnel at facility) and unable to hire additional summer students as proposed. This necessitated a decrease in experimental colony subjects for Obj. 2afrom the proposed N/treatment group. This challenge was overcome by working with less colonies than anticipated, but starting the field work (Obj. 2a) portion of colony screening in 2025 rather than in 2026 as proposed. We anticipate screening additional colonies in 2026, which will allow us to achieve the N originally proposed. What opportunities for training and professional development has the project provided?The graduate student and postdoctoral candidate have both been trained in a workshop-type event in media preparation, chalkbrood inoculation (colony and larval levels), spore quantification, and additional cultural methods. The graduate student began her studies at U-FL in the spring semester (2025). The postdoctoral fellow began in Feb 2025 and has learned field techniques for honey bee disease ecology, as have an undergraduate student and technician(s). This learning was hands-on and individually tailored through one-on-one instruction. How have the results been disseminated to communities of interest?Results thus far have been disseminated to stakeholder and scientific venues in the form of presentations during outreach, extension, and conferences. Presentations include: Hseih, E. 2025. Variable susceptibility to chalkbrood infection between Russian honey bee lines and life stages.Entomological Society of America's Annual Meeting, Portland, Oregon, 37 participants. 12 Nov. [Cancelled due to govt shutdown.] Jack, C. 2025. The search for new active ingredients against honey bee pests and pathogens. Oregon State Beekeepers Association Annual Meeting, Bend, OR, 97 participants. 26 October. Jack, C. 2025. The search for new active ingredients against honey bee pests and pathogens. South Florida Bee College, Seminole, FL, 21 participants. 23 August. Jack, C. 2025. The search for new active ingredients against honey bee pests and pathogens. North Carolina Beekeepers Association Annual Meeting, Flatrock, NC, 360 participants. 12 July. Jack, C. 2025. The search for new active ingredients against honey bee pests and pathogens. Pinellas County Beekeepers Association, Seminole, FL, 64 participants. 22 May. Jack, C. 2025. The search for new active ingredients against honey bee pests and pathogens. Nevada State Beekeepers Association Annual Meeting, Yerington, NV, 125 participants. 22 Feb. Masnjak, A. 2025.Screening antifungal compounds for inhibitory action againstAscosphaera apis, the causative agent of chalkbrood. Entomological Society of America's Annual Meeting, Portland, Oregon, 37 participants. 12 Nov. Simone-Finstrom, M. 2025. Propolis in beekeeping: two decades of research supporting resilient bees. International Propolis Group annual conference. Feb.[virtual participation.] Walsh, E. 2025. Different stock responses to disease. Midwestern Honey Bee Expo, Waukesha, Wisconsin, ~275 participants. 25 Jan. What do you plan to do during the next reporting period to accomplish the goals?Substantial progress in addressing objectives 1 and 2 is completed as according or preceeding our proposed timeline. Obj 1: Various antifungal agents will continue to be screened and then assessed for honey bee larval mortality, as proposed. Obj 2: Russian queens for Obj 2 are established and initial field work (infecting diseases with A. apis) and mesuring colony-level responses has been completed. Findings have been communicated to stakeholder and scientific audiences through presentations thus far. Anticipated accomplishements for the next reporting period include: Additional screening and assessment of antifungal compounds. Continued colony-level assessments of field responses to A. apis infection, paired with in vitro rearing and mortality assessments detailed in 2b. The first peer-reviewed manuscript has an anticipated submission date of 12/2025. Additional stakeholder and scientific reporting in the form of presentations, stakeholder articles, and podcasts, as detailed in proposed timeline.

Impacts
What was accomplished under these goals? We seek to identify novel chalkbrood IPM strategies and then communicate them effectively with stakeholders. Our stakeholders comprise of beekeepers who both breed bees and those who are impacted negatively by chalkbrood within their apiaries. In the year sincethe project has been funded, we have made progress addressing these goals by: 1) completing all funding movements, which include releasing subawards to both ORISE and UFL, which allowed us to 2) identify and hire promising graduate student and postdoctoral fellow candidates (graduate student at U-FL and postdoctoral fellow at the USDA-ARS Baton Rouge). We have made progress on Objectives 1 and 2 according to our proposed timeline, where promising chemical control agents are being examined and Russian honey bees have been procured, established, and initially evaluated. Stakeholder agreements are in place to get adequately diverse queens to screen for the traits which confer resistance to susceptibility to chalkbrood as needed in the future. We have begun objective 2a ahead of schedule this past summer (2025).

Publications