Understanding Pest and Disease Transmission Dynamics and Effects of Agrochemicals on Honey Bee Colonies Pollinating Crops in the Western States

Final report for SW15-058

Project Type: Research and Education
Funds awarded in 2015: $248,025.00
Projected End Date: 12/31/2018
Grant Recipient: Oregon State University
Region: Western
State: Oregon
Principal Investigator:
Dr. Ramesh Sagili
Oregon State University
Expand All

Project Information

Abstract:

Honey bee pollination is estimated to be worth more than $17 billion in the U.S. (Calderone 2012). Honey bees are critical for production of several crops in the western states, including California almonds which account for 75% of world production and are valued at $3.6 billion. When other cropping systems are included, West Coast beekeepers provide nearly half of the nation’s commercial pollination services. Recent annual honey bee colony losses (averaging 30%) are alarming to both beekeepers and growers, who are interdependent for their economic viability. Beekeepers have identified several areas of concern in the West Coast pollination circuit. Risks to honey bees include (1) pathogen exposure and transmission between closely packed colonies in holding yards, (2) exposure to agrochemicals (e.g. fungicides and insecticides) applied during bloom, and (3) poor nutrition.

The pollination year begins when the majority of commercially managed honey bee colonies (~1.7 million) are transported to California to meet almond pollination demands each February. The almond cropping system represents an incubator for epidemics as colonies across the nation are transported here for pollination. This could severely affect the entire country’s pollination services. In spite of this potential threat, there is little prospective pathogen monitoring of honey bee and none reaching the scope of our proposed work.

During almond bloom, and in each subsequent pollinated crop, honey bees are exposed to multiple applications of agrochemicals. Many of these pesticides persist in hive materials, resulting in prolonged exposures. These exposures may weaken colonies and make them more likely to succumb to the diseases and pathogens they contracted from closely placed colonies in almonds. Our goal is to characterize synergistic effects between agrochemicals and honey bee diseases, which has been little investigated in field settings. Our results will help to mitigate risk to pollination services for almonds and other crops (blueberry, seed crops) dependent on bee pollination.

Together with beekeepers and growers, we have identified pesticide groups and exposure scenarios of particular concern during the pollination year. These include fungicides sprayed during almond and blueberry pollination, novel antifeedant insecticides applied during pollination of seedcrops, and neonicotinoids used in chemigation systems in watermelons. Our strategy is to monitor transfer of pests and pathogens and exposure to fungicides and insecticides in selected experimental colonies during pollination of these crops. By correlating our results with stakeholder input and survey responses, we will identify practices that minimize bee diseases and pesticide exposures that effect honey bee colony health in these crops. Multiple communication tools will be used to solicit input and encourage cooperation between multiple stakeholder groups in implementing strategies suggested by our results. The stakeholders (beekeepers and growers) will be involved during all phases of this study, including designing experiment to data collection. The information obtained from this study could potentially be used in other bee pollinated crops to promote bee health and pollination services.

Project Objectives:

Objective 1: Analyze patterns in management practices that potentially affect honey bee colony health in almonds, blueberry and carrot seed crop.

Both grower and beekeeper practices that are likely to influence pesticide exposure and disease transmission in bees will be investigated. By evaluating colony health and the concentration of fungicides and insecticides in hive materials, the success of these practices will be assessed.

i) Evaluate management practices that affect honey bee health
ii) Correlate concentrations of pesticides in bee bread and comb wax with application timing and methods
iii) Survey beekeeper and grower behavior, attitudes, and economic data

Objective 2: Isolate risk factors using laboratory and semi-field studies

We will perform controlled experiments to identify practices that are most and least likely to result in colony losses.

i) Identify parameters that decrease transfer of pests and pathogens between selected experimental colonies
ii) Characterize toxicity of selected pesticides and assess their risk to bees at field concentrations

Objective 3: Identify strategies to improve colony health and mutual economic benefit

We will identify the factors which incur the most risk to colonies and work with stakeholders, particularly our advisory panel, to analyze the cost and feasibility of modifying these practices.

i) Identify significant risk factors
ii) Work with stakeholders to weigh cost/benefit/feasibility of potential interventions to growers and beekeepers

Objective 4: Synthesize and disseminate new information and measure impacts

Using multiple methods, we will communicate best practices to stakeholders.

i) Conduct stakeholder advisory panel meetings to review scientific results and direct communication of best practices
ii) Create outreach and informational materials
iii) Design evaluation tools to assess economic, social, and environmental impacts

Cooperators

Click linked name(s) to expand
  • Carolyn Breece
  • George Hansen
  • Pat Heitkam
  • Louisa Hooven
  • Mark Johnson
  • Bruce Martens
  • Bert Van Ryn

Research

Hypothesis:

Objective 1: Analyze patterns in management practices that potentially affect honey bee colony health in almonds, blueberry and carrot seed crop.

Both grower and beekeeper practices that are likely to influence pesticide exposure and disease transmission in bees were investigated. By evaluating colony health and the concentration of fungicides and insecticides in hive materials, the success of these practices was assessed.

i) Evaluate management practices that affect honey bee health
ii) Correlate concentrations of pesticides in bee bread and comb wax with application timing and methods
iii) Survey beekeeper and grower behavior, attitudes, and economic data

Objective 2: Isolate risk factors using laboratory and semi-field studies

i) Identify parameters that decrease transfer of pests and pathogens between selected experimental colonies 
ii) Characterize toxicity of selected pesticides and assess their risk to bees at field concentrations

Objective 3: Identify strategies to improve colony health and mutual economic benefit

i) Identify significant risk factors
ii) Work with stakeholders to weigh cost/benefit/feasibility of potential interventions to growers and beekeepers

Objective 4: Synthesize and disseminate new information and measure impacts

 

Materials and methods:

The experimental honey bee colonies were sampled during 2016 and 2017 in three cropping systems (almonds, blueberries, carrot seed) and in late fall before overwintering. We sampled 144 colonies pertaining to the collaborating beekeepers during almond pollination in California, blueberry pollination in Oregon and also carrot seed crop pollination in Oregon. The final sample for each calendar year was obtained from these colonies during late fall. During each year the same 144 colonies were also sampled two more times during almond pollination after the initial sampling. The final samples for 2016 and 2017 were obtained when the experimental colonies were in respective winter yards in late fall. Bee samples were analyzed for pests/pathogens (Varroa, Nosema) and pollen samples were stored in freezer for pesticide analysis. Further, colony evaluations (number of frames of bees) were performed for all the experimental colonies.

We also sent an extensive survey to both beekeepers and growers to gather information pertaining to management practices.

Research results and discussion:
Research conclusions:

Impacts

WSARE Agrochemical Study 2016 Figures of Results

Accomplishments

We sampled experimental honey bee colonies during 2016 and 2017 in three cropping systems (almonds, blueberries, carrot seed) and in late fall before overwintering. We sampled 144 colonies pertaining to the collaborating beekeepers during almond pollination in California, blueberry pollination in Oregon and also carrot seed crop pollination in Oregon. The final sample for each calendar year was obtained from these colonies during late fall. The same 144 colonies were also sampled two more times during almond pollination after the initial sampling. The final samples for 2016 and 2017 were obtained when the experimental colonies were in respective winter yards in late fall. Bee samples were analyzed for pests/pathogens (Varroa, Nosema) and pollen samples were stored in freezer for pesticide analysis. Further, colony evaluations (number of frames of bees) were performed for all the experimental colonies. We also sent an extensive survey to both beekeepers and growers to gather information pertaining to management practices.

Both Varroa and Nosema analysis data indicates significant variation in intensity levels of Varroa and Nosema at different times of sampling (in different crops). We have not received all the pesticide analysis data yet from the pesticide analysis lab. Once we have the pesticide analysis data available we will be able to run correlations between pathogen/parasite incidence/intensities with respective agro-chemicals found in the experiemntal hives. This information will help us formulate best management practices for both beekeepers and growers.

 

Participation Summary
9 Farmers participating in research

Education

Educational approach:

Findings from this study were disseminated at the 2017 and 2018 American Bee Research Conference and at 6 regional beekeepers association meetings in Oregon (2017 and 2018 Oregon State Beekeepers Associations meeting, Central Oregon Beekeepers Association, Southern Oregon Beekeepers Association, Klamath Falls Beekeepers Association, Lane County Beekeepers Association, Linn-Benton Beekeepers Association, Central Coast Beekeepers Association).

Educational & Outreach Activities

25 Consultations
15 Tours
5 Webinars / talks / presentations
5 Workshop field days

Participation Summary:

600 Farmers
28 Ag professionals participated
Education/outreach description:

We participated in one-on-one meetings (consultations) with beekeepers and growers to discuss our findings and provide recommendations regarding best management practices to improve honey bee health. We also organized workshops and tours for both beekeepers and growers to disseminate information gleaned from our study.

Learning Outcomes

130 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
Key areas taught:
  • Critical times for honey bee pest and pathogen monitoring and treatment
  • How to assess nutritional status of honey bee colonies
Key changes:
  • Pest and disease transmission in honey bee colonies

  • Impact of agro-chemicals on honey bees pollinating crops

Project Outcomes

24 Farmers changed or adopted a practice
600 Farmers intend/plan to change their practice(s)
2 Grants received that built upon this project
5 New working collaborations
Project outcomes:

Knowledge generated from this project is helping both beekeepers and growers understand the risks associated with placement of bees in close quarters in holding yards or in crops for pollination. Further, our findings are also assisting both growers and beekeepers to design appropriate management practices to mitigate pest/disease transmission and agrochemical exposure. We estimate annual savings of approximately $ 10 million (based on our 2016 Qualtrics survey sent to stakeholders) to just Oregon beekeepers alone by following the management recommendations based on our study. Our research efforts have also led to significant changes in behavior among beekeepers and growers that in turn has led to improved honey bee health and sustainable pollination.

Information Products

  • Oregon State University Bee Research Update (Conference/Presentation Material)
  • Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.