Honey Bee Responses to Blueberry Fungicides and Varroa Miticides While Used in NJ Blueberry Pollination Services

Project Overview

Project Type: Graduate Student
Funds awarded in 2020: $15,000.00
Projected End Date: 08/31/2023
Grant Recipient: Rutgers, The State University of New Jersey
Region: Northeast
State: New Jersey
Graduate Student:
Faculty Advisor:
Dean Polk
Rutgers University


  • Fruits: berries (blueberries)
  • Animals: bees
  • Animal Products: honey


  • Crop Production: pollination, pollinator health
  • Education and Training: extension
  • Pest Management: integrated pest management

    Proposal abstract:

    Beekeepers are experiencing over $1 million in annual losses when pollinating NJ blueberries. Fungicide use over the last decade has increased during bloom which correlates with colony declines. Therefore, investigations on the effects of fungicides are needed.

    Initial work has shown that bees may prefer fungicide laced food sources, while other research has shown bee attractiveness to some fungicides. As part of my dissertation, I found 36 pesticides returned to the hive in pollen, including numerous fungicides. New papers point to the negative impact of fungicides on different bee species, including honey bees. My initial tests showed that some high fungicide rates caused larval mortality. Therefore, we need to determine the influence of blueberry fungicide use on foraging behavior as well as impacts on brood development.

    My objectives include: 1) determining the influence of commonly used blueberry fungicides on honey bee foraging behavior, 2) determining if this behavior influences residues being introduced to the colony, and 3) determining the impacts of in-hive residues on brood development.

    Research components include: Field studies that record honey bee forager visitations in number and consumption rate as influenced by plain syrup vs syrup with various fungicides; pollen and nectar analyses for pesticide residues in hives, and in vitro feeding tests with fungicide amended diet to examine resulting effects on brood and maturation.

    Outreach will include extension newsletters, web-based blogs, and grower winter and spring update meetings. I will work with extension faculty to update the pollinator protection chapter in the NJ Blueberry Production Guide.

    Project objectives from proposal:

    This project extends the work being done on an existing SARE grant, now coming to a conclusion in its 3rd and final season, but having opened additional questions relative to bee behavior and fungicide toxicity. The proposed work is designed to address those questions not addressed in the original SARE project.


    Objective 1. Determine the influence of commonly used blueberry fungicides on honey bee foraging behavior.


    Objective 2. Determine fungicide levels in honey bee hives, and when they are most likely to enter the hive in relation to fungicide spray programs.


    Objective 3. Determine if there is any impact on honey bee brood development and resulting colony health by fungicide levels found in the hive as influenced by objectives 1 and 2.

    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.