Effects of Imidacloprid Soil Drench Applications on Nesting Blue Orchard Mason Bees (Osmia lignaria)

Project Overview

Project Type: Graduate Student
Funds awarded in 2018: $16,490.00
Projected End Date: 08/31/2020
Grant Recipient: University of Georgia
Region: Southern
State: Georgia
Graduate Student:
Major Professor:
Dr. Kamal Gandhi
University of Georgia


  • Animals: bees


  • Animal Production: animal protection and health
  • Crop Production: pollination, pollinator habitat, pollinator health


    This project seeks to elucidate the multiple pathways by which wild bees may be impacted by neonicotinoid pesticide residues in soils that are used for nesting material. While significant progress has been made with regards to our understanding of the impact of neonicotinoid pesticides on honeybees and dietary exposure to residue in pollen and nectar, little is known about other exposure pathways which may exist for wild bees which use a variety of materials beyond pollen and nectar to complete their life cycles. Use of mud by mason bees (Osmia spp.) is thought to be a potential source of exposure to pesticide residue which has not been examined.  Osmia species are an economically important group of pollinators which are commonly managed for orchard crops such as apple, cherry and blueberry (Bosch and Kemp 2000, Bosch et al. 2000, Bosch and Kemp 2002, Monzón et al. 2004, Sampson et al. 2004, Bosch et al. 2006).  Imidacloprid residues can persist in soils for weeks or months after application, in concentrations ranging from 300 to 1200ppm within the immediate treatment areas (Knoepp et al. 2012, Fletcher et al. 2018).  This project represents the first attempt to look at nesting materials as a potential exposure pathway for mason bees to neonicotinoid pesticides, utilizing the species Osmia lignaria Say. 

    Project objectives:

    Objective 1: To determine how adult female mason bee nest establishment is affected by imidacloprid soil drench treatments when treated mud is used for nesting.

    Objective 2: To determine how offspring which develop within nests with treated soil are affected, in terms of survivorship and sublethal effects such as size, weight, and sex ratio.

    Objective 3: To determine if female mason bees will detect or choose soils with lower residual concentrations of neonicotinoid.

    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.