Translocation of the neonicotinoid seed treatment clothianidin in maize

PLoS One. 2017 Mar 10;12(3):e0173836. doi: 10.1371/journal.pone.0173836. eCollection 2017.

Abstract

Neonicotinoid seed treatments, typically clothianidin or thiamethoxam, are routinely applied to >80% of maize (corn) seed grown in North America where they are marketed as a targeted pesticide delivery system. Despite this widespread use, the amount of compound translocated into plant tissue from the initial seed treatment to provide protection has not been reported. Our two year field study compared concentrations of clothianidin seed treatments in maize to that of maize without neonicotinoid seed treatments and found neonicotinoids present in root tissues up to 34 days post planting. Plant-bound clothianidin concentrations followed an exponential decay pattern with initially high values followed by a rapid decrease within the first ~20 days post planting. A maximum of 1.34% of the initial seed treatment was successfully recovered from plant tissues in both study years and a maximum of 0.26% was recovered from root tissue. Our findings show neonicotinoid seed treatments may provide protection from some early season secondary maize pests. However, the proportion of the neonicotinoid seed treatment clothianidin translocated into plant tissues throughout the growing season is low overall and this observation may provide a mechanism to explain reports of inconsistent efficacy of this pest management approach and increasing detections of environmental neonicotinoids.

MeSH terms

  • Animals
  • Biological Transport / drug effects
  • Coleoptera
  • Crop Protection / economics
  • Crop Protection / methods*
  • Guanidines / pharmacokinetics*
  • Neonicotinoids
  • Plant Roots / drug effects
  • Seeds / drug effects*
  • Seeds / metabolism
  • Thiazoles / pharmacokinetics*
  • Zea mays / drug effects*
  • Zea mays / growth & development
  • Zea mays / metabolism

Substances

  • Guanidines
  • Neonicotinoids
  • Thiazoles
  • clothianidin

Grants and funding

This research was funded by the Purdue Research Foundation.The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.