WOOSTER, Ohio - As growers plant corn, there is potential for insecticide drift from planters that could impact pollinators, says an entomologist with Ohio State University's College of Food, Agricultural, and Environmental Sciences.
Insecticide seed treatments used on corn seed produce an insecticidal dust when they are planted, said Reed Johnson, an entomologist with the Ohio Agricultural Research and Development Center (OARDC).
OARDC is the college's statewide research arm.
"Depending on conditions, this insecticidal dust can settle on the flowering trees and weeds frequented by bees," Johnson said. "The dust can be packed up with the pollen and then be transported back to the colony where it can have the potential to poison young and developing bees.
"Whether the exposure is enough to cause a problem in every situation is still a question."
One way to lessen the potential impact is for growers to follow manufacturers' guidelines for seed treatment applications.
Growers can also, as part of the planter tune-up process, avoid cleaning out the dust from the planter on top of or upwind of flowers that are attractive to bees, such as dandelions, mustards and purple deadnettle growing in corn fields and on field margins, Johnson said.
"There is still a lot that we don't know," he said. "We've got research planned this year to figure out what the conditions are in which bees are exposed to or harmed by corn seed insecticides, with a goal that hopefully we can give people better recommendations on what can be done to lessen the potential."