Seed Treatment with Neonicotinoids

Jed Cappellazzi
CPS Agronomy

Bee Covered in Pollen (by: Forest Wander)
There has been a tremendous amount of "buzz" about Neonicotinoids, or "Neo-nics" as they are called.  These neurotoxins share a chemical resemblance to nicotine and are much less toxic to mammals than traditional insecticides.  Neo-nics include those implicated in Oregon's bee kills over the summer of 2013, imidacloprid and dinotefuran, which may face future use restrictions.  There was even a recent protest in Corvallis.  As part of the Agricultural family in the Willamette Valley, CPS is dedicated to providing growers with safe and effective methods of controlling pests, supporting beneficial insect populations and the latest information on important topics.

As such, we wanted to bring recent research to your attention.  The Tangent CPS blog has previously posted about Neo-nics and bees before, but as we embark on a new growing season we thought this would peak the interest of some.  You can also view the new EPA "Bee Label" which highlights safe insecticide use.  

Conceptually, rates of Neo-nics are higher when applied as foliar sprays or soil drenches than when treating seed.  Seed treatments also result in less drift, environmental contamination and non-target action provided dust release is minimized during planting.  Some research has suggested, however, that as Neo-nics are incorporated into the germinating seed and go systemic throughout the plant they may concentrate in guttation fluid or other tissues.  Little is known about Neo-nic accumulation in pollen which, if  substantial, could lead to colony collapse through queen exposure to concentrated, contaminated pollen brought back to the hive by workers.

Very recently, research by the Entomology Society of America (Dr. Gus Lorenz) suggests barely detectable levels of Neo-nics, if any, were found in pollen.  This would mean that expression of harmful chemicals does not occur in reproductive plant parts.  This research is still pending publication and peer-review, but the results could indicate the safety of seed treatments that provide similar effectiveness and reduced levels in the environment.  Here is some further commentary on the research written in Forbes Magazine.

I hope this information was helpful as we continue to elucidate better ways to use chemical tools against pests while supporting beneficials.  Bees are, perhaps, the most beneficial of all.