UVM Extension tracks transition from neonicotinoid seed treatments; early results mixed

Heather Darby told committee members that UVM Extension began studying neonicotinoid (neonic) seed treatments before Vermont’s recent law that restricts their use and that the program’s work now emphasizes managing pest risk and documenting where farmers may see crop losses without treated seed.

Darby said there was mixed evidence nationally about the degree to which neonics caused pollinator declines; high‑profile honeybee losses circa 2012–2015 raised concern and prompted further study. Extension and Cornell researchers have examined how seed coatings and planting equipment release dust from planters and whether changes in coatings or the use of different fluency agents reduce dust emissions.

Darby said one year of her group’s data shows that seed coating retention depends on the seed company and that some fluency agents (graphite is commonly used) abrade coatings and increase dust. She said certain alternative fluency agents appear to suppress dust better and that an alternative class of insecticide, diamides, can be effective but is more expensive than neonics and is less broad‑spectrum.

Because Vermont and New York passed similar restrictions, Darby said one farmer concern is whether seed manufacturers can economically produce and inventory non‑treated seed options. She said Quebec uses non‑treated seed for some crops, and diamide‑treated seed is already available from some suppliers. Darby said the Extension work will continue to monitor pest pressure, crop loss risk and the effect of repeated use on soil residues of neonic compounds.

Darby framed the work as transitional: measuring risk and alternatives so farmers can adopt new practices without undue crop loss.