By Michael Gray
On March 20, 2015, an article published in Environmental Science and Technology confirmed the extensive use of neonicotinoids as insecticidal seed treatments in a wide variety of field crops across the United States. The authors of the article Margaret R. Douglas and John F. Tooker are scientists with the Department of Entomology at The Pennsylvania State University.
Provided below are some direct quotes from their journal article concerning neonicotinoid seed treatments (NSTs):
- “Neonicotinoid use increased rapidly between 2003 and 2011, as seed-applied products were introduced in field crops, marking an unprecedented shift toward large-scale, preemptive insecticide use: 34-44% of soybeans and 79-100% of maize hectares were treated in 2011. This finding contradicts recent analyses, which concluded that insecticides are used today on fewer maize hectares that a decade or two ago.”
- “Importantly, the introduction of NSTs closely followed introduction of Bt hybrids targeting corn rootworms (Diabrotica spp.), a pest complex that has historically driven insecticide use in U.S. maize.”
- “Importantly, however, NSTs are now used on almost triple the area historically treated with non-seed insecticides; therefore, NSTs (together with Bt hybrids) have more than displaced non-seed treatment insecticide use on an area basis.”
- “This finding supports the apparent shift toward an “insurance” paradigm of pest management in maize, in which transgenic crops and NSTs are deployed even when target pest densities are expected to be low. This notion is also supported by a recent survey, in which 39% of maize growers using NSTs were not targeting any particular pest.”
- “Several analyses on the influence of Bt crops on pesticide-use patterns do not seem to have considered seed treatments, and so may have overstated reductions in insecticide use (especially “area treated”) associated with this technology.”
The widespread insurance-based approach to the use of NSTs is likely to persist in corn and escalate in soybean production due to (as the authors of the current journal article point out) — “current incentives and disincentives for farmers and seed suppliers.” As a result, concerns will linger regarding secondary-insect resistance development and potential negative environmental consequences.