Tuesday, December 11, 2007
D0315

Analyzing the potential for indirect effects of herbicide use in crops andforestry on threatened and endangered insects

Thomas Martin Priester, tpriester@complianceservices.com, Ashlea (Rives) Frank, arives@complianceservices.com, David Howes, dhowes@complianceservices.com, Rick Kemman, rkemman@complianceservices.com, and Stephanie Dressel, sdressel@complianceservices.com. Compliance Services International, 7501 Bridgeport Way W, Lakewood, WA

Most herbicidal products have little, if any, acute toxicity or developmental and reproductive effects on adult insects. In fact, one of the most common uses of herbicides is to control invasive and noxious plants which may actually benefit sensitive insect species. However, the use of herbicidal products may have indirect effects on insect habitat, diet, and/or oviposition sites, especially on plant-dependent or plant-obligate species. The purpose of this study is to analyze the effects (direct, indirect, and beneficial) of herbicide use on threatened and endangered species. This analysis starts by determining where threatened and endangered insects may be found in association with herbicide use sites (crops and forestry). Determinations can be made as to whether the associated insects are likely to be exposed to herbicides, and if herbicides are likely to be directly toxic to these species. Barring direct toxicity, we can determine if the use of herbicides will have indirect effects on nectar sources, larval food sources, oviposition sites, and/or effects on habitat. Also, we can determine potential beneficial effects due to herbicide’s effect on competitive invasive species that may be reducing or eliminating food sources, oviposition sites and/or habitat for host-specific or obligate insects. For those insect species that are adversely impacted by the use of herbicides, mitigation measures or label warnings can be proposed to prevent or reduce these adverse impacts.


Species 1: Lepidoptera Lycaenidae Lycaeides melissa samuelis (Karner blue butterfly)
Species 2: Lepidoptera Nymphalidae Speyeria zerene hippolyta (Oregon silverspot butterfly)
Species 3: Coleoptera Silphidae Nicrophorus americanus (American burying beetle)