Campus Units
Entomology, Natural Resource Ecology and Management, Toxicology
Document Type
Article
Publication Version
Published Version
Publication Date
2020
Journal or Book Title
Environmental Toxicology and Chemistry
DOI
10.1002/etc.4672
Abstract
Establishment and maintenance of milkweed plants (Asclepias spp.) in agricultural landscapes of the north central United States are needed to reverse the decline of North America's eastern monarch butterfly (Danaus plexippus) population. Because of a lack of toxicity data, it is unclear how insecticide use may reduce monarch productivity when milkweed habitat is placed near maize and soybean fields. To assess the potential effects of foliar insecticides, acute cuticular and dietary toxicity of 5 representative active ingredients were determined: beta‐cyfluthrin (pyrethroid), chlorantraniliprole (anthranilic diamide), chlorpyrifos (organophosphate), and imidacloprid and thiamethoxam (neonicotinoids). Cuticular median lethal dose values for first instars ranged from 9.2 × 10–3 to 79 μg/g larvae for beta‐cyfluthrin and chlorpyrifos, respectively. Dietary median lethal concentration values for second instars ranged from 8.3 × 10–3 to 8.4 μg/g milkweed leaf for chlorantraniliprole and chlorpyrifos, respectively. To estimate larval mortality rates downwind from treated fields, modeled insecticide exposures to larvae and milkweed leaves were compared to dose–response curves obtained from bioassays with first‐, second‐, third‐, and fifth‐instar larvae. For aerial applications to manage soybean aphids, mortality rates at 60 m downwind were highest for beta‐cyfluthrin and chlorantraniliprole following cuticular and dietary exposure, respectively, and lowest for thiamethoxam. To estimate landscape‐scale risks, field‐scale mortality rates must be considered in the context of spatial and temporal patterns of insecticide use.
Rights
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
Language
en
File Format
application/pdf
Recommended Citation
Krishnan, Niranjana; Zhang, Yang; Bidne, Keith G.; Hellmich, Richard L.; Coats, Joel R.; and Bradbury, Steven P., "Assessing field‐scale risks of foliar insecticide applications to monarch butterfly (Danaus plexippus) larvae" (2020). Entomology Publications. 559.
https://lib.dr.iastate.edu/ent_pubs/559
Included in
Entomology Commons, Natural Resources and Conservation Commons, Population Biology Commons
Comments
This article is published as Krishnan, Niranjana, Yang Zhang, Keith G. Bidne, Richard L. Hellmich, Joel R. Coats, and Steven P. Bradbury. "Assessing field‐scale risks of foliar insecticide applications to monarch butterfly (Danaus plexippus) larvae." Environmental Toxicology and Chemistry (2020). doi: 10.1002/etc.4672.