Toxicity of synergized permethrin residues in cattle dung to two temperate dung beetle species after application of common livestock pour-on treatment

Agriculture, Ecosystems, and Environment
By: , and 

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Abstract

Essential to pasture health, dung beetles (Coleoptera: Scarabaeidae) provide key ecosystem services across natural and managed rangeland habitats. Insecticide residues in livestock dung can negatively impact dung beetle populations, and synergized pyrethroid products are commonly used to combat resistant pest fly populations. Here, permethrin residues were measured by GC-MS/MS in fresh cattle feces on Days −2 (pretreatment), 4, 8, 16, and 30 after the label rate application of a formulated pour-on treatment (a.i. 5% permethrin, 5% piperonyl butoxide [PBO]). Mean (± SE) measured permethrin concentrations were the highest on Day 4 at 1400 ± 360 ng of permethrin/g of dung (dry weight) with a maximum concentration of 2200 ng/g. Approximately, 99% of applied permethrin was excreted by Day 16, with no detection by Day 30. Field-collected dung was used in a 48-hour toxicity test and with three treatment groups (control [Day −2], low risk [Day 16], and high risk [Day 4]). Two temperate dung beetle species were tested: Onthophagus pennsylvanicus Harold and Canthon chalcites Haldeman. Mean (± SE) mortality of O. pennsylvanicus was 28 ± 5% and 58 ± 13% for low and high risk treatments, respectively. Mean (± SE) mortality of C. chalcites was lower than O. pennsylvanicus with 10 ± 4% and 40 ± 10% for low and high risk treatments, respectively. PBO was detected on Days 4 and 8, and the permethrin:PBO ratio was 10:1 on Day 4, i.e., high risk treatment. Data presented highlight episodic risks of pour-on products and support threshold-based, integrated pest management approaches.

Suggested Citation

Cavallaro, M.C., Hladik, M.L., Soares, R., Anderson, M., and Hoback, W.W., 2026, Toxicity of synergized permethrin residues in cattle dung to two temperate dung beetle species after application of common livestock pour-on treatment: Agriculture, Ecosystems, and Environment, v. 408, 110511, 8 p., https://doi.org/10.1016/j.agee.2026.110511.

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Publication type Article
Publication Subtype Journal Article
Title Toxicity of synergized permethrin residues in cattle dung to two temperate dung beetle species after application of common livestock pour-on treatment
Series title Agriculture, Ecosystems, and Environment
DOI 10.1016/j.agee.2026.110511
Volume 408
Publication Date May 12, 2026
Year Published 2026
Language English
Publisher Elsevier
Contributing office(s) California Water Science Center
Description 110511, 8 p.
Country United States
State Oklahoma
County Lincoln County
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