Edible baits for systemic flea control, plague mitigation, and wildlife conservation: Evaluation of four active ingredients with three rodent species in western North America

International Journal of Parasitology: Parasites and Wildlife
By: , and 

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Abstract

The flea-borne agent of plague, Yersinia pestis, is lethal to endangered black-footed ferrets (Mustela nigripes, BFFs) and the prairie dogs (Cynomys spp., PDs) on which BFFs depend for habitat and prey. We developed bait pellets containing insecticides for flea control with PDs. Individual baits contained 0.46, 0.91, 1.21, or 1.52 mg fipronil, 5.40 mg afoxolaner, 50.62 mg fluralaner, or 85.20 mg spinosad. From 2023 to 2025, we tested the baits with black-tailed PDs (C. ludovicianus, BTPDs), Gunnison's PDs (C. gunnisoni, GPDs), and Richardson's ground squirrels (Urocitellus richardsonii, RGSs). We sampled hosts 2810 times and detected 8825 fleas across 2 U.S. States, 1 Canadian Province, 6 sites, 9 PD colonies, and 41 sampling plots. Over ∼12 mo across 5 replicates in South Dakota, USA, bait pellets with 0.91 or 1.52 mg fipronil, applied at a rate of 125 baits/ha, were more effective in reducing the abundance of fleas on BTPDs than 0.46 mg fipronil or the 3 other active ingredients; on 2 South Dakota replicates with data from 24 mo posttreatment, the effects of fipronil pellets on flea abundance had waned after ∼24 mo. Similarly, over ∼12 mo on 2 replicates in Arizona, USA, pellets with 1.52 mg fipronil were more effective in reducing the abundance of fleas on GPDs than pellets with 0.46 mg fipronil; on 1 replicate with available data from ∼2 yr posttreatment, the effects of fipronil pellets had waned after ∼24 mo. Over ∼8-11 mo across 2 replicates in Saskatchewan, Canada, baits with 1.21 mg fipronil/pellet were more effective in suppressing the abundance of fleas on BTPDs and RGSs when applied at 250 pellets/ha than 62 pellets/ha; flea control had waned after ∼20-23 mo. When applied annually at 125-250/ha, baits with 0.84-1.52 mg fipronil (FipBits) provided an effective, efficient, and affordable tool for flea control on PD colonies.

Suggested Citation

Eads, D., Matchett, M.R., McCaffery, M., Hemmah, A., Jarding, A.R., Cordova, J., Heimann, H., Liccioli, S., Gardiner, L.E., Cormack, J., Hicks, H., Fly, J., Childers, E., Livieri, T., Hladik, M.L., and Biggins, D.E., 2026, Edible baits for systemic flea control, plague mitigation, and wildlife conservation: Evaluation of four active ingredients with three rodent species in western North America: International Journal of Parasitology: Parasites and Wildlife, v. 29, 101216, 12 p., https://doi.org/10.1016/j.ijppaw.2026.101216.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Edible baits for systemic flea control, plague mitigation, and wildlife conservation: Evaluation of four active ingredients with three rodent species in western North America
Series title International Journal of Parasitology: Parasites and Wildlife
DOI 10.1016/j.ijppaw.2026.101216
Volume 29
Year Published 2026
Language English
Publisher Elsevier
Contributing office(s) California Water Science Center
Description 101216, 12 p.
Country Canada, United States
State Arizona, Saskatchewan, South Dakota
Other Geospatial North America
Additional publication details