Author ORCID Identifier

https://orcid.org/0009-0001-7976-9300

Semester

Summer

Date of Graduation

2024

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Not Listed

Committee Chair

Elizabeth Rowen

Committee Co-Chair

Joseph Lynch

Committee Member

Joseph Lynch

Committee Member

Teiya Kijimoto

Abstract

Ecosystem services provided by dung-associated beetles, such as reducing pasture fouling, parasite suppression, supporting nutrient recycling, and increasing water infiltration, contribute to animal and pasture health. However, parasiticides used to manage cattle parasites, particularly flies and helminths, in West Virginia, can adversely affect these non-target beetles. We assessed the exposure and impact of some parasiticides used in WV including Clarifly® (active ingredient [a.i.] diflubenzuron), Cydectin® (a.i. moxidectin), LongRange® (a.i. eprinomectin), and Safe-guard® (a.i. fenbendazole). In Chapter 1, we review the use of parasiticides in the US and their non-target effects on beneficial dung-associated beetles. In Chapter 2, using high-performance liquid chromatography (HPLC) with fluorescent detection (FLD), we quantified the residual concentrations of these chemicals in cattle feces over 150 d. We found moxidectin and fenbendazole excreted within the first 3 days after treatment (DAT), while eprinomectin and diflubenzuron persisted for 8-12 weeks. The average excretions of these products were 2.4 – 40 mg/kg for fenbendazole, 1.43 – 8.9 mg/kg for diflubenzuron, 0.7 – 7.1 mg/kg for eprinomectin, and 0.01 mg/kg for moxidectin. In Chapter 3, to estimate what concentrations of these active ingredients are toxic to beneficial beetles, we used field toxicity assays with cattle dung dosed with diflubenzuron (a.i. in Clarifly®; 0.09, 1, 9mg/kg), eprinomectin (a.i. in LongRange®; 0.05, 0.2, 0.4mg/kg), or fenbendazole (a.i. in Safe-guard®; 0.3, 3, 10mg/kg) and monitored the first-generation emergence of beetles. We found that Scarabaeidae abundance can be negatively impacted by diflubenzuron at concentrations as low as 1 mg/kg and eprinomectin at concentrations of 0.05 mg/kg while fenbendazole treatments appeared to have no negative effects. Predatory beetles were unaffected by all chemicals. Our results from these two experiments for eprinomectin highlight that, even conservatively, dung from animals treated with LongRange® is toxic to Scarabaeidae for 30 to 90 DAT. Similarly, diflubenzuron is toxic to Scarabaeidae when cattle consistently consume it, although the amount of diflubenzuron in cattle dung when using Clarifly® can be highly variable among years. In contrast, the active ingredient in Safe-guard®, fenbendazole, is not toxic up to 10 mg/kg, and although it may excrete at higher concentrations, this only lasts 1 DAT, posing little to no risk to beneficial species. Producers who value beneficial beetles as a management goal should avoid parasiticides that utilize diflubenzuron (i.e. Clarifly®) or eprinomectin (i.e. LongRange®) as their active ingredient.

Comments

I was told my signed Thesis and Dissertation Signature Form was completed electronically by my committee who all were RIF by the University. Please let me know if I need to update this on my end.

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