Auto‐dissemination of commercially available fungal pathogens in a laboratory assay for management of the brown dog tick Rhipicephalus sanguineus

Abstract

Rhipicephalus sanguineus is a canine tick that infests dogs throughout the world and is frequently found in homes and dog kennels. Management of this tick species is complicated by the presence of resistance to commonly utilized acaricides. Fungal formulations could provide a valuable alternative tool for management and are especially relevant indoors where detrimental environmental effects on fungal spores are of less concern. Two commercially available fungal formulations, one containing Metarhizium anisopliae and the other containing Beauveria bassiana, were compared for time to death and sporulation in nymphal ticks exposed for 60 min in treated filter paper packets. Beauveria bassiana exposure killed ticks faster than M. anisopliae exposure and B. bassiana was more likely to sporulate on tick cadavers than M. anisopliae.To determine whether infected ticks could disseminate fungus to their conspecifics, ticks were marked and treated with fungus before being placed with untreated ticks. Fungus was successfully transmitted from treated to untreated ticks. Mortality of ticks exposed to B. bassiana-exposed conspecifics occurred sooner than for those exposed to M. anisopliae-exposed conspecifics, indicating faster dissemination in the former. Therefore, although both formulations resulted in decreased longevity of ticks compared with the controls, the B. bassiana formulation holds the most promise for direct or indirect application with respect to brown dog tick management.

A Review of Commercial Metarhizium- and Beauveria-Based Biopesticides for the Biological Control of Ticks in the USA

“…When immersed in up to 10 8 conidia/mL, 100% mortality occurred after three weeks in the European species I. ricinus and D. reticulatus [ 53 ]. Over 90% mortality within four weeks has been observed in aggregated R. sanguineus sensu lato [ 54 ]. This species is commonly found indoors in dog kennels and homes and is known to be permethrin resistant and tolerant to fipronil, which are commonly used for its control [ 69 ].…”

“…For example, mortality of D. albipictus larvae was significantly less when treated with Bb -GHA (30–41%) in comparison to Mb -F52 (82–99%) when the two strains were applied at the same rates [ 52 ]. In contrast, Bb -GHA killed R. sanguineus sensu lato nymphs faster and caused greater sporulation than Mb -F52 [ 54 ]. This difference might be attributed to B. bassiana ’s propensity for profuse sporulation under more diverse conditions, where 91.5% of ticks that were infected with Bb -GHA sporulated compared with 77.3% of those infected with Mb -F52.…”

Garrapata café del perro

“…La Organización Mundial de la Salud hace una clasificación de plaguicidas por peligrosidad donde incluyen a los acaricidas para el control de garrapatas (WHO, 2006;. (Sullivan et al, 2022;Weeks et al, 2020) Además, no se recomienda llevar a las mascotas a zonas silvestres y conservadas. Por lo tanto, es muy importante evitar el contacto de la mascota con la flora y fauna silvestre.…”

Entomopathogenic Fungi and Bacteria in a Veterinary Perspective

“…Furthermore, a synergistic effect of both EPFs on Rhipicephalus appendiculatus and Amblyomma variegatum [152,153] was referred, too. In a recent comparative study on the efficacy of the autodispersion of commercially available strains of M. anisopliae and B. bassiana against nymphal stages of R. sanguineus, the latter fungal species was faster in killing ticks and more efficient in sporulating on cadavers, allowing a mold dissemination [154].…”