title: Does the effect of a Metarhizium anisopliae isolate on Rhipicephalus microplus depend on the tick population evaluated?
abstract: The filamentous fungus Metarhizium anisopliae is an arthropod pathogen used in the biological control of pests in agriculture and livestock. The effect of the fungus M. anisopliae on ticks has been shown in experiments in vitro. The aim of the present study was to compare the susceptibility of different field isolates of Rhipicephalus microplus to M. anisopliae. A total of 67 field isolates were evaluated. Rhipicephalus microplus larvae were immersed in an M. anisopliae suspension (108conidia/mL) for 5min. The median lethal times (LT50) ranged from 2.6 to 24.9days. Mortality observed at the 15th day after treatment ranged from 26.3 to 100% in the tested samples. The effect of M. anisopliae on tick isolates was not associated with their susceptibility to any acaricide tested, animal stocking rate, cattle breed, rotational grazing, cultivated pasture, production system, presence of wet areas or biome. The integration of livestock and agriculture practices in the farm and the frequency of acaricide treatment seem to be associated with tick susceptibility to M. anisopliae. These results demonstrated that field populations of R. microplus show a high variation in their susceptibility to M. anisopliae.
authors.affiliation: Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Programa de pós-graduação em Biologia Celular e Molecular, Porto Alegre, RS, Brazil; Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF), Fundação Estadual de Pesquisa Agropecuária (FEPAGRO), Eldorado do Sul, RS, Brazil. Electronic address: anelise.webster@gmail.com.
authors.forename: Anelise
authors.initials: A
authors.lastname: Webster
authors.affiliation: Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF), Fundação Estadual de Pesquisa Agropecuária (FEPAGRO), Eldorado do Sul, RS, Brazil.
authors.forename: Endrigo
authors.initials: E
authors.lastname: Pradel
authors.affiliation: Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF), Fundação Estadual de Pesquisa Agropecuária (FEPAGRO), Eldorado do Sul, RS, Brazil.
authors.forename: Ugo Araújo
authors.initials: UA
authors.lastname: Souza
authors.affiliation: Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF), Fundação Estadual de Pesquisa Agropecuária (FEPAGRO), Eldorado do Sul, RS, Brazil.
authors.forename: João Ricardo
authors.initials: JR
authors.lastname: Martins
authors.affiliation: Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF), Fundação Estadual de Pesquisa Agropecuária (FEPAGRO), Eldorado do Sul, RS, Brazil.
authors.forename: José
authors.initials: J
authors.lastname: Reck
authors.affiliation: Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Programa de pós-graduação em Biologia Celular e Molecular, Porto Alegre, RS, Brazil.
authors.forename: Augusto
authors.initials: A
authors.lastname: Schrank
authors.affiliation: Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF), Fundação Estadual de Pesquisa Agropecuária (FEPAGRO), Eldorado do Sul, RS, Brazil.
authors.forename: Guilherme
authors.initials: G
authors.lastname: Klafke
mesh_terms: D056810:Acaricides / Q000494:pharmacology; D000818:Animals; D054884:Host-Pathogen Interactions; D007305:Insecticide Resistance; D007814:Larva; D052981:Metarhizium / Q000502:physiology*; D010572:Pest Control, Biological; D048494:Rhipicephalus / Q000145:classification / Q000187:drug effects / Q000382:microbiology*
chemical_list: D056810:Acaricides
keywords: Biological control; Fungus; Ixodidae; acaripathogenic fungi