title: Assessment of fungal isolates for development of a myco-acaricide for cattle tick control.
abstract: Entomopathogenic fungal isolates of Arachnid origin were assessed for their ability to produce mortality and inhibit egg hatching in Boophilus microplus with the aim of selecting an isolate for development into a myco-acaricide for control of cattle ticks. The ability of the most promising isolate to target developmental stages of more than one tick species and the optimum concentration of fungal inoculum to be used for future studies were determined. Metarhizium anisopliae was the most pathogenic of the three fungal species tested on B. microplus, producing shorter average survival times (ASTs) for engorged adults (AST = 5.2 +/- 0.1 days) and larvae (AST = 9.3 +/- 0.4 days), and a longer average hatching times (AHT; AHT = 19.8 +/- 0.5 days) in comparison to Simplicillium lamellicola and Paecilomyces farinosus. In comparative studies on two tick species with similar life cycles, M. anisopliae produced a shorter AST in engorged adult B. microplus (AST = 8.8 +/- 0.3 days) than Rhipicephalus sanguineus (AST = 10.3 +/- 0.3 days). M. anisopliae was pathogenic to larvae of B. microplus (AST = 7.7 +/- 0.4 days), however, had no effect on larvae of R. sanguineus (AST = 14.6 +/- 0.3 days) as the AST of this treatment was similar to its untreated control (AST = 14.1 +/- 0.4 days). M. anisopliae lengthened the AHTs in both B. microplus (AHT = 16.4 +/- 0.3 days) and R. sanguineus (AHT = 16.7 +/- 0.3 days) in comparison to the controls. The ASTs of engorged adult B. microplus treated with M. anisopliae shortened as the concentration was increased from 1 x 10(7) to 5 x 10(8) conidia/ mL. A further increase in concentration, 1 x 10(9) conidia/mL (AST = 10.2 +/- 0.4 days) did not shorten or lengthen the AST in comparison to 5 x 10(8) conidia/mL (AST = 9.4 +/- 0.3 days).
authors.affiliation: CAB International, Caribbean and Latin America Regional Centre, Curepe, Trinidad and Tobago. P.Polar@cabi.org
authors.forename: Perry
authors.initials: P
authors.lastname: Polar
authors.forename: Moses T K
authors.initials: MT
authors.lastname: Kairo
authors.forename: Dorothy
authors.initials: D
authors.lastname: Peterkin
authors.forename: Dave
authors.initials: D
authors.lastname: Moore
authors.forename: Rupert
authors.initials: R
authors.lastname: Pegram
authors.forename: Sally-Ann
authors.initials: SA
authors.lastname: John
mesh_terms: D000818:Animals; D001096:Arachnid Vectors / Q000254:growth & development*; D002417:Cattle; D002418:Cattle Diseases / Q000469:parasitology / Q000517:prevention & control*; D005260:Female; D026863:Ixodidae / Q000254:growth & development*; D007814:Larva; D008018:Life Cycle Stages; D003904:Mitosporic Fungi / Q000472:pathogenicity / Q000502:physiology*; D010270:Parasite Egg Count / Q000662:veterinary; D010572:Pest Control, Biological / Q000379:methods*; D013983:Tick Control / Q000379:methods; D013984:Tick Infestations / Q000517:prevention & control / Q000662:veterinary*; D013997:Time Factors