title: Acaricidal properties of extracts from the aerial parts of Hypericum polyanthemum on the cattle tick Boophilus microplus.
abstract: Laboratory tests were carried out on larvae and adults of the cattle tick Boophilus microplus to determine the toxicity of n-hexane and crude methanolic extracts of Hypericum polyanthemum (Guttiferae) using the larval immersion test (LIT) and adult immersion test (AIT). In the AIT, the effectiveness of treatment against engorged females was assessed by measuring egg production: the n-hexane extract was found to have a small effect on the egg laying at the highest concentration (19.2% of egg-laying inhibition) whilst the crude methanolic extract did not affect the egg production. For the LIT the n-hexane extracts were highly toxic to the larvae at all the concentrations (100% of mortality). The crude methanolic extract was also toxic to the larvae at higher concentrations killing 100, 96.7, 84.7 and 52.7% at the concentrations of 50, 25, 12.5, and 6.25 mg/ml, respectively, 48 h after the immersion of the acarus.
authors.affiliation: Laboratório de Entomologia, Faculdade de Veterinária, UFRGS, Av. Bento Gonçalves 9090, 91540-000 Porto Alegre, RS, Brazil.
authors.forename: Vera Lucia Sardá
authors.initials: VL
authors.lastname: Ribeiro
authors.forename: Eduardo
authors.initials: E
authors.lastname: Toigo
authors.forename: Sérgio A L
authors.initials: SA
authors.lastname: Bordignon
authors.forename: Karla
authors.initials: K
authors.lastname: Gonçalves
authors.forename: Gilsane
authors.initials: G
authors.lastname: von Poser
mesh_terms: D000818:Animals; D005260:Female; D020902:Hypericum / Q000737:chemistry*; D007306:Insecticides / Q000633:toxicity*; D007814:Larva / Q000187:drug effects; D010058:Oviposition / Q000187:drug effects; D010063:Ovum / Q000187:drug effects; D035261:Plant Components, Aerial / Q000737:chemistry; D010936:Plant Extracts / Q000633:toxicity*; D048494:Rhipicephalus / Q000187:drug effects*; D013983:Tick Control / Q000379:methods; D013984:Tick Infestations / Q000188:drug therapy / Q000662:veterinary*; D023382:Toxicity Tests, Acute
chemical_list: D007306:Insecticides; D010936:Plant Extracts