Synergistic action of fatty acids, sulphides and stilbene against acaricide-resistant Rhipicephalus microplus ticks.
Six compounds in a methanolic extract of Petiveria alliacea stem (cis-stilbene; benzyl disulphide; benzyl trisulphide; and methyl esters of hexadecanoic acid, octadecadienoic acid and octadecenoic acid) are known to exercise acaricide activity against cattle tick Rhipicephalus microplus larvae and adults. The synergistic effect of 57 combinations of these six compounds on acaricide activity against R. microplus was evaluated. Larvae immersion tests produced the lethal concentrations needed to kill 50% (LC50) and 99% (LC99) of the population. Adult immersion tests produced rates (%) for mortality, oviposition inhibition and eclosion inhibition. Individually, none of the compounds (1% concentration) exhibited acaricide activity (mortality ≤2.3%). When combined, however, nine mixtures exhibited a synergistic increase in activity, with high mortality rates (≥92%) in larvae. Values for LC50ranged from 0.07 to 0.51% and those for LC99from 0.66 to 5.16%. Thirty six compound mixtures had no significant activity (mortality ≤30%) against larvae. Two mixtures exhibited synergism against adults, with high rates (≥92%) of oviposition inhibition. The mixtures based on the benzyl disulphide+benzyl trisulphide pairing produced a synergistic effect against acaricide-resistant R. microplus larva and adults, and are therefore the most promising combination for controlling this ubiquitous ectoparasite.
Laboratorio de Parasitología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Carretera Mérida-Xmatkuil Km. 15.5, 97100 Mérida, Yucatán, Mexico.
G N
GN
Arceo-Medina
Laboratorio de Parasitología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Carretera Mérida-Xmatkuil Km. 15.5, 97100 Mérida, Yucatán, Mexico. Electronic address: alberto.rosadoaguilar@gmail.com.
J A
JA
Rosado-Aguilar
Laboratorio de Parasitología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Carretera Mérida-Xmatkuil Km. 15.5, 97100 Mérida, Yucatán, Mexico.
R I
RI
Rodríguez-Vivas
Centro de Investigación Científica de Yucatán, Calle 43 No. 130, Col. Chuburná de Hidalgo, 97200 Mérida, Yucatán, Mexico.
R
R
Borges-Argaez
D056810:Acaricides / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy / Q000469:parasitology; D004351:Drug Resistance; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D005227:Fatty Acids / Q000494:pharmacology*; D005260:Female; D007814:Larva / Q000187:drug effects; D010058:Oviposition / Q000187:drug effects; D029602:Phytolaccaceae / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology; D018547:Plant Stems / Q000737:chemistry; D048494:Rhipicephalus / Q000187:drug effects*; D013267:Stilbenes / Q000494:pharmacology*; D013440:Sulfides / Q000494:pharmacology*; D013984:Tick Infestations / Q000469:parasitology / Q000517:prevention & control / Q000662:veterinary
D056810:Acaricides; D005227:Fatty Acids; D010936:Plant Extracts; D013267:Stilbenes; D013440:Sulfides
Benzyl disulphide; Benzyl trisulphide; Rhipicephalus microplus; Synergism