Acaricidal activity of Metarhizium anisopliae isolated from paddocks in the Mexican tropics against two populations of the cattle tick Rhipicephalus microplus |
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| Authors: | A FERNÁNDEZ ‐SALAS M A ALONSO‐DÍAZ R A ALONSO‐MORALES R LEZAMA‐GUTIÉRREZ J C RODRÍGUEZ‐RODRÍGUEZ J A CERVANTES‐CHÁVEZ |
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| Institution: | 1. Centro de Ense?anza, Investigación y Extensión en Ganadería Tropical, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México (UNAM), Martínez de la Torre, Veracruz, México;2. Departamento de Genética y Bioestadística, Facultad de Medicina Veterinaria y Zootecnia, UNAM, México City, México;3. Facultad de Ciencias Biológicas y Agropecuarias, Universidad de Colima, Tecomán, Colima, México;4. Colección de Hongos Entomopatógenos del Centro Nacional de Referencia de Control Biológico, Tecomán, Colima, México;5. Unidad de Microbiología Básica y Aplicada, Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Santiago de Querétaro, Querétaro, México |
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| Abstract: | The acaricidal effects of 55 strains of Metarhizium anisopliae (Metschnikoff) Sorokin, 1883 (Hypocreales: Clavicipitaceae) isolated from paddocks of cattle farms were evaluated in two Rhipicephalus microplus (Canestrini 1887) (Ixodida: Ixodidae) populations, of which one was multi‐resistant and one was susceptible to chemical acaricides. Percentage mortality and reproductive efficiency indices in R. microplus were evaluated by adult immersion tests at a dose of 1 × 108 conidia/mL for each fungal strain. Some strains were selected to calculate lethal concentrations to kill 50% (LC50) and 99% (LC99) of engorged ticks. Strains MaV22, MaV26 and MaV55 induced 100% mortality in R. microplus on day 14. Strains MaV05, MaV09 and MaV22 caused mortality of >90% from day 12 onward in both tick populations. The most effective acaricidal fungal strain, MaV55, inhibited egg laying by 54.86 and 55.86% in acaricide‐resistant and ‐susceptible R. microplus populations, respectively. None of the fungal strains had statistically significant effects on larval hatching. In conclusion, nine strains of M. anisopliae demonstrated high acaricidal effects against R. microplus and reduced its egg laying. No differences in acaricidal effects were observed between the two populations of ticks tested. |
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| Keywords: | Biological control cattle farms entomopathogenic fungi ticks |
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