Results of acaricide testing with the Mexican susceptible strain of Boophilus microplus.

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Results of acaricide testing with the Mexican
susceptible strain of Boophilus microplus.

• R. J. Miller
• USDA ARS

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Introduction

• Single reference strain needed for the Americas
• Puerto Alegre showed resistance
• Discussed several methods to remove the
  resistance from this population
• Finally, it was decided that it would be best to
  study the Mexican susceptible population after
  viewing data presented by Dr. Fragoso in 2004

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Materials and Methods

• Ticks
• The Mexican susceptible population (FAO) was
  tested against two populations collected in
  Texas, USA
• Muñoz
• USA standard susceptible population
• Las Palmas
• Recently collected population and a potential
  replacement for the USA susceptible population

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Materials and Methods

• Acaricides
• 5 acaricides were used in this evaluation
• Coumaphos
• Permethrin
• Amitraz (formulated Taktic 12.5 E.C.)
• Ivermectin
• Doramectin

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Materials and Methods

• Bioassay
• The standard FAO Larval Packet Test was used for
  coumaphos and permethrin
• Nylon fabric was substituted for the bioassays
  with amitraz
• Both LPT techniques (Whatman paper and nylon
  fabric as acaricide substrates) were used for the
  macrocyclic lactone testing

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Results
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Results
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Results
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Results
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Results
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Conclusion

• Mexican population appears to be susceptible to
  all acaricides tested
• This population could serve as a reference
  population for the Americas
• Considerations
• Age of this population in colony
• The risk of transporting pathogens along with the
  reference population (Babesia)