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ARS Home » Plains Area » Kerrville, Texas » Knipling-Bushland U.S. Livestock Insects Research Laboratory » LAPRU » Research » Publications at this Location » Publication #351668
Title: Pyrethroid and organophosphate pesticide resistance in field populations of horn fly in Brazil

Author
item BRITO, LUCIANA - Embrapa
item BARBIERI, FABIO - Embrapa
item ROCHA, RODRIGO - Embrapa
item SANTOS, A - Non ARS Employee
item SILVA, R - Embrapa
item RIBEIRO, M - Embrapa
item Guerrero, Felicito
item FOIL, LANE - Louisiana State University
item OLIVEIRA, MARCIA - Embrapa

Submitted to: Medical and Veterinary Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/30/2017
Publication Date: 8/20/2018
Citation: Brito, L., Barbieri, F., Rocha, R., Santos, A., Silva, R., Ribeiro, M., Guerrero, F., Foil, L., Oliveira, M. 2018. Pyrethroid and organophosphate pesticide resistance in field populations of horn fly in Brazil. Medical and Veterinary Entomology. 33:121-130. https://doi.org/10.1111/mve.12330.
DOI: https://doi.org/10.1111/mve.12330

Interpretive Summary: Pesticides are used worldwide to control arthropod parasites in cattle herds. The indiscriminate and/or inappropriate use of pesticides without veterinary guidance is a reality in several countries of South America. Improper pesticide use increases the chances for contamination of food and the environment with chemical pesticides and their metabolites. Reduction of these contamination events is an increasing challenge for those involved in livestock production. The horn fly, Haematobia irritans (Linnaeus) (Diptera:Muscidae), is one of the most economically important parasites affecting cattle herds around the world. As such, horn fly control efforts are often required to promote the best productive performance of herds. Pesticide resistance bioassays revealed that pyrethroid resistance was widespread and reached high levels in horn fly populations in the Brazilian state of Rondônia. A DNA-based test found that a gene mutation in the horn fly sodium channel, known as kdr, that has been proven to cause pyrethroid resistance was detected in all the horn fly populations that were sampled (n=48). A second sodium channel mutation, known as super kdr, was found in many of these populations also. The super kdr mutation gives rise to high levels of pyrethroid resistance. Organophosphate resistance was not identified in any of the fly populations evaluated.

Technical Abstract: Pesticides are used worldwide to control arthropod parasites in cattle herds. The indiscriminate and/or inappropriate use of pesticides without veterinary guidance is a reality in several countries of South America. Improper pesticide use increases the chances for contamination of food and the environment with chemical pesticides and their metabolites. Reduction of these contamination events is an increasing challenge for those involved in livestock production. The horn fly, Haematobia irritans (Linnaeus) (Diptera:Muscidae), is one of the most economically important parasites affecting cattle herds around the world. As such, horn fly control efforts are often required to promote the best productive performance of herds. Pesticide susceptibility bioassays revealed that pyrethroid resistance was widespread and reached high levels in horn fly populations in the Brazilian state of Rondônia. The kdr sodium channel gene mutation was detected in all horn fly populations studied (n=48), and the super kdr sodium channel gene mutation was found in all homozygous resistant kdr individuals (n=204). Organophosphate resistance was not identified in any of the fly populations evaluated.