Exposure of Culicoides variipennis (Diptera: Ceratopogonidae) to Hair Clippings to Evaluate Insecticide-impregnated Ear Tags in Cattle1

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Abstract
Adult Culicoides variipennis (Coquillett) exposed to hair samples from cattle treated with one fenvalerate ear tag per animal resulted in mortalities of 87–100% (x¯ = 93%) within 7 days post treatment. Mortalities of 80-100% (x¯ = 95%) were obtained at 6 days from hair samples from untreated cattle placed in the same pen with treated cattle. Insecticidal activity lasted throughout the 70-day test period, with decreased efficacy following rainfall and after the 49th test day. Significantly higher mortalities were recorded from hair samples from the neck near the ears and from the underside of the body.