Release of piperonyl butoxide and permethrin from synergized ear tags on cattle and effects on horn fly mortality.

摘要: A study was conducted to determine the release rates of piperonyl butoxide (PBO) and permethrin from synergized insecticidal cattle ear tags their effects on mortality horn fly, Hematobia irritans (L.) (Diptera: Muscidae). PBO released at a higher rate than in both winter summer trials. The cumulative end 18 wk trial 50.4 30.3%, respectively. 66.7 44.7%, There significant correlation between daily high ambient temperature (°C) permethrin. Compared with susceptible fly strain, permethrin-resistant strain demonstrated 7.9- 12.8-fold resistance levels LC50 LC90, When exposed filter paper wipes taken shoulders treated PBO-synergized trial, resistant reduced compared strain. 2- 3-h exposure exhibited pattern declining mortalities as result decreased permethrin, well decline ratio PBO:permethrin after 8 wk. similar observed 30-min time that coincided over course trial.