In 1996 a new organophosphate insecticide, ethion, which had not been used in the United States, was introduced into the insecticide-tag market. Proper use vital Proper tag application affects performance - now and in subsequent years. Adherence to the manufacturer's recommendations is essential for success. Applying tags too early in the season, inadequate numbers of tags and improper placement can all have adverse effects. It also is important to remove the tags after the season so sublethal amounts of insecticide aren't released, leading to more resistance.
Proper application is crucial to achieve season-long retention and control.
The ear tag should be placed in the center of the flat part of the ear between the cartilage ridges so approximately one-half of the tag is exposed below the bottom edge of the ear. This exposes sufficient surface area of the tag for good chemical release and rub-off onto the hair coat. These flies are prevalent under pasture conditions because they require undisturbed cattle manure to develop. This offers significant labor savings when compared to gathering cattle every few weeks for pour-on application or spraying. The first consideration should be which flies are an economic problem in a particular operation.