Insecticide ear tags

 Dave Boxler

By Dave Boxler 
Nebraska Extension Educator

Insecticide-impregnated ear tags were first introduced in the late 1970s, and have been used to the reduce face fly (top photo) and horn fly (bottom photo) populations. Active ingredients in insecticide ear tags kill flies by direct contact. Small amounts of an insecticide is released from the ear tag into the oils present on animal’s hair. The face, neck, topline and flanks receive the most product through natural grooming behavior. Interaction between cattle enhances the transfer of product between animals.

During the past 40 years, the active ingredients within ear tags have been organophosphate and synthetic pyrethroid classes. In the early 2000s, a macrocyclic lactone class was developed and provided an alternative to organophosphate and synthetic pyrethroid insecticides to help manage horn fly resistance.

Fly tags impregnated with either a macrocyclic lactone, organophosphate or a pyrethroid can provide long-term protection throughout the fly season. Strategic timing of fly tag application is key to successful fly control. Research suggests that fly burden does not result in economic loss until horn fly numbers reach 200 or more flies per animal. Therefore, it is recommended that tags should not be applied until this threshold is met, usually late May or early June in Nebraska. Most currently available fly tags offer protection for 12 to 15 weeks, but are most effective during the first 45 to 60 days following application. Fly tags applied too early in the grazing season may be largely expended and not offer enough protection during peak fly season. In Nebraska, it is strongly recommended to apply 2 tags per adult or yearling animal to obtain maximum fly reduction. If attempting to control face flies to reduce pinkeye in calves, then calves will need to be tagged in both ears. Annual rotation among pyrethroid, organophosphate, and macrocyclic lactone tags and the removal of tags at the end of the season is recommended to help mitigate problems with emerging fly resistance.

Following is a list of available insecticide ear tags listed by mode of action:

  • Organophosphate: Corathon®, Dominator®, MAX40™, Optimizer®, Patriot™, Warrior™
  • Synthetic Pyrethroid: CyLence Ultra®, Gardstar®, PYthon®, PYthon MagnuM™, Saber™ Extra
  • Macrocyclic lactone: XP820®
  • Combination of two modes of action: Double Barrel®VP, TRI-ZAP™

To wrap up, here are a few notes and updates regarding fly control in cattle this year. A new insecticide ear tag for 2020 is MAX40™ which contains a 40% concentration of diazinon. Insecticide ear tag strips which have been marketed by Y-TEX, will not be available for this fly season.

As always, please read and follow label directions before using any insecticide product.

cow with eartags

cow with flies