Use of pyrethroid impregnated tags in the control of sheep headfly disease

Plastic tags containing 8.5 per cent w/w cypermethrin or 10 per cent w/w permethrin reduced the severity of damage caused to sheep by the headfly Hydrotaea irritans. A similar pattern of protection extended from the tagged ewes to their untagged lambs. Tags containing 8.5 per cent w/w fenvalerate failed to reduce the level of headfly damage in gimmers.