Consider other parasites when treating

Many fly control products also affect other external parasites and some, most notably those containing the macrocyclic lactone compounds, also affect internal parasites. Use of these chemicals for fly control can also select for resistance in the other parasites. It is important to read the label to determine which parasites will be controlled. Resistance is a significant issue in buffalo flies, ticks and cattle worms and when choosing a chemical for fly control consider the possible effects of increasing selection for resistance in non-targeted parasites.