How long will the insecticide last?

The insecticides applied to cattle will be effective for between 5 and 50 days (Vale et al., 1999; Torr et al., 2007). The period varies according to the time of year and the formulation used. The various formulations sold by manufacturers will give an indication of the effective life of the insecticide. In general however, you should not expect the formulation to be effective for more than a month.

Knockdown of tsetse exposed to cattle treated with deltamethrin 0-35 days after treatment.  Cattle were treated all over or the insecticide was restricted to the legs and belly.

Re-drawn from Torr et al., 2007.

References

Torr, S.J., Maudlin, I., Vale, G.A. (2007). Less is more: restricted application of insecticide to cattle to improve the cost and efficacy of tsetse control. Medical and Veterinary Entomology 21(1):53-64. PubMed PMID: WOS:000245546100006.

Vale, G.A., Mutika, G., Lovemore, D.F. (1999). Insecticide-treated cattle for controlling tsetse flies (Diptera : Glossinidae): some questions answered, many posed. Bulletin of Entomological Research 89(6):569-78. PubMed PMID: ISI:000086387600010.