How long will a target last?
The effective life of a target depends on the effective lives of:
- the insecticide
- the attractants
- the cloth and poles
Thus the effective life of a target depends on the materials you use; a target made from, say, very durable canvas and steel would last longer than one made from thin cotton and wooden poles.
We can treat targets with formulations of insecticide which will be effective for many months. For instance, treating a target with suspension concentrate formulations of 0.4% deltamethrin, or 0.4% beta-cyfluthrin or 0.8% alphacypermethrin produces high (>70%) mortalities for nine months. And 0.8% formulations of beta-cyfluthrin and deltamethrin are effective for more than a year (Mangwiro et al., 1999).
We can also bait targets with attractant dispensers that are effective for many months; a low-density polythene dispenser filled with 20 g of a 12:1:6 blend of 4-methylphenol:3-n-propylphenol:octenol will last for more than a year (Torr et al., 1997).
Similarly suitable cloth and poles - made from steel or wood - can also last a year.
So in general we can deploy a target that will be effective for a year. Tsetse Plan provides specific advice on what materials, insecticides and attractants you should use to achieve this.
In contrast, tiny targets for riverine species do not get re-treated with insecticide and instead get replaced at the end of their effective life. In Guinea, Côte d’Ivoire and Chad targets are replaced annually while in Uganda and DRC targets are replaced after 6 months.
Targets will be lost to theft, fire, storms, vandalism and damage caused by livestock and wild animals. So while targets can last for up to a year, a proportion will not. In the case of targets for savanna species, it is important that you aim to re-visit targets at about three-month intervals to repair or replace these.
Mangwiro, T.N.C., Torr, S.J., Cox, J.R. & Holloway M.T.P. (1999). The efficacy of various pyrethroid insecticides for use on odour-baited targets to control tsetse. Medical and Veterinary Entomology, 13, 315-323.
Torr, S.J., Hall, D.R., Phelps, R.J. & Vale, G.A. (1997). Methods for dispensing odour attractants for tsetse flies (Diptera: Glossinidae). Bulletin of Entomological Research, 87, 299-311.