Vector and Pest Control in Refugee Situations (United Nations High Commission for Refugee, 1997, 124 p.) |

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When calculating the optimum concentration of active ingredient (a.i.) in the insecticide solution to be used in a spraying treatment, the following factors should be considered:

· quantity of a.i. per m^{2}to be applied;

· throughput speed of the pump (nozzle type and tank pressure);

· speed and method of spraying (see section 14.3.)

**Example:**

In order to determine the insecticide concentration for pirimiphos-methyl 50 CE treatment to be applied using a sprayer, the following points have to be considered:

· surfaces must be treated with 1 g of insecticide a.i. per m^{2};

· spraying speed must be regulated to spread 40 ml solution per m^{2};

· the formulation contains 50% of a.i.;

· so for 40 ml to contain 1 g of a.i., a litre of solution will have to contain 25 g, giving a 2.5% a.i. concentration.

**Example:**

In order to determine the insecticide concentration for deltamethrin 2.5 WP treatment to be applied using a sprayer, the following points have to be considered:

· the surfaces must be treated with 0.025 g of insecticide a.i. per m^{2};

· spraying speed must be regulated to spread 40 ml solution per m^{2};

· the insecticide comes in a 2.5% concentrate formulation;

· so in order that 40 ml contain 0.025 g of a.i., a litre of solution will have to contain 0.625 g, giving a 0.0625% a.i. concentration.