Vector and Pest Control in Refugee Situations (United Nations High Commissioner for Refugees (UNHCR) / Alto Comisionado de Naciones Unidas para los Refugiados (ACNUR), 1997, 124 p.) |

In order to prepare a suspension or a solution from a given formulation of a pesticide in wettable powder or emulsifiable concentrate form, the following formula must be applied:

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where

X = quantity of formulation necessary

A = desired concentration

B = desired quantity of solution

C = concentration of a.i. in the formulation

D = 1 if X and B are expressed in kg or litres; D=8.33 if X and B are expressed in pounds or US gallons and D=10 if X and B are expressed in pounds or imperial (UK) gallons.

**Example:**

To obtain 100 litres of a 2.5% solution from an insecticide formulation containing 50% a.i.:

_{}

Therefore 5 kg or 5 litres of insecticide formulation have to be mixed with 100 litres of water to obtain the solution at the concentration required for filling the pumps.

**N.B.** When using powders for suspensions, the powder
should be put into a receptacle with a little water, and mixed to obtain a
paste. This paste should then be thinned by adding small quantities of water
until the desired volume is attained and the resulting mixture poured through a
filter into the
tank.