|Vector Control - Methods for Use by Individuals and Communities (WHO, 1997, 425 p.)|
|Chapter 9 - House-spraying with residual insecticides|
|Manually operated sprayers|
There are many different types of hand-operated sprayer. Most models are used for the control of agricultural pests. With some adaptations such sprayers may also be suitable for use in public health and for household pest control. The World Health Organization has produced detailed specifications of spraying equipment suitable for residual wall-spraying in order to ensure uniform and safe application of insecticides (3).
Types of hand-operated sprayer
Usually considered the standard equipment for residual spraying. However, many models are available and only a few comply with WHO specifications, which are discussed further in the text.
Widely used in agriculture, this is carried on the back. A frame or shield prevents contact between the tank and the back. It is a continuous type of sprayer with a fairly constant discharge rate. The person maintains pressure in the tank by pumping air with a lever with one hand and directs the spray lance with the other. If the sprayer is fitted with a spray control valve, continuous pumping may not be necessary. The knapsack sprayer can be used for spraying breeding sites with larvicides but should not be used for residual wall-spraying.
These are used in some vector control programmes because they are less costly than compression sprayers. The pump, mounted on a footrest or stirrup, is inserted in the spray liquid in a bucket. A hose attached to the pump leads to the spray lance. Two persons are needed, one to pump and one to direct the spray. The pressure varies with the speed of pumping, and so it is difficult to make uniform spray applications. Because of their inaccuracy and because of the risk of spilling insecticide from the open bucket inside houses, stirrup pumps are not recommended. They should not be used with hazardous pesticides.
Fig. 9.3 A stirrup pump.