spraying for pests

Full-Text WHO Manual
(50 pp, PDF)

1. Objective
2. Safety
3. Protective Clothing
4. Preparations: The Household
5. Preparations: Equipment
6. Mixing, Handling and Spray Techniques
7. Procedures after Spraying
8. Disposal of Remains of Insecticides and Empty Packaging
9. Maintenance of Equipment
10. Troubleshooting
11. Preparation of Insecticide Spray

Manual for Indoor Residual Spraying:
Application of Residual Sprays for Vector Control

(WHO Communicable Disease Control, Prevention and Eradication,
Pesticide Evaluation Scheme; 2002)

The objective of this illustrated manual (aimed at pest-control workers) is to ensure the safe and correct application of a residual insecticide to indoor surfaces on which malaria vectors may rest. However, it also applicable for any other vector-borne diseases where indoor residual spraying would be an appropriate means of vector control (for example, Chagas disease).

The WHO specifications for public health pesticides are part of the International Code of Conduct on the Distribution and Use of pesticides, and are used for quality control and international trade.

The WHO Pesticide Evaluation Scheme (WHOPES) develops specifications for public health pesticides once they have been fully tested for their safety and efficacy in both the laboratory and the field. WHOPES promotes the safe, judicious and proper use of pesticides, including their safe and proper application. Such application relies mainly on the quality and working conditions of the equipment, as well as the skills and knowledge of the operators using the equipment. WHOPES has developed and published specifications for pesticide application equipment for vector control, to provide the minimum standards and requirements for safe and proper performance.

Indoor residual spraying is extensively used, especially for malaria and Chagas vector control. However, both vector-control programs frequently lack well-trained field staff to apply the insecticides and maintain the application equipment. With good skills and quality application equipment, hazards to human health and the environment—as well as financial losses—can be avoided.

This manual is intended to serve as a 'model' for developing relevant training manuals and procedures at country level, to ensure safe and effective use of insecticides in vector control programmes.

In the original document, working tank-pressure of 70 psi was recommended to overcome one of the major operational problems of spraying in the field, i.e. the unreliability of pressure gauges, the untimely repumping of the tanks, and the formation of large spray droplets that would easily fall on the ground rather than on the intended wall surface. Nevertheless, it has become clear that with a higher initial tank-pressure and consequent changes in output at the nozzle, the speed at which the nozzle is moved by the operator would need to be modified to achieve the recommended dosage. This is not easy to achieve, so the recommendations are now updated to help users obtain a more uniform deposition of insecticide. It is strongly recommended that users fit a "control-flow valves (CFV)" to the nozzle to ensure more uniform output of spray. The valve will open provided the tank pressure exceeds that of the valve setting. Where a CFV is not fitted, the user can revert to a working tank-pressure of 55 psi (3.8 bar).

The revised document also contains easy-to follow steps in preparation of insecticide sprays.