Chemical Methods
Chemical control methods are many and varied and have been increasingly used since the second half of the nineteenth century. Since the 1940s and 1950s, chemical control methods have tended to dominate urban pest control strategies.
The manufacturers of chemical methods have responded and continue to develop and improve products which meet the general public's criteria for health, safety and efficiency.
Manufacturers invest many millions of dollars in the development, improvement and marketing of new products and the last thing they want to see is these products being used inappropriately by ill trained, poorly equipped technicians. Most, if not all manufacturers recognise and actively support an integrated approach to urban pest management. They appreciate that their products must be part of an overall IPM strategy to be most effective.
Chemical methods have developed over the last decade or so from the "one can and spray it anywhere" mentality, to a very selective approach.
The choice of chemical methods involves a thorough assessment of the situation and then the selection of the most appropriate;
a) active ingredient or combination of active ingredients
b) formulation
c) application equipment and technology
and d) application strategy.
The choice of the active ingredient or combination of active ingredients to be used, will depend on the range of pests being treated, the surfaces to be treated, the client's requirements, and many other factors.
The formulation chosen will also be a very significant determinant of the effectiveness and longevity of the treatment. For example wettable powder (WP) formulations will often provide greater efficiency on absorbent surfaces than say emulsifiable concentrate (EC) formulation. In some instances there may be a need to use several different formulations of the same active ingredient to treat an area effectively.
Application equipment selection will to a large degree be determined by the choice of formulations to be applied. However, nozzle selection for example will vary depending on the situation being treated. For example, the use of a flat fan spray nozzle will not be effective in the treatment of cracks and crevices, nor will a pin-stream nozzle effectively treat broad surfaces. Nozzle selection is a vital variable to achieve maximum treatment efficiency.
Application strategy involves the most appropriate placement of the product to maximise pest population reduction. The primary goal with respect to pesticide placement is to target the treatment at pest harbourages or sources of infestation.
A target oriented application strategy will always be more effective in limiting the pest population, will use less pesticide and in the long run it will be more profitable. Warning....targeted application will require a trained, thinking and active technician. The alternative broad spraying of old, is no doubt initially faster, easier and requires less thinking, however it uses more insecticide, may be less effective long-term, is less profitable and less professional.