CONTROL OF INSECTS IN THE URBAN ENVIRONMENT WITH FILM-FORMING AQUEOUS SPRAY FORMULATIONS THAT MINIMISE THE USE OF HYDROCARBON SOLVENTS

Abstract:
Insecticidal space sprays are widely and effectively used for control of insects in the urban environment. They are especially useful for flying insect control, be it for disease vector or nuisance pest, but space sprays can also be very effective for rapid control of crawling pests such as cockroaches. Consumer acceptance of insecticide treatments is an increasingly important aspect to be considered for successful insect control. Traditional techniques such as thermal fogging and misting employ large quantities of hydrocarbon solvents to both formulate and dilute the concentrates. Ultra-low volume (ULV) techniques, which consume up to one hundredth the quantity of solvents used for thermal fogging, are more efficient. However, the move towards using water as diluent is not straightforward because of its greater volatility compared to diesel; this leads to droplets which rapidly shrink after generation and quickly become too small to impact efficiently on insects. ULV formulations are described in which water is used not only as the diluent but also to replace most of the hydrocarbon solvent normally present in emulsifiable concentrate formulations. As a result of the surface film-fonning action of these formulations, evaporation of water from the droplets is demonstrably reduced. Spray characteristics and biological performances against a variety of insect types and under different climatic conditions are described