Pesticidal Paints: An Integral Approach to Colour your Imagination

Abstract

IntroductionRecent advances in paint technology have guided the development of novel "ready-to-use" paint formulations in which microencapsulated insecticides, or active ingredients (AIs), are embedded in the paint matrix and gradually released on the surface of the dried paint.1 It is argued that the slow-release mechanisms enable uniform AI surface concentrations with prolonged residual effect, as compared to earlier PP products using a simple admixture of AIs in standard paint formulations.2 Depending on the chemical action of the embedded AIs, PPs may display different properties, including spatial repellency, contact irritancy, toxicity, insecticide synergy, or insect growth regulation. Importantly, different AIs can be combined in a single PP to ensure different modes of action in one product.Slow-release (Pesticidal paints) formulations seem to cope with the problem of quick degradation of insecticide on mud surfaces as well as with absorption. They are based on latex or polyvinyl acetate and can be applied to walls by spraying or brushing. Application of the paint by brushing has the advantage of being simpler and cheaper than conventional insecticide application, taking into account the long persistence of the products. However, mud walls are not very suitable for brushing, which erodes the surface; spraying covers the surface with a thin film and is preferred by vector control agencies because it is less time-consuming and more efficient. Recently an insecticidal paint effective against triatomine bugs (T. infestans) has been specially developed for spraying on mud surfaces. It is also suitable for brushon application.3 After drying, it becomes transparent and produces a thin plastic film. This product has to be mixed with water before application.Only insecticides with a high vapour pressure can be used, because the particles have to move to the surface of the paint layer. Malathion, propoxur, pirimiphos methyl and fenitrothion are suitable. Thus 8.3% malathion emulsifiable concentrate or wettable powder added to an emulsifiable suspension consisting mainly of polyvinyl acetate, after drying, leaves a thin film containing around 13% of active ingredient that continuously migrates to the surface. AdvantagesThe insecticidal paints have greater persistence and therefore are more cost-effective than conventional insecticides. One application may last up to two years, whereas standard formulations of insecticides such as the synthetic pyrethroids and Benzene hexachloride (BHC) do not last longer than a year. In a study in Brazil the cost of keeping a house free of triatomine bugs for one year was estimated at US$29 for paint, $73 for BHC, and between $31 and $66 for most common pyrethroids. The paints are appreciated by house owners because they make mud walls more resistant to abrasion. DisadvantagesA larger quantity of formulation is needed per house and precautions have to be taken to prevent blockage of spray nozzles by the polymerizing latex.The insecticidal paints were Ines fly 5A IGR (Insect Growth ...

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“…The results achieved in paint technology in recent years are promoting this field as a new efficient vector control strategy. Recently, formulations commonly termed as insecticidal paints (IPs) have been developed; the active ingredient is added to the paint to provide a "ready-to-use" product in which the insecticide is released in a controlled way once the paint is dried [5][6][7].…”