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Over the last 60 years pesticides, have found themselves increasingly in the public eye, with glyphosate and neonicotinoids attaining something akin to notoriety in recent years with regular media coverage. A subject receiving considerably less attention however, is the equipment used for pesticide application and the ways in which it can dramatically reduce the risks associated with pesticide use.
The post-war years
Pesticide use became widespread after WW2 as part of the push to boost crop production, particularly in arable crops in temperate climates, where mechanisation and water availability led to the development of standard, vehicle-mounted, boom sprayers, using hydraulic energy nozzles. Boom sprayers had first seen use in the 1920s but it was the 1950s and 1960s which saw their general adoption in the developed countries. Aerial spraying was used to cover larger areas, including plantation crops in developing countries. There was however, very limited use of pesticides in smallholder systems due to their cost and, in the arid tropics, the limited availability of water.
The Green Revolution in the 1960s and 1970s demonstrated the capability of dramatically increasing crop yields in developing countries, thereby potentially helping prevent poverty and indeed starvation. As a result, hand-held sprayers, particularly the Lever Operated Knapsack Sprayer (LOKS), have now become the most widely used sprayers worldwide, with tens, if not hundreds, of millions of smallholder farmers using them today.
In developed countries, the 1960s and 1970s were quite literally, boom years for vehicle mounted sprayers. However, by the early 1980s, the constraints to work rates of high volume (200l/ha or more) application using hydraulic energy nozzles had become apparent. Rapidly increasing farm sizes with a decreasing availability of agricultural labour meant that the 1980s saw significant innovation in application technology for low volume application from boom sprayers. This saw research into Controlled Droplet Application (CDA) using rotary atomisers, initially developed to help smallholder farmers in arid areas efficiently protect their crops, followed by twin fluid and air assisted sprayers, with electrostatically charged sprays also researched as an alternative application method.
The stereotypical image of a sprayer in the current debates about pesticide application (still mainly in the developed countries) remains that of a vehicle mounted boom sprayer. Air assisted sprayers for tree and bush crops and other...