Spray drift research

United States, a major research programme was initiated in 1990 by a consortium of about 39 chemical companies, the Spray Drift Task Force (SDTF). The SDTF which was formed to support spray-drift registration requirements for the US Environment Protection Agency (EPA), conducted an extensive trial programme consisting of some 300 experimental applications. 

Droplet Technologies Inc. 937-1 West Whitehall Road, State College, PA 16801, USA. Johnson, D., Spray Drift Task Force (1997) A Summary of aerial Application Studies Stewart Agricultural Research Services, PO Box 509, Macon, Missouri 63552, USA. 

Spray Drift Taskforce A Summary of Spray Application Studies, Stewart Agricultural Research Services, Missouri (1997). 

Multinational companies have shown interest in the development of application technologies, but commitment has not been sustained where intellectual property rights (IPR) in large markets could not be established. Disappointingly few farmers worldwide are aware of alternatives to conventional hydraulic sprayers, which inefficiently use large volumes of water, but remain by far the most important method of pesticide application. Worse still, recent emphasis in application research has focused on the reduction of spray drift (especially in Europe and North America). The most common solution to be implemented to date has been to increase droplet size spectra (without necessarily improving spray quality) thus spray application has probably become generally more inefficient. 

A considerable amount of research effort has been expended for the management of spray drift in Europe and North America. However, not only has exodrift been reduced at the expense of endodrift (as discussed above), but conventional drift control may also impose substantial burdens on the development of environmentally benign microbial agents. Since effective delivery... 

Spray Drift Task Force, David Johnson at Stewart Agricultural Research Services, Inc., Macon Missouri 1997. 

Vertical surfaces collect spray primarily by impaction. Plants and other entities with a vertical component will collect some material by impaction, and typically also by deposition, as discussed in the previous section. While horizontal collectors will tend to collect all or most material that falls out on to them, vertical collectors will have collection efficiencies that are more closely related to their physical characteristics, especially collector diameter. The SDTF used a-cellulose cards oriented perpendicular to the ground and strings made of cotton or Teflon in its field studies to assess spray volumes at locations above the ground. Many other researchers have used strings for assessing airborne spray volumes in drift studies. ... 

Granules are mostly used for application to soil and water. They are useful in variety of insect control situations. Examples include application to the seed bed for seed protection, broadcasting and tilling into the soil for soil insect control, application to growing crops for either foliar or soil insect control, and application to ponds for mosquito control. They are easy to apply and are not as likely to drift as dusts or spray. They have less tendency to adhere to foliage and can thus be applied to soil surface through a canopy of leaves. Researchers often find that when different formulations of a toxicant are compared, the granules perform better. 

But there was the possibility of an even larger attack. Diseases might be sprayed into the air from a ship or aircraft, and allowed to drift across the country. To discover whether such attacks, feasible in theory, were practical propositions, the British, Canadians and Americans collaborated in a succession of experiments. After preliminary meteorological research to discover how clouds of bacteria might behave at altitude, they began a series of mock attacks. 

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