A RAATs protocol will significantly reduce management costs by using less insecticide (chlorpyrifos) and running down fewer soybeans during insecticide application. It would be expected to use this strategy in conjunction with other management tools as part of an overall IPM strategy. Natural enemies are preserved to help manage remaining insect pests or subsequent soybean aphid re-infestations.
Reduced agent and area treatments (RAATs) refers to a treatment method where areas of a field are left unsprayed because the chemical being used vaporizes and will therefore provide control beyond its target site. An example illustration of the field plot area of this experiment is shown below.
We propose to take advantage of the vaporization effect of chlorpyrifos containing insecticides to develop a reduced agent and area treatment strategy (RAATs) for soybean aphid management. The objectives of this study were to 1) determine the effective width of unsprayed strips for soybean aphid management, 2) determine if chlorpyrifos-containing products have same effect as chlorpyrifos alone, 3) determine the effect of treated, untreated strips on natural enemies, 4) determine if other soybean pests can likewise be managed and 5) develop a RAATs protocol for farmers to follow, and present in a "RAATs for Soybean Aphid Management" NebGuide.
Weather conditions during 2014 limited success and validation of RAATs protocols, however, 2012 and 2013 data suggest - 1) RAATs protocol using 8-row non-sprayed strips appears effective to treat soybean aphid in most Nebraska weather conditions, and possibly 16-row non-treated strips when temperatures are near or above 90 degrees F; 2) chlorpyrifos alone at full rate should be used in RAATs protocols; 3) RAATs protocols preserves non-targets and beneficial insects (e.g. predators); 4) RAATs protocols do not appear to be as effective against other soybean pests observed (e.g. stink bugs). Charts illustrating the effects of the RAATs treatment on multiple insect species, both beneficial and pest, are shown below.