Spray Drift Management
Author: Bretthauer, Scott
Source: Outlooks on Pest Management, Volume 22, Number 6, December 2011 , pp. 262-267(6)
Publisher: Research Information
Abstract:The misapplication of pesticides can occur in a variety of ways. One of the most common is spray (or particle) drift, which occurs when portions of the pesticide spray leave the intended target area and travel through the air off-target to a site not intended for application. Spray drift is affected by multiple factors and in order to manage drift effectively, it is important to understand these factors and how they interact. The factors that affect drift can be loosely grouped into two categories: application related and weather related. Those factors related to the application can be adjusted by the applicator based on the equipment selection, setup, and use and by the products used in the spray solution. Weather factors are beyond the control of the applicator, but knowledge of how they impact drift is still critical so that application factors can be adjusted as needed to deal with the current weather conditions. The objective of this article to provide a review of the factors related to drift so that applicators can manage spray drift better during an application. There are multiple factors that affect drift, and there are many interactions between these factors. However, droplet size is the most important factor and can be modified by the applicator, which means it should be the key focus when managing applications for drift. All of the other factors' impact on drift is in part determined by the droplet size. Fast wind speeds, inversions, high temperatures, and tall boom heights can be partially mitigated by using larger droplet sizes. Conversely, a small droplet size will increase the risk of drift even when spraying under optimum weather conditions. Other technologies, including electronic control systems and drift reduction additives, can also be used to create and maintain the desired droplet spectrum. However, no one technology can completely eliminate the risk of drift, and failure to understand how the factors relate can result in a drift incident even when the applicator utilizes one or more drift reducing technologies. Care should also be taken not to sacrifice efficacy for the sake of drift reduction. For certain pesticides that require the usage of smaller droplets in order to provide adequate coverage, this may mean spraying under a narrower set of weather conditions and the use of a larger buffer zone. The best spray drift management strategy involves selecting the largest droplet size that still provides good pest control, selecting and operating nozzles and adjuvants that provide that droplet size, and spraying under weather conditions that are conducive to keeping the spray on target.
Document Type: Research Article
Publication date: December 1, 2011