Pesticide spray drift can harm the environment, the applicator and others near the treatment area. State laws, FIFRA, and Pesticide labels require applicators to take measures to prevent spray drift, but little information is known about which practices applicators actually use to reduce spray drift or how often they use these practices. Time, cost, equipment, and knowledge may limit which practices are routinely used by applicators. This study was undertaken to determine which practices applicators consider possible and which they are willing to adopt.
In January, 1999, the Delaware Annual Pesticide Conference was held on "Pesticide Spray Drift Management." It was attended by 239 applicators, educators and regulators. David Esterly presented "Summary of Spray Drift Task Force Pesticide Registration Work" and the video "Straight Talk about Minimizing Spray Drift" was shown. At the end of the conference, applicators were instructed to complete the 3-part NCR evaluation form, "Put Safety into Practice!" This evaluation form was validated in 1997 through face-to-face interviews using an instrument with an ordered Likert Scale as described by Whitney (2000). On the evaluation form, applicators listed three new practices that they could use in their work to prevent pesticide drift. They gave two copies of the form to the conference organizers and retained one copy for their records. A total of 204 completed forms were collected from the audience.
In January, 2000, 196 of these forms were determined to be suitable for study and were returned to their authors. Applicators were instructed to check those practices that they used at least once since training and those that they adopted as routine. Procedures for maximizing return rate were used (Whitney, 2000). Evaluations returned to the University of Delaware numbered 148. Twenty-three of these were discarded because of post office returns or because the applicator did not apply pesticides during the year, leaving 125 forms.
Results and Conclusions
Of the 125 returned forms, two applicators indicated that they neither used nor adopted new practices, seven used at least one new practice at least once and 116 adopted at least one new practice. The116 applicators listed 332 practices that they pledged to adopt. These practices were coded for 15 categories as shown in Table 1. More applicators pledged to monitor wind speed than any other practice. Many applicators determined that they could change or adjust nozzles and change droplet size. Some applicators felt that they could change pressure, use adjuvants, or adjust the boom height. Few applicators indicated that they would set up buffer zones, avoid sensitive areas, spray at a different time of day, adjust their speed, or change the volume.
A chi-squared test of homogeneity was conducted on the top six practices as shown in Table 2. Eighty-eight per-cent of the applicators who wanted to monitor wind speed were able to change practices and do so, 84% changed pressure and 81% adjusted boom heights. However, only 70% of the applicators who pledged to change or adjust their nozzles did so and even fewer took measures to change droplet size (67%) or use adjuvants (65%). The chi-squared test indicated that there are differences among these six proportions of adoption. From this study it can be concluded that applicators do not adopt certain spray drift minimization practices as readily as others.
Barriers to adoption of new practices are often knowledge, cost, equipment, or time. The results of this study can be used by educators to help applicators get the knowledge they need to use more drift reduction measures beyond monitoring wind speed. This information can be used by pesticide registrants to encourage drift reduction. For example, If changing pressure or boom height will reduce drift of a certain pesticide, registrants may choose to put those requirements on the pesticide label and be confident that most applicators can and will adopt these practices. The pesticide industry needs to examine the reluctance of applicators to adopt changes in nozzles and use of adjuvants. More information is needed about the barriers to adopting these measures before strategies to overcome the barriers can be designed.
Whitney, 2000. Validation of an instrument to measure behavior change as a result of Pesticide Applicator Training. http://www.udel.edu/pesticide/measurechange.htm
The University of Delaware College of Agricultural Sciences statistician, John Pesek, gave advice on statistical analysis of this study.
This document appears at http://www.udel.edu/pesticide/drift.htm
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Susan P. Whitney: email@example.com