Evaluation of the Windows Pesticide Screening Tool (Win-PST) for use in Hawaii

Michael Robotham, Tropical Technology Specialist

January 9, 2003

SUMMARY

The NRCS Pest Management Policy adopted in November, 2001 (Title 190, General Manual Part 404) requires that Pest Management Plans meeting Conservation Practice Standard 595: "Pest management" be developed where appropriate as part of RMS-level Conservation Planning.

The NRCS Water and Climate Center (WCC) has developed the Windows Pesticide Screening Tool (Win-PST) to help conservation planners to identify potentially intermediate and high risk situations that require mitigation measures. This computer-based tool has been tested and validated for mainland conditions; however, Hawaii technical staff expressed concern about its applicability to Hawaii soil and climate conditions and, by extension, to conditions elsewhere in the American Tropics. To that end, I conducted an evaluation of the accuracy and applicability of the Win-PST model for Hawaii.

The evaluation consisted of three components:

1. Comparison of the scope and content of Win-PST and the Comprehensive Leaching Risk Assessment System (CLERS) decision support system based on the Revised Attenuation Factor (ARF) leaching risk assessment model developed at the University of Hawaii and currently used by the State of Hawaii Department of Agriculture
2. Comparison of Win-PST predictions and CLERS predictions for common pesticides on major agricultural soils.
3. Comparison of results from both models to available field data on pesticide movement.

Win-PST predictions were found to be significantly positively correlated with CLERS predictions for a sample of 38 commonly used pesticides on 7 major agricultural soils on the islands of Oahu and Maui. Results of both models compared favorably to the available field data available. Win-PST provided additional information not included in CLERS including more soils, more pesticides, and pollution risk estimates from surface soil and water runoff. In addition, national support is available for Win-PST from NRCS-WCC.

In summary, I recommend that NRCS-Hawaii adopt Win-PST as a pesticide pollution risk assessment tool for use in conservation planning at this time. However, additional research is needed to determine the accuracy of Win-PST risk ratings under Hawaii-specific conditions, particularly volcanic ash soils with high organic matter content in sub-surface layers.

< Back to ... Programs