Aircraft Calibration for Pest Eradication Operations Using Pesticides Formulated as Solid Baits

摘要

The objective of any aerial (or ground-based) pesticide application is to achieve a biological objective while minimizing costs and environmental and social impacts. A requirement for achieving this objective is to spread the material at a preset rate and at an acceptable uniformity while minimizing the total aircraft travel distance and operation time, which equates to cost. The aircraft calibration procedure is an important step in developing operational parameters to meet these criteria. Many factors influence the variability of pesticide deposition during a calibration procedure. However, the calibration process is actually designed to minimize much of this variation. Therefore, pesticide deposit variation during an operation is likely to be significantly higher than expected from the calibration process. The consequence of variable deposition is overdosing and underdosing. Underdosing is a particular concern for a pest eradication operation because survivors could re-establish the population.A new modeling approach proposed for aircraft calibration more accurately quantifies the level of deposit variability likely to result from different operational specifications. Using an operational mosquito eradication program as a case study, the newanalysis highlighted that, for this scenario, the proportion of the target area underdosed was not extremely sensitive to either the sampling area size or the lane separation. Nevertheless, reducing the lane separation to 18 m from the current specification of 20 m reduced the predicted underdosed area by about 2% to 3% depending on the target area size (sample area). Without further analysis, the trade-off between a 2% to 3% reduction in underdosing (i.e., the probability of eradication) versus an increased operational cost from increased flying time is a subjective decision. A significant result was the very high sensitivity of the underdosed area to the standard deviation of wind speed. This result means there is a large advantage in maintaining a low wind speed during the application.