CALCULATION OF PESTICIDE RESIDUES ON ROSES USING CALIFORNIA'S TOTAL REPORTING DATA AND FIRST ORDER CHEMICAL KINETICS

Abstract

Questions may arise as to residual pesticide concentrations on rose plants because of worker health, customer health, or environmental concerns. A case study conducted on roses from the Wasco, CA, USA, area provided a framework for addressing this question through development of experimental data for rose plant surface area, followed by compilation of pesticide application data collected via California's total reporting requirement. Thirteen pesticides were used on the crop, some with multiple applications and up to four different rates. In the modeling portion of the study, pesticide residual concentrations were calculated using degradation rate data and first-order chemical reaction kinetics. Results indicated concentrations of pesticides were small on rose plant surfaces at time of respective applications, and vanishingly small at the time of harvest and subsequent sale. This modeling approach can be used to provide estimates of pesticide concentrations at various times following application, and is a relatively simple yet powerful tool for addressing questions of chemical concentration where residues of pesticides or other agrochemicals are of interest.