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SELECTING PLANT SPECIES FOR PESTICIDE REGISTRATION TESTS
Citation:
PFLEEGER, T. G., D. M. OLSZYK, G. KING, AND M. PLOCHER. SELECTING PLANT SPECIES FOR PESTICIDE REGISTRATION TESTS. Presented at SETAC 27th Annual Meeting, Montreal, QC, CANADA, November 05 - 09, 2006.
Description:
Current test protocols used by the US EPA for the registration of pesticides examines plant responses of 10 crop species but may not examine regionally important native plants or crops. In order to test the efficiency of current test protocols we selected six native plant species from the Midwest and compared their responses with common crop species using sulfometuron-methyl. The native species, selected based on their ecological importance, were big bluestem, Calico aster, nodding smartweed, tall
goldenrod, and purple top tridens. These species were compared to traditional test species, corn, soybean, oat, tomato and carrot, in a vegetative vigor test using sulfometuron-methyl. Plants were harvested 14 days after treatment to measure vegetative growth and visible injury. The native plants were equally or less sensitive to sulfometuron-methyl than the crops. The no effect oncentration (NOEC) for the native plants usually varied from 0.001 to 0.01 x FAR. The crops' NOEC was no higher than 0.002 for any parameter or species. Corn and soybean were the most sensitive crop species. Native plants EC25 values were more variable than crops. The wide range in
response of the native plants compared to the crops was not surprising given their varied size, form and slow growth compared with crop plants. These tests indicate that the current testing protocol may be effective for certain native plants. Estimating potential risks of pesticides to plants requires an evaluation of cross-species sensitivity, the potential for exposure, the proposed pesticide use area, and the environmental conditions present in that area.