Economic Model Labelling

During 1995-1997, the information from past studies, almost 5000 field trials, new surveys of growers, and a weed control model developed by Dr. David Bridges (Bridges, 1998) were used to provide USEPA with estimates of the economic benefits of triazine and atrazine on all crops labeled with these products in the United States. A summary of the economic and biological models and some of the components are available (Bridges, 1998 Carlson, 1998). 

In the past, industry sold most pyrethroids as isomer mixtures however, in recent years the active isomer or isomers are being made and sold under different, but similar product names (e.g., biopermethim, cismethrin, bioresmethrin, and deltamethrin). This reflects the fact that the manufactures were able to economically produce one, or primarily one isomer. It is, therefore, reasonable to now develop PBPK models for these active isomers, rather than to try to construct them to only reflect the metabolism of mixtures. As a result of our having reviewed the metabolism of the 15 pyrethroids of interest in this paper, we have attempted to point out the isomers of each product that were studied (e.g., labeled with " C), and to provide their relative insecticidal activities. In Appendix D, Tables D1-D15, we... 

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