1. Washington State University, Irrigated Agriculture Research and Extension Center, 24106 N. Bunn Road, Prosser, WA 99350.
2. University of California, Cooperative Extension, Santa Cruz County, 1432 Freedom Blvd., Watsonville, CA 95076.
3. University of California, Agricultural and Resource Economics, 2146 Social Science and Humanities, Davis, CA 95616.
4. Oregon State University, Department of Crop and Soil Science, 3017 Ag and Life Sciences Building, Corvallis, OR 97331.
5. USDAARS Horticultural Crops Research Laboratory, 3420 NW Orchard Ave., Corvallis, OR 97331.
6. Oregon State University, Department of Horticulture, 4017 Ag and Life Sciences Building, Corvallis, OR 97331.
7. Corresponding author, e-mail: soneal@wsu.edu.
8. University of California, Department of Entomology, 374 Briggs Hall, Davis, CA 95616.