1. Dep. of Plant and Soil SciencesOklahoma State Univ. Stillwater OK 74078
2. Dep. of Entomology and Plant PathologyOklahoma State Univ. Stillwater OK 74078
3. USDA‐ARS Plant Science Res. Lab. Stillwater OK 74075
4. Dep. of Biochemistry and Molecular BiologyOklahoma State Univ. Stillwater OK 74078