- Presented at the 72nd Annual Meeting of the Western Society of Weed Science.
- Cover crop establishment for producers of non-transgenic sweet corn in western Oregon is challenging after harvest, particularly for late planted corn, or if fall rains begin early. Drilling cover crop seed between corn rows mid-season is one option, but without the option of glyphosate to control weeds postemergence, weed control may suffer. Three 4-HPPD herbicides are currently available for use in sweet corn for broad-spectrum postemergence weed control that have short soil residual and may be compatible with interseeding of cover crops. The objective of this research was to evaluate cover crop establishment and productivity, weed control, and sweet corn yield when applying tembotrione or topramezone at the same time that cover crops were drilled or broadcast seeded at V4, V6, or V8 in sweet corn. Applying tembotrione or tembotrione when interseeding cover crops by both drilling and broadcasting at V6 optimized weed control and cover crop growth. Interseeding at V4 reduced corn yield because of competition from the cover crop. Spring oat, triticale, and crimson clover growth were unaffected by tembotrione or topramezone, whether the cover crops were drilled or broadcast on the soill surface. Applying tembotrione, topramezone, or tolpyralate when cover crops are interseeded into sweet corn may be a viable strategy to improve cover crop establishment without sacrificing weed control.