Researchers studied how different rates, timings, and herbicide combinations affect weed control and corn growth using primisulfuron. They found that primisulfuron had low impact on corn but varied in effectiveness on different weeds. It worked well on johnsongrass when applied early or mid-season, but not for the whole season. It controlled giant foxtail best when applied early. Common lambsquarters and redroot pigweed were most effectively controlled with early applications. Combining primisulfuron with other herbicides improved control of these weeds, but reduced control of johnsongrass and giant foxtail in some cases.