Post-Emergent Herbicides May be Ticket

DES MOINES - May 14/02 - SNS -- Corn producers need to more strongly consider post emergent herbicides as a wed control option this year in areas with unusually dry soils and in those areas where the rain does not seem to want to stop, say agricultural specialists with Pioneer Hi-Bred International, Inc.

"It's been dry in parts of the country, and that means, in some cases, herbicides applied before planting might not take," says Joe Mayer, a Pioneer agronomist based in Pennsylvania. "A good post-emergent herbicide applied early can help tackle the weeds that were unaffected by a pre-emergent treatment."

"Weed control is always important, but this year, it's even more important because of the dry conditions," says Dan Berning, a Pioneer agronomist in Nebraska. "You want to get out there early and eliminate the weeds that are competing for the same moisture as your corn."

While dry weather is one reason to look at post-emergent herbicides, the wet rainy weather that's hampered planting over the last few weeks is another.

"With the prime corn planting time slipping away due to wetter weather, it may make sense for some growers to switch herbicide plans from a pre-emergence strategy to an early post-emergence strategy that offers the necessary contact and residual control," says Mayer. "Plus, by applying after planting, you don't have to guess which weeds will be a problem this year."

The key to good post-emergent control is not to wait until the weeds are tall and out of control. Rather, be ready to go within three weeks of planting. If corn was planted between May 1 and May 10, fields should be ready for a post-emergent application near the end of the month when the corn is three to four inches tall.

According to Berning and Mayer, a dependable post-emergent weed control program should include the following:

* Good control of the toughest grasses and broadleaf weeds, including foxtail species, wooly cupgrass, fall panicum, wild proso millet and field sandbur.

* Good contact control independent of rain plus season-long residual control with an activating rainfall.

* A wide window of application relative to corn growth so there is ample time to protect the crop from later-emerging yield-robbing grasses.

* Tank mix flexibility to provide opportunity for broad-spectrum broadleaf control.

* A company representative who is readily available to help identify weed challenges, answer questions and assist with application if needed.

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