Keep Your Scouting Manual Handy

Wet start for corn could make for interesting year.

Published on: Jun 15, 2009

One year ago rain pounded the Eastern Corn Belt during the first half of June. This year some areas were hammered, but many areas just stayed wet. No matter where you farm, this has been a challenging start to the season form all accounts.

 

What happens from here on out will likely depend upon the weather. Warm, wet weather will favor certain foliar disease sin corn. Cool, wet weather would favor other diseases. If it turns extremely dry, soybeans become suspect to diseases such as charcoal rot, seldom seen in wetter years. And many fields could be affected by soil c0ompaction.

 

The need to get fields planted led to many fields being planted when conditions were 'sticky, but good enough to go.' After years of research, Gary Steinhardt, Purdue university Extension soil specialist, concluded that those are sometimes the conditions that produce the most soil compaction.

 

Whether that soil compaction translates into trouble for crops and eventually affects yields this year depends upon what happens in the weather department. Steinhardt discovered in the '80's that if it continues to rain enough to supply crops with adequate moisture, even crops with roots limited by soil compaction may be able to produce good yields. However, if a dry spell comes along, those may be the first fields to show the effects. His work also concluded that corn tends to show more impact form soil compaction than soybeans, both during the growing season and in the combine hopper at harvest time. But that doesn't mean soybeans are immune from impacts of soil compaction.

 

Dave Nanda will watch for development of leaf diseases and nutrient shortages when he walks fields this year. Nanda, who was consultant for the Corn Illustrated project from the beginning, believes in scouting and finding a need to treat for a pest, say a fungus on leaves, rather than just spraying in advance.

 

Two years ago in the Corn Illustrated plots there was very little disease pressure early because the season was on the dry side, especially at the plot location. Fungicides in the high-yield plots helped on yield, but the difference wasn't dramatic. Fungicides help most on susceptible hybrids in years when diseases would otherwise become rampant and move above the ear leaf to top leaves, he notes. Nanda says the biggest yield loss from foliar diseases in corn happens when diseases start early, get a boost from the weather conditions favorable to that disease, and bloom in mid-to-late summer, knocking out top leaves. The uppermost leaves are the ones responsible for providing the sugars that comprise the biggest part of the corn yield.

 

His advice is to stay alert, beginning now. Scout fields. When you spot disease, don't panic. Instead, identify it using resource guides, then monitor its development. Apply integrated pest management guidelines to determine if spraying should provide an economic return, he says.