sealPurdue News

March 1997

NOTE TO JOURNALISTS: A sidebar about how to grow a poor stand of corn is at the end of this story.

Diagnose crop problems with records and exercise, expert advises

WEST LAFAYETTE, Ind. -- Diagnosing crop problems accurately or preventing future problems requires good records and presence in the fields, according to Robert L Nielsen, professor of agronomy and Extension corn specialist at Purdue University.

Although well-intentioned optimism may keep farmers from taking note, literally, of what is happening in their fields, when problems do arise such written records are critical.

"Attempting to conduct a post-mortem diagnosis during harvest in mid-October for a problem that occurred in midsummer is often impossible," Nielsen says.

He says the first step in troubleshooting crop problems is walking the fields. "There is no substitute for getting out of the truck and into your fields when it comes to successfully diagnosing crop problems," he says. "Get out there often. The important thing is to diagnose the problem as soon as possible, because the evidence often disappears as seeds or plants rot away. For example, wireworm damage to a corn kernel is impossible to diagnose after the kernel has rotted away."

Nielsen says such tours are especially important early in the growing season.

"Stand establishment -- germination, emergence and seedling growth -- is critical for ensuring maximum yield potential for most agronomic crops," he says. "Failure to successfully establish a vigorous, uniform stand of plants almost always limits yield from the very beginning of the season."

Nielsen says that comprehensive records of what is happening in the fields are critical to diagnose or prevent problems.

"Invariably, the factor that most limits a good crop-problem diagnosis is inadequate cropping records," he says. "So many times when I am in the middle of a field wondering about a crop problem, I have the feeling that I am missing a critical piece of the puzzle that would solve the problem in an instant."

The list of important items to record is long, because the list needs to be as complete as possible. Items to record may include

Tillage operations this year and last year. Pesticide applications this year and last

Soil sample analyses. Rainfall this year and previous year.

Previous crop. Planting dates.

Where different varieties were planted. Seed quality of the varieties planted.

Planting depth. Soil moisture before, during and after planting.

Soil temperature at planting. Temperatures in general after planting.

Pesticides applied to an adjoining field. Any additional pertinent information.

Finally, Nielsen recommends that producers get help as soon as possible when they notice a problem but aren't sure exactly what's causing it or what to do about it. "Use the expertise of your local county Extension educator, private crop consultant, industry agronomist, or university Extension specialist," he says. "Send samples to diagnostic clinics for diagnoses and recommendations."

Expert provides recipe for corn crop failure

WEST LAFAYETTE, Ind. -- With his tongue planted as deeply in his cheek as physiology will allow, Purdue University corn guru and professor of agronomy Robert L. Nielsen has developed a plan for growing a poor corn crop.

"Every year, I get a lot of phone calls from folks wanting to know why their neighbor's cornfields ended up with such poor stands," he says. "Because some of these folks seem so ecstatic about it happening to their neighbors, I figure they may want to know how to create their own crummy stand. Here's the recipe."

Main ingredients:

One field, poorly drained, no-till preferred

A corn hybrid of poor seed quality and low vigor


According to Nielsen, this recipe serves six: "A farmer, a corn dealer, an industry representative, a seedsman, an Extension educator and an Extension specialist."

Source: Robert L. Nielsen is on sabbatical this semester. E-mail at
Writer: Steve Tally, (765) 494-9809; e-mail,
Purdue News Service: (765) 494-2096; e-mail,

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