"We got knocked over the head with it last year."

Gary Klaassen is referring to the SCN problem that clobbered his 60-70 clients in 1997.

"We could find the symptoms about everywhere," says Klaassen, a Pioneer sales rep in northwestern Iowa.

He knew there was SCN in his territory, but thought it was limited to a small area. Spotty plant yellowing in other areas was blamed on iron chlorosis, and growers planted chlorosis-tolerant varieties to combat it.

But the spots kept getting bigger, and last year the problem worsened when late-summer weather turned dry.

"The drouth enhanced our cyst nematode problem," he says.

After attending a scouting school at Iowa State University, Klaassen dug up plants and examined the roots with a magnifying glass.

"We found out what the real problem was," he states.

Clients who planted SCN-resistant soybean varieties last year got about 10 bu/acre higher yields than those who didn't.