Farmers could be losing nearly $200 per acre by continuing to plant soybean varieties that are becoming less effective at warding off soybean cyst nematode (SCN) damage, according to Iowa State University plant pathologist Greg Tylka. 

Most SCN populations in Iowa have developed increased levels of reproduction on soybean varies with PI 88788 SCN resistance after heavy usage over the past several years, Tylka  reports. 

In a field experiment in southeast Iowa last year, soybean varieties with PI 88788 SCN...