Source: Pioneer Hi-Bred news release



Soybean growers have a better chance of controlling soybean cyst nematode (SCN) populations by rotating SCN resistance sources and planting non-host crops, say agronomy experts at Pioneer Hi-Bred, a DuPont business.



Using only one source of resistance may mean some SCN races aren't controlled. Combining soil testing to determine egg numbers and race along with the right Pioneer brand variety could go a long way in managing this serious soybean pest.



SCN, the single most damaging pest of soybeans, continues to spread in northern areas of the Corn Belt. Managing this pest requires scouting, sampling, and rotating crops and sources of SCN resistance.



"Soil sampling and rotating sources of SCN resistance act as a check and balance for growers," says Jim Boersma, Pioneer area agronomist based in Minnesota. "Growers can monitor SCN management by sending soil samples to their University nematode laboratory every few years. Rotating sources of resistance is vital to ensure one race or population of SCN doesn't become dominant."



To further understand the impact of SCN and its life cycle, Pioneer agronomists and field staff conducted multiple on-farm SCN trials in 2008. The goal was to compare the increase in SCN egg density for one growing season that occurs when three types of varieties are planted: nonresistant, PI88788 source resistant and Peking source resistant. Four varieties were planted in 25 different Minnesota sites: a Pioneer variety with the PI88788 source, a Pioneer variety with the Peking source, a Pioneer variety with no SCN resistance and a competitor's variety with the PI88788 source. The Peking and PI88788 are two sources of SCN resistance used by Pioneer soybean breeders to decrease the egg count of SCN.



"We found there is significant value using SCN-resistant varieties," Boersma says. "In non-SCN-resistant varieties tested, there was an average increase of nearly 10,000 eggs per 100 cubic centimeters of soil."



Soil was collected at each site within each variety plot in both the spring and the fall to measure the seasonal increase in egg density.



At the 25 locations, one of two Peking varieties was planted