Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
9/27/99
Contacts:
Greg Tylka, Department of Plant Pathology, (515)
294-3201
Paula Flynn, Department of Plant Pathology, (515)
294-0581
Julie Todd, Extension Communication Systems, (515)
294-2405
New SCN Egg Extraction Technique Being Used For Soil Samples
AMES, Iowa -- The Iowa State University Plant Disease Clinic recently announced that it has begun using a new technique that increases the efficiency of extracting eggs from soil samples infested with the soybean cyst nematode (SCN).
SCN egg counts from soil samples processed with this technique will be 100 to 200 percent greater than in the past. For example, a soil sample with a reported density of 1,585 eggs per sample with the previous technique now will have an egg density of 4,225 eggs per sample.
ISU Extension nematologist Greg Tylka explains "Because of the substantial difference in the number of eggs recovered with the two techniques, a direct comparison of the results of samples from the ISU Plant Disease Clinic this year with results obtained from the Clinic in previous years cannot be made.
"It is very important for individuals who are monitoring their SCN population densities to not interpret increases in egg densities from samples submitted this year relative to samples from prior years as a true increase in nematode population densities," Tylka says.
The management recommendations and egg population density classifications reported by the ISU Plant Disease Clinic have been adjusted appropriately to account for the increase in effectiveness of the extraction technique. A notice explaining how to interpret the new SCN sample results is being attached to reports sent out by the Clinic.
ml: isufarm
Extension programs are available to all without regard to race, color, national origin, religion, sex, age, or disability.