Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu
SCN was diagnosed this past week in soybeans and snapbeans. These two hosts are the only crops that are affected in the region. If you see stunting and yellowing, carefully dig up the affected plants with a shovel or trowel and gently shake the soil from the roots. White or yellow females will be seen attached to the infected roots if present. They are small, much smaller than the nitrogen fixing nodules, but can be seen with the naked eye. A 10x hand lens makes the task much easier to see the lemon shaped females. Don’t presume that all the stunting that can be seen is due to water-logged soils or compaction. If it is not clear what the problem is or if cysts cannot be seen, a soil sample of the affected area can be taken and checked for SCN or other nematodes. Test bags and more information is available at the County Extension offices and forms and info at the Plant Diagnostic Lab site at http://ag.udel.edu/extension/pdc/pdf/Nematode_Assay_taking_samples.pdf.
