Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu
Soybean cyst nematode can be seen on plants that are 32-35 days from planting. The recent dry weather can accentuate the damage from SCN. Look for areas in the field which are yellow and/or stunted. The small yellow or white cysts can be seen easily at this time if you have a 10X hand lens and carefully dig up the plants and do not pull them from the soil. Soil sampling is also encouraged if you do not find the cysts or to confirm their presence if you are not sure. Soil sample bags are available from the county Extension offices. Remember, if soybeans are being planted after barley and wheat it still is not too late to soil test for SCN, especially if you are not planting a resistant variety.
Small white female SCN and a large nitrogen fixing nodule for comparison. (SON)