This can result in a mis-diagnosis. Use a shovel and dig up the plant at the base. Remove the soil from the roots and examine them for cysts. Cysts will be initially white or yellowish in colour and upon maturity they become brown. Nitrogen nodules are often identified and confused as cyst but they are considerably larger than the cysts.
Cysts are the size of a pin-head or the point of a pen.
Let's learn from the United States situation were SCN has become the number one soybean disease with estimated annual losses of 70,000,000 to 80,000,000 bushels. These losses are significant since they equal Ontario's entire annual soybean production. Reluctance by U.S. producers to identify SCN and adopt integrated management systems for SCN have assisted in its spread south of the border. Remember that soybean cyst nematode can not be eradicated once it infests an area. We are identifying SCN in new areas and unfortunately it will continue to spread to soybean producing regions of the province.