An improved method for quantification of heterodera glycines in plant tissues

An improved maceration method with pretreatment of freezing roots was developed for extraction and quantification of the soybean cyst nematodes (Heterodera glycines) in soybean (Glycine max) roots. The roots were frozen at ?20C and thawed for two to three cycles to soften and break the tissues before being macerated with a blender, and then centrifuged in sucrose solution. The nematodes in different life stages extracted by this method without staining can be counted under an inverted microscope or a stereomicroscope. The nematode extraction efficiency with this method was approximately 95%. The number of nematodes determined by this new method was highly correlated with that determined by counting nematodes directly from stained roots under stereomicroscope, and the accuracy was also greater. This new method is reliable, efficient, and environmental friendly for quantifying nematodes from plant roots.