should not be confused with the small nodules on the roots of leguminous plants such as peas, beans, clover and lucerne. these nodules develop as a result of the presence of beneficial nitrogen-fixing bacteria. true root nodules of this type are readily detached and are pink or green inside.
root knot nematodes cause losses in potato crops by disfiguring the tubers. infection shows up conspicuously as pimple-like outgrowths on the skin, and the whole surface may become warty and discoloured. if one of the pimple-like outgrowths is cut open, the nematode may be seen using a magnifying glass as a small, glistening body embedded in the tissue.