FIG. 8. NEMATODE ROOT KNOT. 



a. Root knot of Irish potato, b. root knot of onion, c. root knot of parsnip, d. 

 egg of nematode, Heterodera radicicola, e. young female worm, /. half-grown female 

 worm, g. young male worm, h. matured male worm ready to emerge from old body 

 covering, . matured female worm (d. to *. greatly enlarged, after Stone and Smith). 



