The root lesion nematode causes a gradual decline and, if uncontrolled, a severe loss in production (quality as well as quantity) of greenhouse-grown roses. The disease progresses gradually; aboveground symptoms include lack of vigor, chlorosis, and generally sparse vegetative growth with shortened blossom stems. Diseased roots may have distinct small brown lesions at first, but these usually expand until they coalesce and the tissue deteriorates.

The authors gratefully acknowledge the cooperation of Paul Nielsen of Groen Rose Company, Goleta, California.