THE ROOT-LESION NEMATODE, PRATYLENCHUS PENETRANS (COBB, 1917) FILIP. & STEK. 1941, IN CELERY

Pratylenchus penetrans, Meloidogyne hapla, and Paratylenchus hamatus were the predominant nematode species associated with the roots of celery in the Burlington area of Ontario. Pratylenchus penetrans was found associated with irregular areas of stunted celery and because of the orange color of the roots the growers called the condition "rusty" root. In growth room studies relatively large numbers of P. penetrans were required to produce stunting. The amount of growth was inversely proportional to the size of the initial nematode population. Pratylenchus penetrans can overwinter in celery root debris. Tomato, cabbage, lettuce, cauliflower, potato, and eggplant were also found to be hosts of P. penetrans.