SURVEY OF PLANT PARASITIC NEMATODES GENERA ASSOCIATED WITH SUGAR BEET PLANTATIONS IN DAKAHLIA GOVERNORATE

A survey of plant parasitic nematodes genera associated with the rhizosphere of seven sugarbeet cvs. Kawemira, Monte-bionco, Deprez-poly N, Sultan, Nejama, Athos-poly and Farida grown at five counties of Dakhlia governorate (Egypt) was carried out during the sugar beet growing season 2007/2008/2009. Nine nematode genera were recorded in the surveyed sugar beet fields. Based on their frequency of occurrence , these genera can be arranged in ascending order as follows : Meloidogyne (J2) (22.6%) , Trichodorus (19.8%), Hirschmanniella (13.4%), Helicotylenchus (10.4%), Tylenchus (6.5%), Pratylenchus (4.7%), Dorylaimus (3.4%), Rotylenchulus (1.7%), and Tylenchorhynchus (1.3%). Among the seven true nematode genera recorded, Meloidogyne and Trichodorus seemed to be the major pest of sugar beet plantations in this work. Meanwhile , clay soil with 413 out of 700 soil samples examined encountered the highest number of nematode genera (7) followed by loamy (5) and clay loam (4) .