Pathogenicity of Root Knot Nematode (Meloidogyne incognita) and its Effect on Yield of Cowpea [Vigna unguiculata (L.) Walp]

Background: Cowpea [Vigna unguiculata (L.) Walp.] is an important food legume in the drier region and an essential component of the tropics and subtropics for the cropping system. Heavy infestation of cowpea by root knot nematode Meloidogyne incognita led to early senescence of the crop. The experiment was carried out to determine the potential level and the extent of yield loss in cowpea due to root knot nematode. Methods: A pot culture study and a field experiment were conducted to determine pathogenic potential level of root knot nematode and to determine the yield loss in cowpea with various treatment of 10, 100, 1000 and 10000 freshly hatched juveniles. Result: The treatment with nematicide, Carbofuran 3G @ 3 kg a.i./ha, reduced the final nematode population i.e., 50.94% in soil, 46.12% on root and 46.51% decrease in root knot index. The present study revealed that 1000 J2/pot was the ETL level that reduced all the growth parameters of cowpea and avoidable yield loss of 15.78% was recorded in Ccowpea due to M. incognita.