Parasitic Activity of the Root Knot Nematode Meloidogyne incognita in Okra in a Naturally Infested Field and its Suppression by Lecanicillium muscarium

The experiment was conducted in a grower's field naturally infested with Meloidogyne incognita in Layyah District. Six okra genotypes, including 19,224; 19,235; Pusa Swami; Ikra-1; Ikra-2; and Sabzperi China Red, were selected from our previous study according to their galling index and level of susceptibility. These genotypes were used as test genotypes for the interaction between M. incognita and the entomopathogenic fungus, Lecanicillium muscarium. The initial inoculum was measured before okra was seeded in the field. At harvest, the numbers of root galls, egg masses, and eggs per root system, the root weight, the final population of the second stage juveniles, and the reproduction rate were detected at the highest levels in untreated soil, whereas low numbers were encountered in soils initially treated with the fungus, L. muscarium. Meloidogyne incognita and other plant parasitic nematodes multiplied significantly more in untreated soil than in treated soil, which clearly indicated that L. muscarium effectively reduced the nematode infestation level in the soil.