Interactive effect of Pratylenchus thornei and Meloidogyne incognita on the growth of Hyoscyamus niger

Pathogenic potential of root lesion nematode, Pratylenchus thornei on black henbane, Hyoscyamus niger was studied alone and in combinaion with root-knot nematode, Meloidogyne incognita in a glasshouse pot experiment. Growth of H. niger was significantly suppressed by P. thornei at an initial population level of 1250 nematodes per 7.5 kg soil with a further increase in initial population (Pi), there was a corresponding decrease in growth of H. niger as compared to uninoculated plants. At equal Pi levels, suppressive effect of M. incognita alone on the growth of H. niger was more severe than the inoculation with P. thornei alone. When both the nematodes were simultaneously inoculated, reduction in growth was more severe in comparison to single inoculation with either of the two nematodes. Amongst all the treatments, or inoculation of M. incognita expressed the highest reduction in growth of H. niger. Final population of both the nematodes was significantly influenced by the time of inoculation.