Interaction of the entomopathogenic nematode Steinernema masoodi and the root-knot nematode Meloidogyne incognita on tomato

Abstract

The effect of different population levels (100, 1000 and 10,000) of infective juveniles (IJs) of Steinernema masoodi was tested on the egg hatching and juvenile mortality of Meloidogyne incognita in cavity blocks containing distilled water. A population of 1000 or more IJs of S. masoodi caused significant inhibition of the hatching of eggs and induced mortality to juveniles of M. incognita. The effect of the entomopathogenic nematode (EPN) on root penetration by root-knot nematode (RKN) juveniles was studied using concomitant inoculation with 500 J2 or 15 egg masses of RKN and 500, 1000, 5000 or 10,000 IJs of S. masoodi. The tested population levels of the EPN resulted in significant and progressive decrease in the penetration of RKN J2 into tomato roots. The effect of the EPN on galling, reproduction and soil population of RKN and on the plant growth and yield of tomato was investigated using pre, post and concomitant inoculation with 2000 J2 of M. incognita and 1000, 5000 or 10,000 IJs of S. masoodi/plant in earthenware pots. The pre-inoculation with 10,000 EPN IJs caused 11-39% reduction in galling, egg mass production and soil population of RKN and 19-22% increase in plant dry weight and yield of tomato. Steinernema masoodi at 5000 IJs inoculum level markedly suppressed nematode pathogenesis irrespective of inoculation mode, but the effect was significantly less than that obtained with 10,000 IJs, whereas 1000 IJs did not produce significant effects (P ≤0.05) on nematode pathogenesis.