Interaction between Nematode Inoculum Density and Plant Age on Growth and Yield of Cucumber and Reproduction of Meloidogyne incognita

The profitable cultivation of cucumber is seriously threatened by root-knot nematodes. As the damaging effects of Meloidogyne incognita have not been assessed on cucumber, therefore, the present studies report the effects of five initial population densities of M. incognita on growth and yield of cucumber and nematode reproduction. All inoculum densities caused significant reductions in growth and yield of cucumber and were found to be positively correlated with the latter. On the other hand, ages of plants at inoculation had negative correlations with reductions in these parameters at each inoculum density. The production of galls was found to be positively correlated with the inoculum densities and plant ages. However, rate of nematode build up decreased with an increase in inoculum density and appeared to be negatively correlated with inoculum densities and, on the contrary, was found to be positively correlated with plant ages. The results demonstrated that M. incognita has the potential to severely impair the growth of cucumber and by delaying early exposure of the latter to nematodes can significantly abate yield losses.