Interaction of Cucumber mosaic virus with the root-knot nematode, Meloidogyne incognita, and effects of certain medicinal and aromatic plants on infected cucumbers

Abstract

Three experiments were conducted in a greenhouse to investigate the interaction of Cucumber mosaic virus (CMV) with the root-knot nematode, Meloidogyne incognita, in cucumber. In the first experiment, the effects of different inoculum levels of M. incognita (0, 100 and 1000 second stage juveniles per pot containing 2 kg soil), alone or in combination with CMV, were investigated on cucumber cv. Alpha Beta. Numbers of galls and egg masses of the nematode were greater on the roots of cucumber infected with the nematode alone than on those of plants inoculated with both the nematode and the virus. In the second experiment, the intercropping of cucumber with some medicinal plants was tested by planting them beside cucumbers. The numbers of juveniles of M. incognita in the soil were reduced (P ≤ 0.05) and there were no significant differences among the tested plant species, one medicinal (Ambrosia maritima) and three aromatic (Dianthus caryophyllus, Ocimum basilicum and Zinnia elegans). In the third experiment, amendment of the soil with leaf powders of the same plants reduced the numbers of galls and egg masses of the nematode in the roots of cucumbers. In all cases, the treatments reduced the concentration and number of local lesions of the virus and enhanced plant growth and yield.