The Effect of Some Plant Extracts on Root-knot Nematode Meloidogyne incognita Populations on Pepper and Tomatoes

The root-knot nematode, Meloidogyne incognita, is one of the major pathogen causing great losses in many crops worldwide. Nematicidal activity of five plant essential oils (onion, QL agri35, bay tree, eucalyptus, mustard) against M. incognita were investigated in tomato and pepper. Experiment was designed as randomized complete block design with three nematode inoculums (0, 1000 and 2000 J2 per plant) and three essential oil concentration (0, 100 and 250 mu L per plant) replicated four times. There were no significant differences between nematode inoculums level and essential oil concentration used. However, all plant extract treatments restrained nematode populations in both tomatoes and pepper host plants. Among the essential oils, eucalyptus sustained the highest plant heights of 34.20 +/- 2.9 cm and 29.55 +/- 3.4 cm for tomato and pepper, respectively. Among all treatments, eucalyptus reduced the number of second-stage juvenile in the soil (Rf) significantly in both tomatoes (0.70 +/- 0.1) and pepper (0.10 +/- 0.2). Among five plant essential oils, application of a rate of 100 mu L per pot could give the best results in root-knot nematode control and be an alternative to the some current control methods. Further studies are needed in the area of using plant extracts as an alternative to other nematode control tactics.