Effect of essential oils on mortality, hatching and multiplication of root-knot nematode, Meloidogyne incognitaand its Impact on plant growth parameters

Essential oil from aromatic plants showed strong nematicidal activity in vitro experiments. Among six tested essential oils, percent juvenile mortality was observed in lemon grass (Cymbopogon citratus), 89, 51 as well as in palmarosa (Cymbopogon martini), 80 and 44 at the doses of 500 and 250 ppm respectively at 12 hour of exposure time. However, maximum mortality percentage was observed in C. citratus oil and it registered cent percent mortality at 500 ppm at 24 hours of exposure time. The hatching in both treatments started by 8th day and steeply increased in 10th day. Essential oils at 5 concentrations drastically reduced the total number of J2, as both essential oils showed more than 50% reduction in hatching over control. The minimum cumulative hatching was observed in 1000 ppm in C. citrates oil. The effect of root-dip treatments of tomato seedlings with C. citratus and C. martini significantly reduced total number of root knot galls/per plant, per cent galled area and soil population as compared to control. The minimum number of M. incognita galls was found in C. citratus at 500 ppm it was significantly different from carbosulfan as well as C. martini treatments. The maximum shoot length was found in C. martini followed by C. citratus and carbosulfan at 500 ppm. All the treatments significantly improved the root length than the inoculated plants but they were not significantly different among themselves.