ABSTRACT Root root-knot nematodes belonging to the genus Meloidogyne are widely distributed worldwide and they are considered the most important phytopathogens due to their impact on economic importance crops. In the present study, morphometric variations of populations of Meloidogyne sp. collected in different localities from provinces of Cotopaxi and Tungurahua. Additionally, the effect of different doses (1, 2 and 3%) of essential oils of Nicotiana glauca, Ricinus comunis and Brassica carinata for the control of Meloidogyne spp was evaluated. A negative control (tween) and a positive control (Nakar nematicide 1.5 ml/L) were used. Samplings were made in farms planted with tomato in El Tambo, Cunchibamba, Quillan Loma and Izamba (Province of Tungurahua) and in Patain, Rumipamba, Salache, and Santa Ana (Province of Cotopaxi). The extraction of the nematodes was done by using the Baermann...