Identification of Root-Knot Nematode Species Occurring on Tomatoes in Tanzania and Resistant Lines for Their Control

This was a 5-year study that included surveys during the first 2 years, followed by field evaluations of improved tomato lines over the next 3-year period. Surveys were conducted in 12 regions of Tanzania from 1993 to 1995 to identify the causal nematodes of tomato root-knots. Eighty-seven samples were collected and assayed for presence of Meloidogyne spp. M. hapla, M. incognita, and M. javanica were detected at incidences of 1, 19, and 89%, respectively. Species mixtures were common within samples. Results indicated the presence of races 1 and 2 of M. incognita in tomato-growing regions of Tanzania. Reactions of eight advanced tomato breeding lines to the three species in greenhouse and field tests indicated that three lines, namely ARP 365-2, 367-1, and 367-2, were resistant to M. incognita races 1 and 2 and to M. javanica, but all lines were susceptible to M. hapla.