Host Suitability of Crops under Yam Intercrop to Root-knot Nematode (Meloidogyne incognita Race 2) in South-Western Nigeria

Twelve crops commonly grown in association with yam in South-Western Nigeria were evaluated for resistance to root-knot nematode Meloidogyne incognita (Kofoid and White 1919) Chitwood 1949, race 2 infection using the quantitative modification by Sasser et al. (1984) of host suitability designations of Canto-Saenz (1983) for plants infected with root-knot nematode in 1998 and 1999 planting seasons. Observations, based on gall indices and recovery of the juvenile larvae from the roots and soil indicated that Abelmoschus esculentus, Corchorus olitoris cv Angbadu and Sphenostylis stenocarpa cv Nsukka Brown were highly susceptible, while Arachis hypogaea cv UGA 4, Cajanus cajan cv Cita-2, Cucumis melo cv Bara To139, Manihot esculenta cv TMS 30572, Sorghum bicolor and Zea mays cv DMR-LSR-Y were hyper-susceptible to Meloidogyne incognita race 2 with reproductive factor and gall index of ≤1 and ≥2 respectively. Crotalaria juncea, Mucuna cochinchinensis and Stylosanthes gracilis were resistant to Meloidogyne incognita race 2 with reproductive factor and gall index of ≤1, ≤2 and ≥2 respectively. These intercrops if planted on yam mounds will play a prominent role in altering the populations of root-knot nematode Meloidogyne incognita race 2