Infectivity and reproduction of Meloidogyne incognita (Kofoid and White) Chitwood on African yam bean, Sphenostylis stenocarpa (Hochst Ex. A. Rich) Harms accessions as influenced by botanical soil amendments
A screen house experiment was conducted to study the effects of amendment of soil with leaf powders of some plants at different levels (5, 10, 15, 20 and 25 t/ha) on the infectivity and reproduction of Meloidogyne incognita (Kofoid and White) Chitwood on African yam bean, Sphenostylis stenocarpa (Hochst Ex. A. Rich) Harms. The plants were neem, drumstick, lemon grass, African peach and rattle weed. Results showed that botanical soil amendments significantly (P ≤ 0.05) improved growth of plants and reduced reproduction of M. incognita on African yam bean in varying degrees. The effects of botanicals on growth of plants and nematode reproduction increased with increase in concentrations/ amendment levels, and were highest at 25 t/ha. Cymbopogon citratus produced the highest manurial properties as it supported greater vegetative growth of plants while Moringa oleifera was most effective in the reduction of reproduction and development of M. incognita in the roots. M. oleifera produced the least gall index and egg mass index of 1.0, though Crotolaria retusa also recorded egg mass index of 1.0. Results from this study are indicative of the fact that local farmers could apply these botanicals as fertilizers during cultivation to counteract the effect of root-knot nematode, and also to improve growth of crop plants but field trials are necessary before final recommendation.
Keywords: Infectivity, reproduction, African yam bean, Meloidogyne incognita, amendment