Effects of Sunn hemp (Crotalaria juncea) and Mexican sunflower (Tithonia diversifolia) soil amendments on yields and quality of two indigenous vegetables grown in a nematode-infested field

Abstract

Two separate sets of field trials were conducted in 2016 and 2017 to determine the effects of sunn hemp, Crotalaria juncea and Mexican sunflower, Tithonia diversifolia on yields of Amaranthus cruentus and Solanum macrocarpon grown in fields infested with Meloidogyne incognita, Rotylenchulus spp. and Xiphinema spp. Eight week-old seedlings of sunn hemp and Mexican sunflower were incorporated into the soil at 10 and 20 seedlings/plot each four weeks after transplanting. Plots where sunn hemp or Mexican sunflower was not incorporated served as controls. Data were collected on soil nematode populations and yields of the vegetables/plot. The results show that incorporation of sunn hemp and Mexican sunflower each at 10 and 20 seedlings/plot on nematode-infested fields sown to A. cruentus and S. macrocarpon significantly reduced the populations of M. incognita, Rotylenchulus and Xiphinema spp. and increased the yields of the vegetables in comparison with fallow control plots. Incorporation of sunn hemp and Mexican sunflower at 10 or 20 seedlings/plot could provide effective management strategy for plant-parasitic nematodes.