Nematicidal Properties of Moringa oleifera, Chromolaena odorata and Panicum maximum and Their Control Effects on Pathogenic Nematodes of Yam

A field study was conducted at Atonsu, Sekyere Central District, Ghana from 2013 to 2014, to (i)
determine the effects of Moringa oleifera, Chromolaena odorata and Panicum maximum as ex-situ
mulches, on soil nematodes population after two years of yam cropping and (ii) assess the effects of
the soil nematodes on the yield and physical tuber quality of yam. The field experiment was a 3x3
factorial arrangement in a randomized complete block design with three replications. The first factor
was ex-situ mulch types at three levels; Panicum maximum (farmers’ choice), Chromolaena odorata
and Moringa oleifera. The second factor was natural fallow aged systems at three levels: 3, 5 and 7
years old. Data collected included nematode population changes, total tuber yield of yam and tuber
physical quality assessment. Generally, Meloidogyne spp., Pratylenchus spp. and Scutellonema spp.
were the nematode genera identified. However, Scutellonema spp. was found to be the most
pathogenic nematode affecting yam tuber yield and physical quality. Chromolaena and Moringa
mulches suppressed Scutellonema spp. populations by 80.7% and 76.2% respectively as compared
to the Panicum maximum mulch. The suppressed Scutellonema spp. population significantly
contributed to higher tuber yields and good tuber physical quality under the M. oleifera and C. odorata
mulches in comparison to the P. maximum mulch.