Abstract

K. Osei, J. O. Fening , S. R. Gowen and A. Jama

Most African farmers could not afford the purchase of pesticides to control crop pest, alternatives such as the use of phytochemicals are most useful. For best results, sound recommendations are needed on the use of different antagonistic plants in controlling pest. In Ghana few reliable data are available on the potential of antagonistic plants to control nematode population. A field trial was conducted in the forest and forest savanna transitional zones of Ghana to evaluate the potential of four leguminous crops in suppressing nematodes population. Mucuna pruriens, Crotalaria spectabilis and C. retusa were antagonistic but Phaseolus vulgaris was a favourable host to the pest. M. pruriens did not gall and no egg masses found on roots. C. spectabilis and C. retusa recorded insignificant galling indices of 2.6 and 1.8 respectively. However, P. vulgaris was significantly affected by Meloidogyne incognita as expressed by the significantly higher gall and egg mass indices. In addition, nodulation was greatly reduced in P. vulgaris. Consequently, significant higher population of nematodes (an average of 600 J2/g-1 root) was recovered from P. vulgaris whilst lower population (an average of 50 J2/g -1 root) was recovered from M. pruriens. The growth and yield of okra following M. pruriens resulted in a significant 48% yield increase over the control and P. vulgaris treatments. M. pruriens recorded 31 and 38% yield increase over C. spectabilis and C. retusa respectively.