INTERACTION OF DIFFERENT POPULATION LEVELS OF MELOIDOGYNE INCOGNITA AND FUSARIUM OXYSPORUM F. SP. TRACHEIPHILUM RACE 1 ON COWPEA

Abstract

Interaction of Meloidogyne incognita and Fusarium oxysporum f. sp. tracheiphilum race 1 was investigated in the screenhouse on cowpea cultivars Ife Brown and TVu 990 which are respectively susceptible and resistant to both pathogens. Ife Brown was infected earlier and more severely than TVu 990 by both pathogens acting either singly or in various combinations and at all concentrations tested.

When both pathogens were present together. there were decreases in fresh root and shoot weights of both TVu 990 and Ifc Brown cowpea cultivars as the inocula increased. Generally, increases in fungal concentrations resulted in decrease in galling especially in the Ife Brown cowpea cultivar.

Wilting was more pronounced on Ife Brown than on TVu 990. Infection occurred on TVu 990 only at very high nematode population and fungal concentrations. TVu 990 plants did not show any external signs of wilting 42 days after inoculation. But it took just 16 days for the Ife Brown cowpea cultivar to wilt at the highest combined inocula levels. Increasing the nematode population significantly increased the possibility of Fusarium colonizing and producing symptoms on the resistant cowpea cultivar.