Comparative Evaluation of Some Botanicals and Carbofuran in the Control of Root-Knot Nematode, Meloidogyne spp. on Cowpea (Vigna unguiculata)

YAKUBU, L.B. AND IZUOGU, N.B.

Department of Crop Protection,

University of Ilorin, Ilorin, Kwara State Nigeria.

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Abstract: The nematicidal effect of leaves of three selected plants, Calotropis procera, Crotalaria retusa, and Hyptis suaveolens were compared with a  synthetic nematicide, Carbofuran 3G applied singly to control root knot nematode infecting cowpea. A ploughed, harrowed and ridged plot of land was divided into 3 blocks, each having 8 treatments but replicated 3 times in a randomized complete block design form to give a total of 24 subplots. All subplots received the same level of root knot nematode inoculation. The leaves of each test plant were applied at two rates (3.0 tonnes/ha and 1.5tonnes/ha) while the Carbofuran was applied at 3kgai/ha. All the test plant leaves applied at higher rates performed significantly higher (P=0.05) and were almost as effective as Carbofuran at 3kgai/ha in terms of plant height, leaf number, seed weight, and days to 50% flowering. At harvest, galling was significantly lower in Carbofuran treated plots. The control plants were most galled with poor yield. The lower rate of botanicals (1.5tonnes/ha) performed significantly better than control plants in suppressing the effects of root-knot nematode infecting cowpea. These suggest that the tested botanicals are effective in the management of root-knot nematode population. The application of the tested botanicals at 3tonnes/ha can be used as substitutes for Carbofuran or other nematicidal synthetic chemicals in controlling root-knot nematode population in farmlands.