Effectiveness of Intercropping and Staking in the Management of Root-Knot Nematodes for Rural Farmers in Intensive Mixed Vegetable Cropping Systems in Southwestern Nigeria

Abstract

Two-season field trials were conducted between 2004 and 2006 at the vegetable research plots of the National Horticultural Research Institute Ibadan, Oyo state,
Nigeria to evaluate the effect of intercropping Telfairia occidentalis cv.EN2000-25 with okra cv. NHAe47-4 and pepper NHV!A on the populations of nematode pests of these vegetables. Raised seedlings of root-knot nematodesusceptible T. occidentalis and root-knot nematode-tolerant pepper varieties were each nursed and transplanted at 2 and 6 weeks respectively. Okra seeds were sown directly after transplanting Telfairia and pepper. The experimental layouts was in each case a 4 x 2 factorial fitted into a randomized complete block design with three replications. Sole cropping of Telfairia served as the control treatment. The result shows significantly high populations of the nematodes in sole Telfairia plots, Telfairia/okra as well as staked and unstaked Telfairia/okra/pepper mixtures. Lower populations of the nematodes in the soil and roots of plants as well as the number of eggs were observed in Telfairia/pepper intercrop. Root- knot rating was also significantly lower. Sole Telfairia and Telfairia/pepper intercrop recorded the highest shoot yield. Pod weight was heaviest in Telfairia/pepper intercrop. Yield of okra was significantly different in staked Telfairia/pepper/okra mixtures while the lowest value occurred in unstaked Telfairia/okra intercrop. The number and weight of pepper fruits in Telfairia/pepper intercrop was superior to the values observed in Telfairia/pepper/okra mixtures. The interaction between ropping system and staking method indicated that Staking x Telfairia/pepper intercrop exerted the highest suppressive effect on Meloidogyne incognita populations while Telfairia/okra and Telfairia/pepper/okra x staking interaction encouraged both soil and root nematode population build-up. The interactive effect of cropping system and staking method showed significantly highest shoot and pod weight values in staked Telfairia/pepper intercrop. The land equivalent (LER) and umulative yield of the crops was significantly highest in staked Telfairia/pepper intercrop when compared with other crop mixtures. This study therefore shows that using resistant/tolerant varieties as component crop in Telfairia production could be a useful approach in root knot nematode management under rural and farmer friendly intensive cultivation where these  vegetables are mostly preferred.