Efficacy and Gross margin analysis of carbofuran on nematode management in three cultivars of cowpea (Vigna unguiculata (L) Walp)

Abstract

Field trials were carried out in 2000, 2001 and 2002 to study the efficacy of applying carbofuran at 0 kg a.iЛha; 2.4 kg a.i/ha; 3.0 kg aiha and 3.6 kg a.i/ha in the management of nematode populations in the production of three cowpea cultivars: Ife Brown, JT90K- 277-2 and a local premium 'Oloyin'. The 4x3 field trials were laid out in a randomized complete block design replicated three times at the Institute of Agricultural Research and Training sub-station, Ikenne and University of Agriculture (UNAAB) Teaching and Research Farm Abeokuta. Soil nematode population densities were assayed using the Whitehead and Hemming tray method prior to planting and at the end of each experiment. Data collected on number of days to 50% flowering, number of seeds/pods, 100- seed weight, nematode populations and grain yield were subjected to analysis of variance, correlation, and cost-benefit analysis with means separated using Duncan Multiple Range Test. Results obtained revealed the presence of economically important plant parasitic tematodes in the two locations, Meloidogyne juveniles, Pratylenchus, Rotylenchulus reniformis and Helicotylenchus species being the host common. Application of carbofuran significantly reduced number of days to 50% flowering by 2-5 days. The relationship between treatment and nematode population was inversely proportional such that the lower the nematode population density the higher the grain yield and vice versa. Nematode population densities were significantly reduced at the lowest 2.4 kg a.i/ha rate of arbofuran with further significant reduction at 3.0kg a.i/ha. The least nematode infested variety was the IT90K-277-2 which recorded te lowest number of days to 50% flowering, highest number of seeds/pods and consequently yielded more grains than Ife-Brown and Oloyin varieties. Cost- benefit analysis indicated higher monetary returns of N 3.851.00kN 21,512.50k difference in profit tributable to carbofuran treatments compared to the control at all levels of application.