Effects of Two Types of Fertilizer and Arbuscular Mycorrhiza on Damping off Disease ( Macrophomina phaseolina ) of Cowpea ( Vigna uniguiculata L. Walp)

A screen house experiment was carried out to determine the effect of organic fertilizer, compost, inorganic fertilizer, and single super phosphate and Arbuscular mycorrhiza on damping-off disease of cowpea. The experimental design used was completely randomized design (CRD). There were fifteen treatments which were replicated three times. 2g of Macrophomina phaseolina (damping off disease) was infested on 10kg of soil sample in each pot with (30 by 75) cm spacing. Arbuscular mycorrhiza , compost (poultry based) and single super phosphate (SSP) were applied at the rate of 2250kg/ha, 1670kg/ha and 676kg/ha respectively. Three seeds of cowpea were sown into each pot, but later thinned into two plants per pot. Data on germination percentage at 7, 14, 21 and 28 days, number of leaves of cowpea at 2, 4, 6 and 8 weeks after planting, weight of pods per plant, incidence and severity at which pathogens affected the cowpea plant per treatment and growth yield of each treatment were collected and analyzed using analysis of variance (ANOVA) and means separated using the Duncan multiple range test. The plants that were treated with 676kg/ha single super phosphate produced higher cumulative weight of harvested fruits per plant followed by Arbuscular mycorrhiza , which did not have any negative effect on environment. The values of phosphorus in the post harvest soil analysis revealed that lower values of phosphorus were recorded in Single Super Phosphate treated pots, while plants treated with Arbuscular mycorrhiza at 500kgha -1 produced higher P value than the pre-planting soil analysis indicating the absorption of large amount of the elements. It was therefore recommended that Arbuscular mycorrhiza could be used to optimize seed yield in cowpea.