Survey of Plant Disease Prevalence on Okra (Abelmoschus esculentus (L.) Moench) at Rivers State University

Survey of disease incidence and severity on okra (Abelmoschus esculentus (L.) Moench) was carried out to determine the geographic distribution and status of the diseases throughout Rivers State University. Three fields of okra were randomly selected and varied numbers of okra plant were observed and visually identified some disease symptoms associated with okra plant. Visual assessment method was used to estimate the qualitative and quantitative lesion that manifested on the plant stem and leaf. Percentage Ratio Scale for Visual Estimate of plant disease incidence and severity was adopted. Where the number of leaves/stems that were not diseased/infected was (0%), less than 10% infected (1), between 11-20% infected (3), between 21-39 infected (5), about 50-70% infected (7) and 71-100% infected (9). Inter-rating reliability/reproducibility of plant diseases between the observed fields was statistically determined using One-way t-Test analysis at 5% probability level. From the estimate, rust and ring spot occurred more frequently and had the highest percentage contribution of 14.0% each. Followed by leaf spot (13.1%), chlorosis and necrosis (9.2%), rot (8.3%), wilting (7.0%), mildew and scorch (6.7%) each, and curling (3.8%) which had the least percentage contribution of disease incidence in the fields. Result showed that disease severity/index of okra plants at the nearest minimum in the examined fields at Rivers States University was (25.2%).