Neem extract as bio-pesticide is effective in reducing insect pest populations. However, farmers lack information on the effective application rate. The study ascertained the effective neem extract concentration for reducing insect vector numbers, incidence and severity of the viral diseases. Three rates 20, 30 and 40 ml/L of neem extract, commercial pesticide Akape® and water as control were sprayed as treatments on field grown three okra varieties F1 Sahari, F1 Kirene, and Asuntem. The populations of flea beetle and whiteflies as well as the incidence and severity of Okra mosaic virus (OkMV) and Okra yellow vein mosaic virus (OYVMV) were monitored. 20 ml/L produced significantly (p < 0.05) the lowest flea beetle and whiteflies count. The 20 ml/L rate also caused significantly (p<0.05) the lowest severity of insect pest damage and the least severity of OkMV and OYVMV diseases in all three okra varieties. Importantly, a yield of 207 kg/ha from the okra variety F1 Kirene obtained at the rate 20 ml/L was the highest (p>0.05) compared to the other neem extract concentrations and okra varieties. The cultivation of F1 Kirene could be combined with 20 ml/L neem extract to obtain effective disease and pests control for good yield.

Keywords: Chemical control, flea beetle, pests and diseases, plant protection, whitefly, yield loss