Incidence and severity of common viral and fungal diseases of dry season okra crop in the derived savannah of Nigeria

Abstract

 A field experiment was carried out on the Teaching and Research Farm of the Faculty of Agriculture, University of Ilorin between the months of January and April 2005 to survey the incidence and severity of some common fungal and viral diseases of dry season okra crop. Okra cv Clemson was planted under furrow irrigation. During the first 4 weeks after germination (i.e. seedlings/ vegetative stage) the highest incidence of single infection was fungal at 21.1% recorded by the end of the second week. At the second week, single viral infection was 5.9% while mixed infection was 3.2%. The trend with time however, was that of steady decrease in single fungal infection and correspondent increase in both single viral and mixed fungal and viral infections. By the flowering and fruiting stages at 6 weeks after germination, the percentage incidence of mixed infection was ca. 30% while fungal and viral alone stood at 16% and 13% respectively indicating aggravated infection of viral infection on already fungal infected plants. Considering, total incidence regardless of causal agents, stage I had total incidence of diseases at 30.2%, Stage 2 had 40.2%, while stage 3 had 58.8%. Over all, there was significant retardation in the growth attributes of diseased plants compared to the healthy ones with the mixed infected plants having the highest retardation.