FIELD ASSESSMENT OF THREE BOTANICALS IN THE CONTROL OF ANTHRACNOSE DISEASE OF COWPEA CAUSED BY Colletotrichum truncatum

Abstract

Anthracnose disease of cowpea caused by Colletotrichum truncatum is known as a destructive pathogen that affects the production of cowpea worldwide (including Nigeria). The use of chemical fungicides for the control of this disease has been confirmed to be harmful to human health as the chemical finds its way into the cowpea seeds. This study is therefore focused on the assessment of three botanicals (neem, bitter, and tobacco leaves) to control anthracnose disease of cowpea on the field. This assessment was carried out with a susceptible variety to anthracnose (Ife brown) using three botanical extracts at three different concentrations (25, 50, and 75 %) and three times of application (before flowering, after flowering and before and after flowering). Ridomil gold was used as a standard chemical fungicide, and a control treatment without application of the extract was used as the basis for comparison. Inoculation with C. truncatum was done two weeks after planting. Botanical extracts were applied according to the treatment combination (extract concentration and time of application) as when due. Data were collected on disease incidence, disease severity, severity ratings, and seed yield per plot. The result showed that neem leaves at 75 % concentration and applied a week before and a week after flowering reduced disease incidence and severity on the field with an eventual increase in yield when compared with the control. Tobacco and bitter leaves were also effective as they showed better performance than the control treatment. The three botanicals showed promising levels of control as concentration increases and at different times of application.