The Biocontrol of Soil Transmitted Cercospora capsici with Lactobacillus plantarum

Abstract

Microbial diseases of pepper (Capsicum species) are the most significant factors contributing to the loss of this economically important vegetable crop. Leaf spot disease caused by Cercospora capsici is one of the major constraints to pepper production in Nigeria. The disease is reportedly introduced through infected seeds. However, the development of Cercospora leaf spot on plants propagated from fungicide-treated seeds suggests an alternative perennial source of infection and also necessitates the development of an efficient, safe control measure. C. capsici was isolated from infected pepper plant through the direct plating method and subsequently characterised. Treated pepper seeds (with L. plantarum) were planted in C. capsici inoculated soil, while the emergence, seedling growth parameters and severity of leaf spot were observed. The severity index of Cercospora leaf spot on pepper plants (observed at the 20th day after planting) was significantly lower on L. plantarum treated plant set (0.07) than on pepper without seed treatment. Seed emergence rate index increased from 11.11 to 15.33% /day of untreated to treated pepper seeds sown in infected soil respectively, while the mean emergence time of untreated seeds (8.32 days) was significantly higher in C. capsici infected soil. It could therefore be deduced that seed priming with L. plantarum improved the seedling vigor and resistance of pepper to leaf spot disease caused by C. capsici.