Efficacy of aqueous leaf extracts of neem, bitterleaf and their mixture for prevention of smut and red rot diseases of sugarcane

Abstract

Sugarcane is the main source of sugar. Sugar production is greatly threatened by smut and red rot diseases caused by Sporisorium scitamineum and Colletotrichum falcatum, respectively. Although there are recommended chemical and cultural control measures for these dreaded diseases, the control measures have serious shortcomings as a result of which there is a need to evaluate the efficacy of aqueous leaf extracts of neem and bitterleaf as a control measure, the aim of this study. Sugarcane setts were inoculated with mycelial suspensions of Sporisorium scitamineum and Colletotrichum falcatum. The inoculated cane setts meant for pre-planting treatment with 30 g/100 ml leaf extracts of neem, bitterleaf and their mixture were soaked in each of the extracts for 30 minutes, dried, and then planted in plastic buckets containing sterilized soil. The inoculated cane setts for post-planting treatment were also planted in plastic buckets containing sterilized soil and sprayed fortnightly with 30 g/100 ml leaf extracts of neem, bitterleaf, and their mixture. All the plastic buckets were labeled appropriately and allowed to stand for 3 months, the incubation period for smut and red rot diseases of sugarcane. Pictures of the seedlings that sprouted from each of the inoculated cane setts showed the efficacy of 30 g/100 ml leaf extracts of neem, bitterleaf, and their mixture in preventing the occurrence of these diseases, with the post-planting fortnight spraying being more efficient. It is therefore recommended for prevention of smut and red rot diseases of sugarcane.