Pesticidal evaluation of teak and almond ethanol leaf extracts against two insect pests of sweet potato (Ipomea batatas L.)
Keywords:Sweet potato, synthetic chemicals, botanicals, Phyllotreta cruciferae, Cylas puncticollis, plant extracts
The cultivation of sweet potatoes is constrained by insect pests. This had led to the use of synthetic insecticides which are unsafe for humans and the environment. Although various studies have investigated the single application of plant material to control pests, this study employed the combination of two botanicals to suppress them. The aim was to evaluate the pesticidal effectiveness of teak and almond ethanol leaf extracts against Phyllotreta cruciferae and Cylas puncticollis infesting sweet potato. The experiment was arranged in a randomised block design with three replications. The various treatments employed were single applications of almond (AL) and teak leaf (TL) extracts at 15% and 25% concentrations; mixed application of AL and TL extracts at AL15% + TL15%, AL15% + TL25%, AL25% + TL15% and, AL25% + ATL25% respectively, cypermethrin (0.15%) and a control. Data were collected on the number of the insect pests after treatments, sweet potato yield, and phytochemical screening of the botanicals. Analysis of variance indicated that the combination of AL and TL at 25% each significantly (P ≤ 0.05) lowered the population of insect pests to a level comparable to cypermethrin and lower than the single applications of the botanicals. There was a significant increase in yield on plots treated with AL + TL at 25% concentration each. Phytochemical analysis indicated the presence of some bioactive compounds in the botanicals. The combination of different botanicals may be a plausible sustainable alternative to synthetic pesticides in pest management.