Evaluation of the Efficacy of Locally Available Plant Extracts for the Control of Diamondback Moth (Plutella xylostella) on Cabbage in Abia State, South East Nigeria

The diamondback moth, Plutella xylostella, is the most economically damaging pest of brassica vegetables globally, notorious for rapid insecticide resistance development. In Abia State, cabbage farmers often rely on synthetic pesticides that are costly, hazardous, and increasingly ineffective. This study evaluates the efficacy of botanical extracts from three locally available plant species, namely Azadirachta indica (neem), Chromolaena odorata (Siam weed), and Allium sativum (garlic), against P. xylostella larvae on cabbage in Abia State. A field experiment will be conducted at the Abia State University Teaching Farm using a randomized complete block design with five treatments including a synthetic insecticide positive control and an untreated negative control. Larval counts, leaf damage scores, and plant growth parameters will be recorded weekly over eight weeks. Extract concentrations will be standardized at 5% and 10% dilutions. Data will be analyzed by ANOVA with means separated by LSD at p less than 0.05. The study hypothesizes that neem extract at 10% concentration will provide the most effective control among botanicals tested. Results will offer smallholder cabbage farmers in Abia State affordable, eco-friendly alternatives to synthetic pesticides. Keywords: diamondback moth, Plutella xylostella, botanical extracts, cabbage pests, Abia State