Efficacy of aqueous extracts from three plants in controlling cabbage aphid [Brevicoryne brassicae L. (Hemiptera: Aphididae)] on field-grown cabbage (Brassica oleraceae L.)

Abstract

Cabbage (Brassica oleracea var. capitata L.) crops are frequently attacked by aphids (Brevicoryne brassicae L.) which severely damage cabbage production. This research was conducted at an experimental cabbage field of the Institute of Environmental Science, University of Rajshahi, Bangladesh, from 15 November 2020 to 14 February 2021. This study assessed the dose-dependent efficacy of aqueous extracts from the seed of jute (Corchorus capsularis L.), leaves of bottle gourd (Lagenaria siceraria Molina Standl.), and fruit peel of lemon (Citrus limon L. Osbeck), compared with the chemical insecticide Malathion. The experiment design was laid out in a randomized complete block design (RCBD) with three replications. One-way (ANOVA) analysis was performed on the acquired data and significant differences among treatments were detected using Duncan's Multiple Range Test (p < 0.05). This study revealed that bottle gourd leaf extract at 10% and 20% (w/v) concentrations resulted in high biopesticide activity against aphids and increased cabbage yield by 12%–13%, compared with the control. The application of 30% (w/v) bottle gourd leaf extract significantly decreased aphid infestation by 28.26% and 46.83% at 45 and 60 DAT, respectively in field-grown cabbage and led to a 30.95% increase in cabbage yield compared with the Malathion. Thirteen potential chemical components of the bottle gourd leaf extract were identified using gas chromatography–mass spectrometry analysis that may possess the insecticidal ability. Results indicated that bottle gourd leaf extract has great potential as an alternative to synthetic chemical pesticides in controlling aphids in cabbage in an environmentally friendly way.

Keywords

• plant extracts
• aphid
• cabbage
• bottle gourd leaves
• gc-ms