Bio-efficacy of promising medicinal and aromatic plants against diamondback moth, Plutella xylostella (L.) on cabbage under field conditions

A field experiment was conducted during the summer season of 2019 (April-June) at a farmer’s field in Nellakunte, Doddaballapur taluk, Bengaluru Rural district to evaluate the bio-efficacy of selected medicinal and aromatic plant extracts against diamondback moth (Plutella xylostella L.) on cabbage. The experiment was laid out in a randomized block design with ten treatments and three replications. The results of the field trial clearly indicated the superior efficacy of 5 percent neem seed kernel extract (NSKE) against DBM on cabbage compared to the other plant extracts evaluated. The plant extracts such as pongamia, datura, bael, calotropis and hebbevu exhibited moderate effectiveness against DBM. Further, the plots treated with plant extracts recorded higher activity of natural enemies such as Cotesia plutellae and spiders compared to chemical insecticide treated plots, indicating the eco-friendly nature of botanical treatments. In addition, NSKE registered the highest cabbage yield and benefit-cost ratio (2.48), followed by datura (2.15), bael (2.05), tulasi (1.64), nagadali (1.41), hebbevu (1.35), pongamia (1.25) and calotropis (1.20). The study demonstrates that botanical extracts, especially NSKE, offer an effective and environmentally safe alternative for the management of diamondback moth in cabbage under field conditions.