Biopesticidal potential of wild sunflower leaf extract ( Tithonia diversifolia ) against green peach aphids ( Myzus persicae ) of pak choi

Abstract Pak choi ( Brassica rapa var. chinensis ), a leafy vegetable belonging to the Brassicaceae family, is widely cultivated for its nutritional value and economic relevance. However, green peach aphids directly affect plant nutritional status by feeding on plant sap which threatens the production. Plant-based extract offers potential pesticidal compounds that can suppress pest infestation. This study evaluated the biopesticide effectiveness of Tithonia diversifolia leaf extract (WSLE) at different concentrations against green peach aphids ( Myzus persicae ) infesting pak choi ( Brassica rapa var. chinensis ) and identified its phytochemical components. Six treatments were evaluated using a Completely Randomized Design, consisting of four WSLE concentrations (25%, 50%, 75%, and 100%), a synthetic insecticide (Bushwhack), and a water control. A 7-day assessment period was conducted to evaluate the aphid mortality rate and lethal concentration of the plant extract. The results revealed that at 100% concentration, it obtained a higher mortality rate comparable to the RRIF (synthetic insecticide), followed by 75% WSLE. The calculated LC 50 of 51.43% classified the extract within the moderate toxicity range. Phytochemical analysis confirmed the presence of bioactive constituents such as alkaloids, flavonoids, saponins, phenols, tannins, steroids, and terpenoids, responsible for insecticidal and antifeedant activities. The use of WSLE demonstrated a cost-effective, biodegradable, and reliable substitute for the control of green peach aphids that promotes sustainable vegetable production.