Garlic essential oil nanoemulsion for sustainable management of Bemisia tabaci and phytotoxicity evaluation in four key horticultural crops

Abstract

[EN] Bemisia tabaci is a cosmopolitan pest damaging many crops, leading to significant yield losses through direct feeding activity, honeydew deposition, as well as virus transmission. The overuse of synthetic insecticides has prompted resistant pest populations, necessitating alternative control tools. This study evaluates the insecticidal efficacy of a garlic (Allium sativum) essential oil (EO) nanoemulsion against different life stages of B. tabaci, its effect on adult fertility, and its phytotoxic effects on cucumber, eggplant, tomato, and pepper. The EO was chemically characterized by GC-MS and then used to develop an EO-based nanoemulsion by high-pressure microfluidization. The garlic EO nanoemulsion was highly effective against nymphs and adults, achieving over 80 % and 90 % mortality, respectively, at the highest tested concentrations. Furthermore, treated adults exhibited a marked decrease in oviposition rate. At the highest concentration, oviposition was almost completely inhibited. While ovicidal activity was limited, with less than 50 % egg mortality observed at the maximum concentration, the combined impact on adult mortality and produced offspring highlighted the nanoemulsion's potential to reduce the target pest population. No significant phytotoxicity at LC50 across all tested crops was revealed, while LC90 concentrations caused moderate damage to cucumber and eggplant but were less detrimental to tomato and pepper. On this basis, garlic EO nanoemulsions may be an eco-friendly alternative to conventional insecticides for whitefly control. By targeting multiple life stages and reducing reproductive success, garlic EO nanoemulsions have potential to be used in integrated pest management strategies, although field studies are needed to further evaluate the EO nanoemulsion.