Welcome to Arab Journal of Plant Protection
CURRENT ISSUE

Volume 44, Issue 2, June 2026

eSSN 2412-5407
pISSN 0255-982X

مجلة وقاية النبات العربية

Arab Journal of Plant Protection

A Regional Scientific Journal Published Four Times a Year by the Arab Society for Plant Protection

Under Publication
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Effect of The Aqueous Plant Extracts of Garlic and Onion on Controlling Some Insect Pests of Tomatoes and Improving the Physiological Properties of the Crop Plants

Gheraissa1,2, K. Kherraz3*, B. Benamor4,5, N. Cherrada1,2, G.A. Djilani1,6, C.A. Elkalifa1,2 and K. Deboub1

(1) Department of Biology, Faculty of Life and Natural Sciences, University of El Ouedi, Algeria; (2) Laboratory of Biodiversity and Application of Biotechnology in Agriculture, University of El Ouedi, Algeria; (3) Higher School of Agriculture, El-Kouba, Algeria; (4) Higher School of Saharan Agriculture-El Ouedi, Algeria; (5) Saharan Areas Laboratory for Agricultural Modernization and Advancement, Higher School of Saharan Agriculture-El Oued, Algeria; (6) Laboratory of Biology, Environment, and Health, University of El Ouedi, Algeria

*Email address of the corresponding author: [email protected]

DOI https://doi.org/10.22268/AJPP-001473

Abstract

This study aimed to evaluate the insecticidal activity of aqueous extracts from garlic, Allium sativum L. and onion, Allium cepa L. bulbs against three major tomato, Lycopersicon esculentum Mill. pests: the tomato leaf miner, Tuta absoluta (Meyrick), the tomato fruit worm, Helicoverpa armigera (Denis & Schiffermüller), and the adult cotton aphid, Aphis gossypii Glover, with the goal of identifying natural alternatives to chemical control. A further objective was to assess the effects of these extracts on selected physiological and morphological characteristics of tomato plants to verify their safety as plant-based preparations, in comparison with chemical pesticides used. Three chemical pesticides, each targeting a specific pest species, were applied alongside the plant extracts to tomato plants using two application methods: direct foliar spraying and leaf dipping, with evaluations conducted at 24- and 48-hours post-treatment. Results obtained showed that the plant extracts achieved high mortality rates; in the spraying method, they caused 100% mortality against A. gossypii and T. absoluta, and 70% against H. armigera, while the dipping method was slightly less effective. Chemical pesticides consistently exhibited high efficacy (>91.67%) against all tested pests, particularly T. absoluta. Regarding physiological traits, garlic extract notably increased the contents of chlorophyll a, chlorophyll b, total chlorophyll, and total sugars in both leaves and fruits compared to onion extract, control, and chemical pesticides, whereas the latter showed negative effects on these traits. Both plant extracts also reduced the rate of infected fruits, minimized weight loss and microbial/physiological damage, and improved taste scores. These findings highlighted the dual potential of garlic and onion extracts as natural insecticides that are relatively safe for plants, in addition to their role as organic biofertilizers capable of enhancing tomato yield and quality.

Keywords:

Plant extracts, tomato, tomato pests, biological control, organic fertilizers.