Comparative Efficacy of Chemical, Biological and Botanical Insecticides against Major Tomato Pests in Egypt

Abstract

In this study, the efficiencies of two synthetic insecticides (emamectin benzoate and methomyl), two bio-insecticides [spinosad and Bacillus thuringiensis (Bt)], and essential oils (EOs) of thyme and garlic, were assessed against the main tomato pests: the tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelichiidae); the whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae); and the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae). The study was carried out at the Etay-El-Baroud Agricultural Research Station in the Beheira Governorate, Egypt, during the 2023-2024 growing season. Pest population was monitored 1, 3, 5 and 7 days after treatments applied at the commercially prescribed dosages. When compared to the untreated control, all treatments significantly decreased the number of pests, with the effects being most noticeable on the 7^th day after treatment. The most successful treatment during 2023 was methomyl, which reduced pests by 80.96% for T. absoluta, 87.82% for M. persicae, and 92.90% for B. tabaci. Dipel (Bt) and Tracer (spinosad) demonstrated reduction levels which varied from 58.25 to 75.27%, depending on the pest species, while emamectin benzoate (Ematox) came next with reductions of 62.30, 80.40, and 86.24%, respectively. Particularly at 8 ml/L of garlic oil in particular showed remarkable efficacy in reducing the population of the three pests by 72.50, 89.00 and 76.12%, respectively. Additionally, thyme oil showed notable effectiveness, exhibiting reduction level of 67.70, 78.06, and 69.19%, respectively. The findings of 2023 were further validated by the results from 2024, which confirmed that both chemical and natural compounds consistently suppressed important tomato pests under field conditions.

Keywords:

Tomato pests, synthetic pesticides, bio-insecticides, essential oils, integrated pest management.