Efficacy of plant based essential oils as bio-pesticides against tomato leaf miner (Tuta absoluta) (Lepidoptera: Gelechiidae) in tomato (Solanum lycopersicum) production

Abstract

Tomato (Solanum lycopersicum) is one of the most widely grown vegetable crops in Zimbabwe and contributes significantly to household nutrition and income. However, its production is severely constrained by the tomato leaf miner, Tuta absoluta, a destructive pest capable of causing substantial yield losses. Excessive reliance on synthetic insecticides has led to concerns regarding insecticide resistance, environmental pollution, and risks to human health, creating a need for safer and sustainable alternatives. This study evaluated the efficacy of neem oil (Azadirachta indica) and clove oil (Syzygium aromaticum) used individually and in combination against Tuta absoluta in tomato. The experiment was conducted at Sangere Farm in Bindura, Zimbabwe, using a Randomized Complete Block Design (RCBD) with four treatments, namely the untreated control, clove oil, neem oil, and a combination of neem and clove oils, each replicated five (5) times. Data were collected on plant height, pest population density, leaf damage, and the percentage of undamaged fruits. Analysis of variance (ANOVA) was performed using GenStat and treatment means were separated using the Least Significant Difference (LSD) test at the 5% level of significance. Results showed that the botanical treatments significantly reduced T. absoluta infestation and leaf damage compared with the untreated control. The combined application of neem and clove oils consistently recorded the lowest pest population and leaf damage, while also producing the highest percentage of undamaged fruits. Although neem oil and clove oil applied individually provided moderate control, their combination proved to be more effective, suggesting a possible synergistic effect between the two botanical oils. The findings of this study demonstrate that neem and clove oils, particularly when used together, offer a promising and environmentally friendly alternative for managing T. absoluta in tomato production. Their use could contribute to sustainable pest management and reduce dependence on synthetic pesticides among smallholder tomato farmers in Zimbabwe.