Melaleuca alternifolia essential oil as an environmentally sustainable alternative for controlling Tuta absoluta in tomato

Abstract

Tomato production is highly affected by the tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), a major pest whose management relies heavily on repeated applications of synthetic insecticides, contributing to environmental contamination, resistance development, and risks to non-target organisms. In this context, environmentally sustainable alternatives are urgently needed to reduce chemical dependence in crop protection systems. This study evaluated the insecticidal and antifeedant potential of Melaleuca alternifolia essential oil as a botanical alternative for controlling T. absoluta. The essential oil was extracted by hydrodistillation and chemically characterized by gas chromatography–mass spectrometry (GC-MS). Tomato seedlings were treated with different oil concentrations (0, 2.5, 5.0, 7.5, and 10 mg mL⁻¹), and second-instar larvae of T. absoluta were exposed under controlled laboratory conditions. Larval mortality and foliar consumption were evaluated after 72 h, while acetylcholinesterase (AChE) inhibition assays were performed to investigate the oil’s biochemical mode of action. The essential oil significantly reduced foliar consumption in a dose-dependent manner, achieving a reduction of up to 53.57% at the highest concentration tested. Larval mortality progressively increased with increasing concentrations, reaching 75% at 10 mg mL⁻¹, with an estimated LD₅₀ of 6.62 mg mL⁻¹. Furthermore, the oil demonstrated inhibitory activity against AChE, suggesting neurotoxic effects associated with insect mortality and feeding deterrence. These findings highlight the potential of M. alternifolia essential oil as an environmentally sustainable and biodegradable botanical insecticide for integrated pest management, contributing to reduced reliance on synthetic pesticides and promoting more sustainable tomato production systems.