Use of essential oil from Mentha arvensis L. to control storage moulds and insects in stored chickpea

BACKGROUND: Fungal contamination and Callosobruchus infestation results in qualitative and quantitative losses of chickpea seeds during storage. Most of the synthetic chemicals used as preservatives have adverse effects. Therefore, the antifungal and insecticidal potential of Mentha arvensis essential oil was evaluated to determine whether this could be an eco-friendly substitute of synthetic preservatives. RESULTS: The stored chickpea seeds were dominated by Aspergillus flavus (46.1%) and 30% isolates among them were found toxigenic. The MIC of Mentha oil against A. flavus was recorded at 400 mu L L-1 and it exhibited broad fungitoxic activity against 14 storage fungi. The oil was found superior to some prevalent synthetic fungicides. Mentha oil showed potent insecticidal activity against Callosobruchus chinensis at different concentrations and exposure times. The oviposition by C. chinensis was completely checked at 10 mu L L-1 while F-1 emergence was completely inhibited at 200 mu L L-1. During in situ experiments, 94.05% protection of the chickpea from C. chinensis by Mentha oil showed superiority over the organophosphate insecticide malathion, where 90.75% protection was recorded. CONCLUSION: The Mentha EO showing potent fungitoxic and insecticidal efficacy and may be recommended as a plant-based preservative in the management of fungal and insect infestation of chickpea and other pulses during storage. (C) 2009 Society of Chemical Industry