Management of the maize weevil (Sitophilus oryzae L.) using turmeric (Curcuma longa) essential oil

Among the various insect pests infesting stored maize, the rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae), is one of the most destructive pests, capable of causing 100 % infestation and significant qualitative losses. Essential oils (EOs) from botanicals are considered eco-friendly as they show promise against several stored product pests including S. oryzae without leaving any non-toxic residues in the final product. This study aims to evaluate the potential insecticidal effects of essential oil of turmeric, Curcuma longa against S. oryzae under laboratory conditions. A maximum adult mortality of 90.0 % was recorded in fumigant toxicity tests at 65 μL/96 cm³ after 5 days of exposure. Under contact toxicity conditions, 99.13 % mortality was observed at 70 μL after 5 days. Fumigant and contact toxicity tests revealed an LC50 of 60.39 μL and 65.61 μL, respectively, against adults of S. oryzae. At the same concentration (70 μL),turmeric EO observed complete reduction of oviposition and adult emergence. These findings indicate that turmeric EO possesses strong insecticidal properties and could serve as an effective and environmentally safe alternative to synthetic fumigants for the management of S. oryzae in stored maize grains.