Biorational Insecticides as Seed Protectants on Tribolium castaneum (Herbst) in Stored Sesame
B. Keerthana *
Department of Entomology, Professor Jayashankar Telangana State Agricultural University, Rajendranagar, 500030-Telangana, India.
A. Padmasri
Regional agricultural Research Station, Palem, PJTAU, 509315-Telangana, India.
P. Duraimurugan
Division of Crop Protection, ICAR- Indian Institute of Oilseeds Research, Rajendranagar, 500030-Telangana, India.
K.S.V.P Chandrika
Agricultural Chemicals, ICAR- Indian Institute of Oilseeds Research, Rajendranagar, 500030-Telangana India.
Praduman Yadav
Biochemistry, ICAR- Indian Institute of Oilseeds Research, Rajendranagar, 500030-Telangana, India.
*Author to whom correspondence should be addressed.
Abstract
Aim: To evaluate the efficacy of essential oils (EOs) and insect growth regulators (IGRs) against Tribolium castaneum (H.) infesting stored sesame seeds.
Study Design: Completely Randomised Design.
Place and Duration of Study: ICAR-Indian Institute of Oilseeds Research, Division of Crop Protection, Rajendranagar between January to June 2024.
Methodology: The study involved six treatments viz., clove oil (5 ml kg⁻¹), peppermint oil (5 ml kg⁻¹), pyriproxyfen 10 EC (5 ppm kg⁻¹), azadirachtin 1500 ppm (5 ml kg⁻¹), deltamethrin 2.8 EC (1 ppm kg⁻1) and an untreated control. The repellent activity of treatments were studies using area preference method. One hundred grams of treated seeds were infested with ten pairs of freshly emerged Tribolium castaneum adults and incubated at 25°C and 55% RH. Adult mortality was assessed at 1, 3, 5, 7, and 14 days after treatment (DAT) using Abbott’s formula.
Results: Results revealed that all treatments were having strong repellent activity. Among all treatments, peppermint oil @ 5 ml kg⁻¹ recorded the highest per cent repellency (98.00%). The treatments caused significantly higher mortality than the control. Among all treatments, peppermint oil @ 5 ml kg⁻¹ recorded the highest adult mortality at 14 DAT (62.33%), which was on par with the standard chemical (deltamethrin) and botanical (azadirachtin) checks. Clove oil and pyriproxyfen showed moderate efficacy. The insecticidal activity of peppermint oil was attributed to its major bioactive compounds-menthol, menthone, limonene, carvone, and pulegone which disrupt insect nervous, respiratory and hormonal systems.
Conclusion: This study highlights the potential of EOs and IGRs as eco-friendly alternatives to synthetic insecticides in storage pest management. Their multiple modes of action also reduce the risk of resistance development, making them suitable alternatives for sustainable pest control strategies. however, further studies are required to increase their persistence and efficacy under long term storage conditions.
Keywords: Essential oils, insect growth regulators, peppermint oil, sesame, bioactive compounds