Sunil Sigdel^1*, Astha Dhakal², and Sandeep Lamichhane³*

¹Faculty of Agriculture, Agriculture and Forestry University, Rampur, Chitwan, Nepal
²Ratnanagar-15, Chitwan, Nepal
³MSc in Aquaculture, Agriculture and Forestry University, Rampur, Chitwan, Nepal; Former Fisheries Development Officer, Gandaki Province, Nepal

*Corresponding Author: Sunil Sigdel, Faculty of Agriculture, Agriculture and Forestry University, Rampur, Chitwan, Nepal.

Received: July 20, 2026; Published: August 14, 2026

Abstract

Maize weevil, Sitophilus zeamais Motschulsky, is a destructive storage pest that reduces the quantity, quality, and seed value of stored maize in tropical and subtropical regions. Botanical materials offer a locally available alternative to synthetic storage insec- ticides, particularly for smallholder storage systems. A laboratory experiment was conducted in Liwang, Rolpa, Nepal, from April to June 2021 to evaluate the efficacy of sweet flag (Bojho; Acorus calamus L.) rhizome powder against maize weevil in stored maize grain. The experiment was arranged in a completely randomized design with five treatments and five replications. Five doses of A. calamus rhizome powder (2, 4, 6, 8, and 10 g per 600 g of maize grain) were tested. Mortality, grain damage, weight loss, exit holes, and weevil population were recorded and analyzed using analysis of variance; treatment means were separated using Duncan’s mul- tiple range test at the 5% probability level. A. calamus significantly affected all measured parameters. At 70 days after treatment, the 8 and 10 g treatments produced complete mortality, whereas mortality in the 2 g treatment was 43.04%. The lowest grain damage (0.18%), weight loss (0.01%), and number of exit holes (3.40) were recorded at 10 g per 600 g maize, while no live weevils were recorded in either the 8 or 10 g treatment at 70 days. These findings demonstrate strong relative dose performance under the tested room storage conditions. Because untreated and chemical standard controls were not included, the study does not establish absolute efficacy relative to no treatment or conventional control methods. Further controlled validation in farmer storage structures, across maize varieties, and at different grain moisture levels is recommended.

Keywords: Acorus calamus; Bojho; Botanical Insecticide; Maize Storage; Maize Weevil; Sitophilus zeamais

References

1. Ministry of Agriculture and Livestock Development, Government of Nepal. Statistical Information on Nepalese Agriculture 2079/80 (2022/23). Kathmandu, Nepal; (2024).
2. Ojo JA and Omoloye AA. “Development and life history of Sitophilus zeamais (Coleoptera: Curculionidae) on cereal crops”. Advances in Agriculture 2016 (2016): 7836379.
3. Nayak MK., et al. “Resistance to the fumigant phosphine and its management in insect pests of stored products: a global perspective”. Annual Review of Entomology 65 (2020): 333-350.
4. Lal M., et al. “Botanicals to cope with stored-grain insect pests: a review”. International Journal of Current Microbiology and Applied Sciences6 (2017): 1583-1594.
5. Mallah M., et al. “Efficacy evaluation of common botanicals to manage maize weevil (Sitophilus zeamais) under laboratory conditions”. Farming and Management 3.2 (2018): 142-145.
6. Rimal R., et al. “Evaluation of different concentrations of Bojho (Acorus calamus) against maize weevil Sitophilus zeamais (Motschulsky, 1955) and wheat weevil Sitophilus granarius (Linnaeus, 1758)”. Journal of Entomology and Zoology Studies3 (2020): 1358-1362.
7. Aryal S., et al. “Insecticidal toxicity of essential oil of Nepalese Acorus calamus (Acorales: Acoraceae) against Sitophilus zeamais (Coleoptera: Curculionidae)”. Heliyon11 (2023): e22130.
8. Neupane BP., et al. “Evaluation of locally available botanicals for the management of maize weevil (Sitophilus zeamais) in room storage condition”. Psyche: A Journal of Entomology 2022 (2022): 3362779.
9. Raina VK., et al. “Essential oil composition of Acorus calamus from the lower region of the Himalayas”. Flavour and Fragrance Journal 18.1 (2003): 18-20.

Citation

Citation: Sunil Sigdel. et al. “Efficacy of Sweet Flag (Acorus calamus L.) Rhizome Powder Against Maize Weevil (Sitophilus zeamais Motschulsky) in Stored Maize Under Laboratory Conditions in Rolpa, Nepal". Acta Scientific Agriculture 10.6 (2026): 24-31.

Copyright

Copyright: © 2026 Sunil Sigdel. et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.