Evaluation of Botanical Powders for the Management of Rice Weevil (Sitophilus oryzae L. Coleoptera: Curculionidae) in Rupandehi, Nepal

An experiment to manage rice weevil (Sitophilus oryzae L. Coleoptera: Curculionidae) in wheat (Triticum aestivum L. Gramineae) was carried out at Institute of Agriculture and Animal Science (IAAS), Paklihawa Campus, Rupandehi, Nepal. The experiment was conducted under completely randomized design (CRD) with seven treatments viz. neem leaf dust (Azadirachta indica A. Juss) 15 g/kg, tobacco leaf dust (Nicotiana tabacum L.) 10 g/kg, ginger rhizome powder (Zingiber officinale Roscoe) 20 g/kg, garlic cloves powder (Allium sativum L.) 20 g/kg, Sichuan pepper seed powder (Zanthoxylum armatum Roxb.) 10 g/kg, sweet flag rhizome dust (Acorus calamus L.) 5 g/kg, and control with three replication. Result revealed that the highest mortality of weevils was observed in the wheat seed treated with A. calamus (98.33%), followed by N. tabacum (85.67%), A. sativum (73.34%), A. indica (70.67%), Z. armatum (70.34%), and Z. officinale (58.34%). Similarly, the lowest percent weight loss (3.32%) and damage of seed (4.0%) were observed in wheat treated with A. calamus. Moreover, the highest germination (89%) was observed in seeds treated with A. calamus rhizome powder when tested at 90 days after treatment application. Based on weevil mortality and the germination test, it is found that sweet flag rhizome powder is the best treatment against rice weevil followed by tobacco leaf dust and garlic clove powder. Therefore, these botanicals could be one of the effective alternatives for the management of weevil especially to the farmers who do not use chemical insecticides in the rural areas of Nepal.