Corresponding author, email: rabinson.adhikary@gmail.com (Robinson Adhikari). Journal of Research in Weed Science Volume 3 Issue 3 (2020), pp 263-269. Journal of Research in Weed Science Journal homepage: www.jrweedsci.com Short Communication Weed density and control efficiency of different weed control methods in transplanted rice in Nepal Robinson Adhikary a, *, Bishnu Bilas Adhikari b , Bishnu Prasad Kandel c a Ministry of Agriculture and Livestock Development, Nepal. b Institute of Agriculture and Animal Science, Tribhuvan University, Nepal. c Department of Plant Breeding, Post Graduate Program, Institute of Agriculture and Animal Science, Tribhuvan University, Kathmandu, Nepal. ARTICLE INFORMATION ABSTRACT Received: 2 September 2019 Revised: 10 November 2019 Accepted: 10 December 2019 Available online: 13 December 2019 DOI: 10.26655/JRWEEDSCI.2020.3.2 This study was performed to evaluate the weed density and weed control efficiency (WCE) on transplanted rice under different treatments at a farmer’s field, Bhanu-11, Rupakot, Nepal during Rainy season of 2017. Ten treatments (one manual weeding at 21 days after transplanting (DAT) (T1); two manual weeding at 21 and 42 DAT (T2); three manual weeding at 21, 42, and 63 DAT (T3); single cono weeding at 21 DAT (T4); double cono weeding at 21 &42 DAT (T5); triple cono weeding at 21, 42, and 63 DAT (T6); butachlor as pre emergence (T7); butachlor with single manual weeding at 21 DAT (T8); butachlor with double manual weeding at 21 & 42 DAT (T9) and weedy check (T10) were laid in randomized complete block designs (RCBD) with three replications. At 30 DAT, the highest weed density was recorded at unweeded check (T10) while it was the lowest at butachlor with double manual weeding (T9). At 60 DAT the effective weed control method on weed density was found to be double manual weeding (T2). At 90 DAT triple cono weeding (T6) was found to be more effective on controlling weed density (30) and was at par double manual weeding (T2), double cono weeding (T5) and butachlor with double manual weeding (T9). WCE was the highest in the plot treated with butachlor with double manual weeding at 21 and 42 DAT (T9) and the lowest in the plot treated with butachlor pre emergence (T7) at 30 DAT. At 90 DAT, WCE in the plot treated with triple weeding (T6) was found the highest (78.63%) and the lowest in the plot treated with butachlor as pre emergence (T7) (26.14%). KEYWORDS Major weed Weed recovery percentage Weed population Introduction Rice is one of the principal staple food crop of Nepal. It fulfills the 50% calories requirement of Nepalese people (Gautam et al. 2019; Adhikari et al. 2019). The area, production and productivity of rice in Nepal during fiscal year 2016/017 was 1552469 ha, 5230327 tons and 3.37 tons ha -1 ,