2021, Volume 4, Issue 2 Original Article: Management of weeds in irrigated rice cultivation in the middle valley of the Senegal River Ma Anta MBOW a,b, *, Amy Thiao b , Rahimi Mballo c , Cheikh Ahmed Tidiane Kane d , Mame Samba Mbaye a , Kandioura Noba a a Faculté des Sciences et Techniques, Biologie Végétale, Université Cheikh Anta Diop; BP 5005 Fann-Dakar, Senegal. b CNRF, BP 2312, Dakar, Senegal. c CRA/ISRA, Saint Louis, Senegal. d ENSA/Université de Thiès. Senegal. Use yor device to scan and read the article online Citation Ma Anta MBOW, Amy Thiao, Rahimi Mballo, Cheikh Ahmed Tidiane Kane, Mame Samba Mbaye, Kandioura Noba. 2021. Management of weeds in irrigated rice cultivation in the middle valley of the Senegal River. Journal of Research in Weed Science, 4(2), 177-187. http://dx.doi.org/10.26655/JRWEEDSCI.2021.2.4 Article info Received: 26 October 2020 Accepted: 20 January 2021 Available Online: 15 February 2021 Checked for Plagiarism: Yes Peer reviewers approved by: Dr. Mohammad Mehdizadeh Editor who approved publication: Dr. Amin Baghizadeh *Corresponding Author: Ma Anta MBOW (maanta1810@yahoo.fr) Keywords: Herbicides, Rice cultivation, Sowing methods, Senegal, Weed management. A B S T R A C T In the valley of the Senegal River, weeds represent one of the major constraints of irrigated rice cultivation. In that context, the development of efficient and adapted methods for better management of weeds is critical. This study aims at evaluating the efficacy of the combination of two formulations of herbicides (Eros Gold and Londax) and two sowing methods (direct sowing and transplanting) on rice weeds in a Split Plot design with three replicates. The weed flora was evaluated through phytosociological surveys with three observations: before heading, after heading and ripening stages of rice. Floristic surveys identified 16 families, 25 genera and 28 species of weeds. In addition, the results showed that Eros Gold had a significant effect with sowing methods on the decrease of sedges and grasses density but more specifically on the abundance- dominance of broadleaf weeds (dicotyledons) before and during heading stages of rice. On family groups, Cyperaceae (15.39 ind/ha), grasses (15.72 ind/ha) and dicotyledons (24.94 ind/ha) are more sensitive to Eros Gold in broadcast sowing than in transplanting mode with 26, 56 ind/ha, 26.50ind / ha and 27.94 ind/ha respectively. Introduction ice (Oryza sp.) is a cereal with great importance in the world. It is the second most cultivated cereal, and the third most consumed and exported in the world (FAO, 2013). Senegal is the second-largest importer of rice in West Africa after Nigeria (MAH, 2004). These imports continue to create a disequilibrium in the trade balance of the country with currency outflow of about 100 billion CFA per year (Gueye, 2004). To mitigate these adverse effects on the economy, the State took the option of developing irrigated rice cultivation in the regions of Saint-Louis and Kolda and the consolidation of rainfed rice cultivation in the south (Ndione, 2010). In 2014, Senegal made self-sufficiency in rice a priority through PRACAS (program to accelerate the pace of agriculture in Senegal) (MAER, 2014). However, biotic and abiotic constraints constitute the actual brake of rice production. Among these biotic constraints, weeds constitute a crucial problem, and their control is a fundamental element for the enhancement of production factors (Rodenburg and Johnson, 2009). Uncontrolled evolution of weeds can lead to a total loss of rice production, although such R