The Double-Edged Sword: Local Perspectives on the Spread, Impact, Management, and Uses of the Invasive Chromolaena odorata in Southern Nigeria

In Nigeria, Chromolaena odorata poses significant threats to agriculture by disrupting ecosystem structure and function, thereby altering ecosystem services. However, our understanding of its impact, potential uses, and control measures, particularly from the perspective of local communities who interact directly with the plant, presents opportunities for a balanced approach to sustainable management. The aim of this study was to document the knowledge and perceptions of the introduction and spread of C. odorata, its ethnopharmacological applications, and its effects on crops, livestock, and wildlife, as well as discuss control strategies. Using participatory rural appraisal techniques, we administered semi-structured questionnaires to 150 respondents across six villages in Edo State, Nigeria. The findings reveal that C. odorata is a well-recognized invasive species that has been present for several decades and is commonly referred to by its local name, “Awolowo weed”. Although many respondents were unsure of the reasons behind its introduction, most were familiar with its mode of dispersal. A significant proportion of respondents view the weed as a serious threat to agriculture and a major hindrance to human movement by foot to and from their farmlands where C odorata is dominant. However, many also reported its relative ease of management. Interestingly, 92.7% acknowledged the medicinal value of C. odorata, citing its use in treating fever, wounds, and stomach aches, while 84% reported its ability to enhance soil fertility. Most respondents did not perceive the plant as harmful to livestock or wildlife. Though many believe that the plant has continued to spread, 83.8% oppose its complete eradication. Instead, they highlighted Elephant grass (Pennisetum purpureum Schumach) as a more problematic weed that requires immediate intervention. In summary, exploring the local benefits of C. odorata highlights the importance of leveraging local knowledge and practices to develop a robust, integrated approach for its sustainable long-term management.