Eight decades of invasion byChromolaena odorata(Asteraceae) and its biological control in West Africa: the story so far

Weed or not a weed? Density, perceptions and management of Chromolaena odorata (Asteraceae) in West Africa: Voices from Ghana

“…These impacts of C. odorata on crop production are not limited to Ghana, but have also been documented in other parts of West Africa (Aigbedion-Atalor et al, 2019c), where effects are exacerbated by allelopathic properties of the species (Sahid and Sugau, 1993) that lead to increases in its dominance in agroecological systems by displacing agriculturally important crops (Timbilla and Braimah, 1996;Zachariades et al, 2009).…”

“…Overall and with the exception of the Ashanti region, most respondents did not consider C. odorata as a weed, probably because of local awareness of the biological control efforts against it (see Braimah et al, 2013) and thought that it was more beneficial than harmful to human interests. In a recent review, Aigbedion-Atalor et al (2019c) suggested an explanation for this could be the overall countrywide reduction in the density of the plant, mainly due to effects of the introduced biocontrol agents, has reduced its impacts on crop production (Aigbedion-Atalor et al, 2019c). Here, local use of the plant included improvement in soil fertility fallow shrub) and treatment of feverish conditions and bleeding, particularly of farm-related injuries (medicinal shrub), as have been previously documented in Ghana (Timbilla and Braimah, 1996;Braimah et al, 2013).…”

“…Arriving in West Africa in the 1930s, C. odorata rapidly established and has been one of the most researched invasive plant species in West Africa in the past eight decades (Aigbedion‐Atalor et al ., 2019c). It is believed that C. odorata was first recorded in south‐eastern Nigeria in 1937 (Ivens, 1974).…”

“…However, it quickly spread (in less than a decade) countrywide and further into other parts of West Africa with deleterious ecological effects, especially on biodiversity and agriculture (Timbilla and Braimah, 1996). The impacts of C. odorata have been serious, and the species continues to spread into new ranges in West Africa (Aigbedion-Atalor et al, 2019c), as reflected in a recent study showing the first record of the plant in Guinea-Bissau in 2019 (Catarino et al, 2019). Although the impacts of C. odorata on biodiversity, conservation efforts and agriculture in West Africa are clearly articulated, indigenous people have recognised some agricultural and medicinal uses of the plant (Timbilla and Braimah, 1996;Aigbedion-Atalor et al, 2019c).…”

“…The impacts of C. odorata have been serious, and the species continues to spread into new ranges in West Africa (Aigbedion-Atalor et al, 2019c), as reflected in a recent study showing the first record of the plant in Guinea-Bissau in 2019 (Catarino et al, 2019). Although the impacts of C. odorata on biodiversity, conservation efforts and agriculture in West Africa are clearly articulated, indigenous people have recognised some agricultural and medicinal uses of the plant (Timbilla and Braimah, 1996;Aigbedion-Atalor et al, 2019c). It is well documented that people in an area invaded by an alien plant species often find uses for it within a relatively short time (Shackleton et al, 2019), and this is the case of C. odorata in Ghana and across West Africa.…”