Imperata cylindrica (graminée)

Écologie Distribution Gestion Impacts Références et liens Contacts

Étude de cas sur les impacts Benin   Agricole: Imperata cylindrica is a problematic invasive agricultural weed and considered the most problematic of weeds in Benin (Vissoh et al. 2004). Ghana   Agricole: Imperata cylindrica is a problematic invasive agricultural weed in Ghana. The cost of weed control was 20 to 60% higher in I. cylindrica-infested fields ($71/weeding/ha) than in other fields. Eighty- six percent of fields that relied on slash-burn method of land preparation had severe I. cylindrica infestation. Infestations > 50% cover, mean density of 33 plants m-2 and shoot height range of 15–300 cm were observed on 60% of the fields. Farmers perceived average yield losses of 30–80% ha–1 due to speargrass interference, implying a national average crop loss ha-1 of $31–$84, $155–$414 and $272–$727 for maize, cassava and yam systems, respectively. Reductions in food quality due to the piercing nature of the rhizomes was also problematic (Bolfrey-Arku et al, undated). Nigeria   Agricole: Imperata cylindrica caused yield losses of over 70% in both maize and sorghum when the two crops were intercropped and up to 80% yield reduction in cassava (Terry et al. 1996). Florida (USA) (United States (USA))   Menace pour les espèces en danger: Imperata cylindrica is considered a threat to federally-protected species such as the 'Vulnerable (VU)' gopher tortoise (see Gopherus polyphemus) and the 'Vunerable (VU)' Camp Shelby burrowing crayfish (see Fallicambarus gordonii) based on its negative effects on habitat (Yager & Smith 2009). Modification de régime des feux: Imperata cylindrica was found to almost double litter biomass in ainvaded locations of Florida compared to uninvaded plots, which increases potential fuel for fires (Plack & Gottchalk 2001).