During their recent field visits in Namutumba District in Uganda, Jonne Rodenburg and Mamadou Cissoko observed again quite some inland valley arable fields infested by Rhamphicarpa fistulosa. They found this species in a maize field and also in an upland rice field on the upper parts of an inland valley (near Ivukula; 0°51’21” N – 33°40’56” E and 0°48’46’ N – 33°39’16”). In this field, the Rhamphicarpa infestation levels were overwhelming. The farmer confirmed that this field is free-draining and he informed us that he encountered the species for the first time in 2013 (last season). Rhamphicarpa is known to be favoured by water-logged and temporary inundated soils and therefore finding this species on a free-draining upland soil is quite a surprise to us. Also the seemingly quick and successful invasion rate is remarkable. The two observations combined (broad ecological niche range and high invasion rate) suggests that Rhamphicarpa is a highly invasive species.
The attached photos show farmers harvesting rice in the highly infested upland field and a close-up of Rhamphicarpa and rice with the farmer on the background.