Red sesbania (Sesbania punicea) (Fabaceae)
The weed
Red sesbania is a small, deciduous tree of South American origin. It is characterized by pinnate compound leaves, bunches of attractive, bright red to orange flowers and pods with four longitudinal wings. The species used to be a popular ornamental tree, but its heavy seed load and floating pods enabled it to escape into wetlands and river banks across the country. It also invades wastelands, roadsides and ditches in the moister parts of the country. Dense infestations in riverine situations exclude indigenous species, block access to water and hamper water flow, with the result that rivers burst their banks and cause erosion of the water ways.
Control
In terms of the Alien and Invasive Species Regulations (AIS), National Environmental Management: Biodiversity Act (Act No 10 of 2004), red sesbania has been listed as a category 1b species, which necessitates its control or removal and destruction if possible. No trade or planting is allowed. Research during the 1970s and 1980s culminated in the successful establishment of three beetle species as biocontrol agents: the flower bud feeder Trichapion lativentre, the seed feeder Rhyssomatus marginatus and the stem borer Neodiplogrammus quadrivittatus. Together, these beetles are able to practically prevent the addition of any viable seeds to the soil seed bank, and kill virtually all standing trees if they are present in large numbers. Apart from ensuring that all three species of biocontrol agents are present in all infested areas, no need exists for any additional control measures. No more biocontrol research is currently being carried out on this weed.
More information
- The following reviews on research into the biological control of sesbania can be downloaded:
- The following leaflets can be downloaded:
- Sesbania punicea
pdf - Trichapion lativentre pdf
- Rhyssomatus marginatus pdf
- Neodiplogrammus quadrivittatus pdf
Contact: Hildegard Klein, E-mail: KleinH@arc.agric.za.
