What are alien invasive species?

The following plant species are specified as invasive alien species in Zimbabwe and it’s everyone’s responsibility to clear any growing plant and report to EMA inspectors, occurrence of any such plants in his/her property.
Aquatic Species (Those found in water bodies)
Common Name Bottanic Name
Water hyacinth        Eichhornia Crassipes
Kariba weed        Salvinia Molesta
Azolla             Pistia Stratiotes
Water lettuce        Azolla Filiculoides
Water fern                                Salvinia Auriculata
Terrestrial Species (Those found on land)
Common Name        Botanic Name
Jointed cactus        Opuntia Aurantiaca
Moonflower cactus        Harrisia martini
Cactus Rosea        Opuntia Fulgida
Wild oats            Avena Fatua
Dodder             Cuscuta spp
Cherry pie            Lantana camara

1. Cactus Rosea (Opuntia Fulgida)-The Land Invader
This invasive species is mainly found in Matabeleland South Province with the severely affected districts being Gwanda and Beitbridge. It thrives in the very dry and rocky areas spreading from its source areas of the confluence of Umzingwane and Limpopo rivers.
The plant is spreading to other districts and isolated cases have been identified in Insiza and Bulilima.

Socio-Economic and Ecological Effects of the Plant

The plant is covered with strong thorns that easily injure both humans and animals

It displays magnetic characteristics. Once it prickles into the skin, the pain is unbearable and the thorn is not easily removable. Persons have to undergo surgical operations to remove the thorns.

The plant is commonly found in pasture land exposing livestock to its attacks.
The weed propagates vegetatively and rapidly fast thereby reducing both pasture and arable land.
It has already displaced some people from their homesteads.

Wild animals are trapped by the plant leading to their deaths.

How it Spreads

The weed detaches from the plant with the slightest touches and attaches to humans/animals

Livestock easily spreads the weed to watering points, dip tanks and grazing land as they roam around.

People have been fooled by the attractiveness of the plant’s purplish flowers and have planted it in their homes as an ornamental plant.

Recommended Eradication Methods
The plant can be eradicated using mechanical, chemical and biological methods. In Zimbabwe, only the mechanical method has been used by local farmers in collaboration with development partners.

Cut and bury in situ — the plant is cut and buried in a deep pit without moving it as this may result in further spreading due to detachment. Communities have advanced this method by first burning the thorns followed by stumping and deep burying of the plant

Cutting, crushing, drying and burning — this method has been done successfully in some areas but the method can also pose danger to humans and it is time consuming.

In South Africa they use a chemical called herbicide 2-4-STP to spray the plant but the method is expensive and has not been tried in Zimbabwe.
Biological control — this is the use of a natural predator to eliminate/feed on the plant. The dactylopius species has been used successfully in South Africa. However in Zimbabwe, research is being done by EMA on the pros and cons of this method as there is a need to establish means of eradicating the predator once the weed has been eliminated.

EMA Interventions