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Opuntia (Prickly Pear)

We often refer to alien plant species in the various communications from the Reserve. I thought it may be worthwhile looking at the true definition of these alien species and the immediate impact to the Ingwelala properties.

The definition of alien plants “Invasive alien vegetation refers to plants brought to South Africa from other countries, both intentionally and unintentionally, that cause either human, economic, or environmental damage”.

The economic and human damage referred to is applicable more to agricultural practices in the form of damage to crops and livestock.

Without natural enemies, these alien plants take up valuable space, reproduce and spread quickly, replacing the indigenous vegetation, and putting enormous pressure on underground water resources. To date there are over 370 listed species present in the greater Kruger alone, three of which are considered high impact and top the list of needing immediate eradication. Of these, one is prevalent in our immediate surrounds, the Sour Prickly Pear (Opuntia Stricta).

It is unclear when and how this invasive species first originated in South Africa. The most common theories suggest it was brought in from its native Central America as either ornamental plants or for a type of hedging for household privacy.

In our local surrounds, the fruit of the Prickly Pear is eaten by animals (Baboons and kudus mostly) and birds. The seeds scarify as they pass through the animal’s digestive tract. Germination of this seed will then take place in approximately four days which makes it extremely difficult to control. It is of interest that the infestation or individual stands of plants are often found along the historical exit routes of baboons from the Camp area into their daily foraging areas, more specifically the Nhlaralumi River ridge between Argyle Boma and the Camp area, both sides of Bird Hide Road west towards Bird Hide and the Umbabat road area both east and west of the Sekgobela River.

The competition for its survival with the surrounding indigenous vegetation can be obvious when viewing the plant, often found standing alone in the dry winter soils. If left untreated it will progressively kill off any other vegetation in the immediate area.

The preferred and most efficient method of control is a folio spray of MSMA over the entire plant which tends to kill it off completely in approximately 7-10 days.

Our thanks go out for all the reports of plants that require treatment. It certainly makes a huge difference to our efforts to eradicate this problem species.

 

Text by Chris Mayes.