Populations of Erect Prickly Pear (IMAGE) Pensoft Publishers Caption Populations of erect prickly pear (Opuntia stricta) in the Kruger National Park, South Africa have been effectively reduced to low numbers with biological control (right). Credit Brian W. van Wilgen Usage Restrictions CC-BY 4.0 License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.