An integrated management plan for the control of Opuntia stricta (Cactaceae) in the Kruger National Park, South Africa

Abstract

Opuntia stricta is the most problematic alien plant species in the Kruger National Park (KNP) where 30000 ha around Skukuza have been invaded by the weed. Control of 0. stricta is expensive and time consuming and there are insufficient resources available for the task at present. Biological control using the moth Cactoblastis cactorum has only been partially successful and herbicidal control remains the main method for tackling the problem. In order to optimise the control operation against 0. stricta, a management plan has been developed for the KNP. The infested region of the park has been divided into 18 management units, each of which will be treated in turn. During the first three years the control operations will clear 0. stricta from the peripheral units, to prevent the spread of the weed into other areas of the KNP, after which the central units will be tackled. The objective is to destroy all mature fruiting plants and those nearing maturity to curb long-range (seed) dispersal of the weed. The small juvenile plants, which are difficult to detect, will be suppressed by C. cactorum. After five years the problem should be contained to the extent that an ongoing 'holding' programme will be sufficient to keep the weed in check. The success of the plan will depend on increased resources being committed to alien plant control in the Kruger National Park.