Author
Iain Paterson
i.paterson@ru.ac.za
Rhodes University
Makhanda
Coauthors
Andrew McConnachie, Department of Primary Industry, Orange, Australia
Corin Pratt, CABI, Egham, UK
Patrick Moran, USDA, San Francisco, USA
Guy Sutton, Rhodes University, Makhanda, South Africa
Karla Jaskche, Rhodes University, Makhanda, South Africa
Clarke Van Steendered, Rhodes University, Makhanda, South Africa
Samuel Motitsoe, Wits University, Johannesburg, South Africa
Julie Coetzee, South African Institute for Aquatic Biodiversity/Rhodes University, Makhanda, South Africa
Martin Hill, Rhodes University, Makhanda, South Africa
Abstract
South Africa is globally one of the most active countries in weed biocontrol research and implementation. This includes a long history of targeting invasive alien plants that are problematic in South Africa, as well as indigenous species that are problematic elsewhere. Traditional no-choice testing remains fundamental to pre-release studies, but a greater focus on field host range testing in the native range has characterized recent pre-release studies, particularly programmes against African grasses and Aizoaceae. The diversity of close relatives of the target weed, which are important test plant species, is highest in the native range, and all the potential agents are present, allowing for assessments of multiple species of biocontrol agents, and even multiple target plants, in a single field study. Post-release evaluations in South Africa have been conducted at different levels, from the response of the weed’s physiology to agent damage, to weed population dynamics, landscape impacts, and quantifying socio-economic and ecological returns. Post-release evaluations have generally focused on the lower levels, while neglecting higher ones, but there are some notable exceptions. A key to success has been investment in mass-rearing and, in particular, supporting community-based mass-rearing initiatives. Collaborations with experts from diverse fields outside of the comfort-zone of most biocontrol scientists are required to fully understand the benefits of biocontrol to society.
keywords
field host range
exploratory surveys
African grasses
Ice-plants
quantifying benefits
Highlights
Field host range assessments in the indigenous distribution improve pre-release studies
More post release evaluations at the socio-economic and ecological level are needed
Collaboration with experts from diverse fields will better quantify the benefits of biocontrol