In 1963, in her influential book “Silent Spring”, Rachel Carson warned the world of the environmental and human health dangers of pesticide use. Carson promoted the use of biological control as an alternative method for suppressing insect outbreaks and weed infestations. Despite this warning the global expenditure on pesticides has increased annually reaching some USD 50 billion for 2008. Biological control, or the development of host specific natural enemies, offers the most effective and long-term solution to many invasive alien plant species and insect pests.
The Centre for Biological Control (CBC) focuses the majority of their research on understanding the ecological dynamics of invasive pests, aquatic and terrestrial weeds in particular. A large proportion of this work is the development of biological control methods for these invasive plants, which can then be implemented by Governmental Scientists and Management. As mentioned above, biological control is a particularly appealing solution because it is not toxic, pathogenic or dangerous to humans. It also has the advantage of being self- perpetuating once established and usually does not harm non-target organisms found in the environment.
The Centre for Biologial Control at Rhodes University works primairly in two areas:
Biological control of insect pests
All of the plants that we utilize as crops are also attacked by insect pests. It is estimated that the world loses about 50% of its crops to pests. In an attempt to reduce the amount of pesticides sprayed in the environment, some of the research that is undertaken in Entomology at Rhodes University aims at identifying predatory insects such as wasps and fungi and viruses that kill insect pests. This research focusses mainly in the citrus industry, but we also have projects on pests on cabbage, potato and litchi. In addition to being self-perpetuating, it is not as polluting or disruptive to the environment as chemical pesticides, nor does it leave residues on food, a concern to many people today.
Biological control of invasive alien plants
Invasive plants have been brought into South Africa for a number of reasons, including food sources (e.g. prickly pear; Opuntia ficus – indica and guava; Psidium guajava), as garden plants (Cherry-pie; Lantana camara) and sand stabilizers (e.g. Acacias) OR they have been imported accidentally (often through the pet and aquarium trade) and have spread rapidly throughout our landscapes, veld, rivers, dams, lakes, streams and/or irrigation canals.
Invasive weeds are especially problematic because they often compete with native species, monopolize water resources, clog water ways and cost South Africa millions of Rand each year to control, as they are difficult to get rid of. Water weeds are particularly nasty as they impede recreational and subsistence use of our rivers, lakes and streams, they increase the loss of water from our storage systems and most importantly they do a lot of damage to native ecosystems (including plants and animals and even nutrient dynamics) when in high densities. Every year more and more invasive and problematic species are being identified and Biological Control has become an essential tool for the managemrnt and conservation of our natural resources.
Last Modified: Fri, 09 Feb 2018 07:31:05 SAST