Scientists call for urgent research into 'real' impacts of invasi...(prevention and control and the potential...)

CABI is world-renowned for its extensive work in working with countries to help prevent and control invasive species. As well as advising on how to control invasive weeds and pests using a complementary array of pest management approaches, CABI specialises in natural control methods. This focuses on finding and developing natural enemies from the species country of origin and introducing them to the environment where it has invaded. One example is the Rastrococcus mealybug which devastated mangoes in West Africa. CABI introduced a highly specific wasp from Asia, which proved extremely effective in controlling the mealybug. Natural control methods for other weed species such as Mikania micrantha and Water Hyacinth have also been successfully used.

Among GISPs case studies is the Triffid weed (Chromolaena odorata), a plant native to the Americas which has severely impacted natural areas in Africa and reduces crop productivity in agriculture and grazing. In Ghana the study showed that the weed occupies 59% of all arable lands, and in Ubombo, South Africa it reduces the grazing capacity of animals by 150%. Effective control would see an increase in production by 34% and a gain of US$25.6 per hectare for each farmer.

Another example is the Larger Grain Borer which has been recorded in over 18 African countries. The Borer is a major pest of staple food in Africa, especially farm-stored maize and cassava. By studying the Borer, GISP reported that its impact is greatest in rural, small-holder farming systems where yield losses range from 23-60%.

Sarah Simons, Global Director of Invasives Species at CABI concludes:

By concentrating on a number of specific problem weeds in Africa, we are able to identify the effects they have on a countrys overall economy and also on the farmers and their families. This sort of information is essential if govern
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