U.S.-South African Cooperation Seeks to Tame Introduced WeedBy
Kathryn Barry Stelljes
July 29, 1998
A new cooperative project between Agricultural
Research Service and South African scientists aims to control Cape ivy, a
weed rapidly taking over natural areas along the U.S. west coast.
The vine was introduced from South Africa as an ornamental plant before the
turn of the century. But now it has spread into wild areas throughout coastal
California and into Oregon, where there are no natural enemies to curb the
Cape ivy reduces the diversity of native plants and reduces precious habitat
needed by rare and endangered plants and animals.
Chemical weed killer is frequently not a control option because Cape ivy
grows in hard- to-reach areas, near water and in areas that contain sensitive
species. So ARS' Plant
Protection Unit in Albany, Calif. and South Africa's Plant Protection
Research Institute in Pretoria are working to implement a biological control
The Pretoria scientists began searching this spring along the east coast of
South Africa for insects and pathogens that appear to control the ivy naturally.
The researchers believe such biocontrols exist because Cape ivy is uncommon in
its homeland, suggesting that natural enemies keep it in check.
Once potential biological agents are found, ARS will test them for safety on
native U.S. plants. Ultimately, if an effective biocontrol is identified, ARS
will apply for permission to release the insect or pathogen.
ARS has released hundreds of beneficial biological control agents against
dozens of pests. The painstaking process of identifying, testing and importing
a biological control insect takes about 10 years.
Scientific contact: Joe Balciunas, USDA-ARS Plant Protection
Research Unit, Western Regional Research
Center, Albany, CA 94710, (510) 559-5975, fax (510) 559-5777,