Research addresses all the usual aspects of a comprehensive biological control programme, notably (i) the identification, importation and host-specificity testing of additional potential biocontrol agents in quarantine, (ii) the release of suitable agents into the field and the monitoring of their establishment and initial effects, (iii) the evaluation of the long-term impacts of biological control on the population dynamics of the target weed species and (iv) the publication of the research results in the appropriate scientific literature. Balloon vine is a category 1 plant (declared weed) in South Africa, which makes it illegal to grow it anywhere in the country. There is therefore no need to limit research to seed-destroying organisms, and the aim will be to release the most damaging, host-specific organisms that can be found - both insects and pathogens.

Surveys were undertaken in Argentina and Brazil to find potential biological control agents for balloon vine (Cardiospermum grandiflorum).  A number of potential agents have been introduced into quarantine laboratories including a seed-feeding butterfly (Chlorostrymon simaethis), a sap-sucking bug, a phytophagous wasp and, a rust fungus (Puccinia arechavaletae).  Unfortunately further work on the bug had to be abandoned after it was found that it could develop on non-target species and the wasp culture could not be maintained.  Host range testing on the butterfly and fungus is proceeding. 

The team leader is Dr David Simelane, e-mail: simelaned@arc.agric.za.