BIOLOGICAL-CONTROL OF TRIFFID WEED, CHROMOLAENA-ODORATA (ASTERACEAE), IN SOUTH-AFRICA

Chromolaena odorata (L. ) King and Robinson, an asteraceous shrub from the neotropical region, has become a major weed of crops, plantations and pastures in many parts of the world. Since its introduction into Southern Africa, in the 1940s, C. odorata has spread extremely rapidly along the eastern coast to become the most problematic of the alien invader plants threatening nature conservation areas in Natal. An arctiid moth, Pareuchaetes pseudoinsulata Rego Barros, was released on C. odorata in Natal at the beginning of 1989, but there have been no signs of establishment, probably because of heavy egg predation by ants. Prospects for the biological control of C. odorata are nevertheless considered to be good because there are still many other insect herbivores and fungal pathogens that can be tried.