Hypericum perforatum L. is a herbaceous perennial plant that was first noticed as an invader in the Southwestern Cape of South Africa in 1945. Following an unsuccessful chemical control programme, a leaf-feeding beetle, Chrysolina quadrigemina Suffrain, was introduced in 1960, which almost completely destroyed dense stands of the weed. In 1972, a gall-midge, Zeuxidiplosis giardi Kieffer, was released and has proved valuable in damaging seedlings in moist habitats. Attempts to establish three other insect herbivore species failed. Hypericum perforatum is now considered to be under satisfactory control in the Southwestern Cape. Although C. quadrigemina, together with Z. giardi, has been pivotal in eliminating the dense stands of H. perforatum, other factors, such as climate, unsuitable habitats and a lack of dispersal agents, have probably also contributed to containing the weed.
Journal articles from the Grassland Society of Southern Africa (GSSA) African Journal of Range and Forage Science as well as related articles and reports from throughout the southern African region.