Sida acuta Burm.f & spinyhead sida

Sida acuta, Sida rhombifolia and Sida cordifolia are invasive weeds in northern Australian rangelands. Surveys for biocontrol agents of S. acuta and S. rhombifolia were conducted in Mexico from 1984. Sixty-two species of phytophagous arthropods were found and 12 were considered to have potential as biocontrol agents. Six were imported into Australian quarantine and three were approved for release in Australia. The first agent Calligrapha pantherina was released in 1989 and was widely established by 1997. This beetle defoliates S. acuta plants and reduces seed production. After several years of defoliation, populations of S. acuta were replaced by desirable native and exotic pasture species. C. pantherina has its greatest impact on S. acuta in coastal and subcoastal areas. The fate of the other two agents released, two species of Eutinobothrus, has not been investigated, although they are known to have survived the first dry season.