In one of the better known success stories of biological control, prickly pear cacti (Opuntia spp.), invasive in Australia, were nearly wiped out by the Cactoblastis moth (Cactoblastis cactorum) in the 1930's. Now comes news that prickly pear may be making a comeback. In Southern Australia, populations of the cacti are starting to spread, but in scattered remote areas, making biocontrol difficult. One scientist suspects that they are dealing with a different species, Opuntia robusta, and that a search for a new biocontrol is necessary.