Biocontrol of a perennial legume, Sesbania punicea, using a florivorous weevil, Trichapion lativentre: weed population dynamics with a scarcity of seeds

Summary

The establishment in South Africa of a florivorous, apionid weevil, Trichapion lativentre, on Sesbania punicea, a leguminous weed of South American origin, has reduced seed production of the plants by >98%. Surveys of the age structure and density of plants in infestations of S. punicea throughout South Africa have shown that the rate of recruitment of seedlings has drastically declined within a few years in many areas, due to the weevils. However, there has unexpectedly not been a corresponding decline in the density of mature plants in extant infestations of S. punicea. In spite of this, T. lativentre has curtailed the rate of spread of the weed into uninvaded habitats and has impeded reinvasion into areas cleared of infestations by mechanical means or by another complimentary biocontrol agent.