The invasive 'Lantana camara L.' hybrid complex (Verbenaceae): a review of research into its identity and biological control in South Africa

Recent progress in the nomenclature and genetics of the hybrid-complex 'lantana' is summarized as it pertains to sourcing the best-adapted natural enemies for its biological control. Reasons are given for viewing the whole array of invasive taxa within Lantana L. sect. Camara Cham. (Verbenaceae) as a syngameon, and for surveying natural enemies of camara-like Lantana entities between Florida and Uruguay. To improve the degree of biological control of lantana, additional agents have been selected, evaluated and found suitable for release in South Africa. The quarantine evaluation and current status of 30 candidate biological control agents obtained from the New World is summarized. Of these, seven were found to be suitable for release, according to given criteria, and two new agents, Aceria lantanae (Cook) (Acari: Eriophyidae) and Ophiomyia camarae Spencer (Diptera: Agromyzidae), are improving control of lantana in humid, frost-free areas. No significant non-target effects have been detected. Information on the distribution and abundance of 17 agents and lantana-associated insects established in South Africa is presented: several are mainly coastal and they are scarce overall. Agent proliferation is constrained by a combination of climatic incompatibility, acquired natural enemies and, probably, the broad spectrum of allelochemicals present in the allopolyploid hybrids within the L. camara complex. In the case of lantana, biological control plays a subsidiary role in support of essential mechanical-plus-chemical control. Cost benefits justify the continued development of additional agents.