Biology and laboratory culturing of the root-feeding flea beetle, Longitarsus columbicus columbicus Harold, 1876 (Chrysomelidae: Alticinae): a potential natural enemy of Lantana camara L. (Verbenaceae) in South Africa

Resumen

The introduced ornamental plant, Lantana camara L. (Verbenaceae), is one of South Africa s worst invasive weeds. It has been the target of a biological control programme here for the past four decades. Although several natural enemies have been established, the level of control is considered unsatisfactory, and a number of new potential biocontrol agents are being evaluated. The flea beetle Longitarsus columbicus columbicus Harold is considered to be highly destructive, attacking the roots of lantana, a niche largely ignored by biocontrollers in the past. Little is known about this potential natural enemy, and attributes of its life history and mode of feeding are discussed. Adults feed on the leaves and deposit eggs in the leaf litter near the soil surface. The larvae burrow into the soil, where they feed externally on the secondary rootlets. Development takes about 60 days during summer, with the potential of 2-3 generations per annum in the field in South Africa. Rearing techniques are described, notably the use of a modified cage, and the results are compared with the alternative of rearing cultures in petri dishes. Implications for the host-specificity screening of L. columbicus columbicus and other Longitarsus and root-feeding flea beetle species under laboratory conditions are discussed.