Host range and impact of the stem- and leaf-deforming thrips, Liothrips tractabilis: a biological control agent for Campuloclinium macrocephalum, in South Africa

Abstract

We report on the host range and impact of Liothrips tractabilis Mound and Pereyra (Thysanoptera: Phlaeothripinae), the first biological control agent to be considered for Campuloclinium macrocephalum (Less.) DC. (Asteraceae) (pompom weed) in South Africa. Laboratory host-range tests were conducted on 45 Asteraceae species. Field host range studies included 16 Asteraceae species. Results of both laboratory tests and field host range data indicated that L. tractabilis is suitably host specific to C. macrocephalum and hence safe for release in South Africa. Laboratory impact studies on both seedlings and regrowth showed that, even under low inoculation densities, L. tractabilis had a significant impact on plant height, number of leaves, flower production and biomass. Based on the above data, permission for the release of the thrips was applied for, and in June 2013, granted by South African authorities. First releases of L. tractabilis were made in the summer of 2013/2014, and in November 2014 its establishment was confirmed.