Host-plant variety and not climate determines the establishment and performance of Aceria lantanae (Eriophyidae), a biological control agent of Lantana camara in South Africa

The flower-galling mite Aceria lantanae (Cook) (Trombidiformes: Eriophyidae) was released for the biological control of Lantana camara L. (Verbenaceae) in South Africa in 2007, but has displayed variable and patchy establishment throughout the weed's range. Surveys were undertaken in 2013-2014, both seasonally and during the mite's peak infestation periods, to determine the influence of climatic factors on its performance. Although there were seasonal differences in the percentages of mite-infested inflorescences, these did not differ significantly between altitudinal zones. There were also no significant relationships between the percentages of mite-infested inflorescences and either of annual rainfall, temperature or relative humidity. A field inoculation trial revealed significant differences between 10 common South African L. camara varieties in their susceptibility to A. lantanae. Only three varieties displayed appreciable susceptibility (50-61% of inflorescences infested), whereas six displayed only slight to moderate susceptibility (8-21%) and one displayed a lack of susceptibility (no infestation). These data support the contention that differential varietal susceptibility and not climate is responsible for the variable performance of A. lantanae on L. camara in South Africa. Complementing the current biotype of A. lantanae, originally sourced from Florida (USA), with other biotypes from different L. camara genotypes in Central and South America could increase the mite's impact on the weed.