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

Abstract

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.

Eriophyid Mites in Classical Biological Control of Weeds: Progress and Challenges

“…In particular, among the different populations of St. John's wort present in Australia, two of them did not support the development of A. hyperici populations, while the other four were susceptible, but showed some variations in population growth and impact on the plants [24]. This pattern is similar to what was also observed with A. malherbae on field bindweed, Aceria lantanae (Cook) on lantana (Lantana camara L., Verbenaceae) or A. altamurgensis on medusahead, for which variations in the susceptibility to infestation was experimentally demonstrated by testing different populations of their respective targets [103,[110][111][112]. However, A. altamurgensis performed very poorly on the medusahead plants from the location where it was collected (i.e., Apulia, Italy), whereas it performed much better on plants from Sicily, Italy, and from Idaho and Nevada, USA [110].…”

Post-release evaluation of a combination of biocontrol agents on Crofton weed: testing extrapolation of greenhouse results to field conditions

“…There, the pathogen has led to death of seedlings and major or complete defoliation of stems in the drier months (Page and Lacey 2006), and high levels of galling have reduced plant vigour and killed plants (Dodd 1961). Differences in plant varieties may be responsible for the differential success of agents both internationally, and potentially within South Africa (Mukwevho et al 2017). However, Asteraceae are more difficult targets for biocontrol, yielding a 61% success rate [compared for instance with 100% for Cactaceae (Schwarzländer et al 2018b)].…”

Geographic and genetic variation in susceptibility of Butomus umbellatus to foliar fungal pathogens

“…It is now well known that both host-and agentgenotype effects on biological control success can be substantial and spatially variable (Boughton and Pemberton 2011;Mukwevho et al 2017Mukwevho et al , 2018. For example, biological control agents of Hydrilla verticillata vary in performance between dioecious and monoecious genotypes in the US (i.e., host-genotype effects), genotypes which occur mostly in separate geographic areas (i.e., monoecious hydrilla has a northern US distribution and dioecious hydrilla has a southern distribution).…”