Author:
Klötzli Julie,Suter Matthias,Schaffner Urs,Müller-Schärer Heinz,Lüscher Andreas
Abstract
AbstractOutcomes of weed biological control projects are highly variable, but a mechanistic understanding of how top-down and bottom-up factors influence the success of weed biological control is often lacking. We grew Rumex obtusifolius, the most prominent native weed in European grasslands, in the presence and absence of competition from the grass Lolium perenne and subjected it to herbivory through targeted inoculation with root-boring Pyropteron spp. To explore whether the interactive effects of competition and inundative biological control were size-dependent, R. obtusifolius was planted covering a large range of plant sizes found in managed grasslands. Overall, competition from the grass sward reduced aboveground biomass and final root mass of R. obtusifolius about 62- and 7.5-fold, respectively, and increased root decay of R. obtusifolius from 14 to 58%. Herbivory alone increased only root decay. However, grass competition significantly enhanced infestation by Pyropteron spp. and, as a consequence, enhanced the impact of herbivory on aboveground biomass and final root mass. The synergistic effect was so strong that R. obtusifolius plants grown from initially smaller roots did no longer develop. Inoculating R. obtusifolius with Pyropteron species in grasslands should be further pursued as a promising inundative biological control strategy in the weed’s native range.
Funder
European Union’s Horizon 2020 programme
Publisher
Springer Science and Business Media LLC
Reference63 articles.
1. Agrawal, A. A. Resistance and susceptibility of milkweed: Competition, root herbivory, and plant genetic variation. Ecology 85, 2118–2133 (2004).
2. Cheng, F. & Cheng, Z. Research progress on the use of plant allelopathy in agriculture and the physiological and ecological mechanisms of allelopathy. Front. Plant Sci. 6, 1020 (2015).
3. Ferrero-Serrano, Á., Collier, T. R., Hild, A. L., Mealor, B. A. & Smith, T. Combined impacts of native grass competition and introduced weevil herbivory on Canada thistle (Cirsium arvense). Rangel. Ecol. Manag. 61, 529–534 (2008).
4. Sheppard, A., Smyth, M. & Swirepik, A. The impact of a root-crown weevil and pasture competition on the winter annual Echium plantagineum. J. Appl. Ecol. 38, 291–300 (2001).
5. Sheppard, A. W. The interaction between natural enemies and interspecific plant competition in the control of invasive pasture weeds. In Proceedings of the IX International Symposium on Biological Control of Weeds (eds Moran, V. C. & Hoffmann, J. H.) 1–26 (University of Cape Town, 1996).