The response of Parthenium hysterophorus and of its biological control agent Epiblema strenuana under a changing climate
Studies were conducted to evaluate the possible consequences of climate change on Parthenium hysterophorus (Asteraceae, EPPO Alert List) and on the efficacy of its biological control agent Epiblema strenuana (Lepidoptera: Tortricidae). P. hysterophorus was grown under an elevated CO2 concentration. Under such conditions, the plant produced significantly greater biomass, grew taller, produced more branches, produced 37% more seeds per plant and photosynthesized at a greater rate when compared with plants grown at an ambient CO2 concentration. The better water use efficiency of P. hysterophorus under an elevated CO2 concentration suggests that the plant has a greater ability to withstand prolonged periods of drought in the future.
E. strenuana has been used successfully as a biological control agent against P. hysterophorus in Australia and China. E. strenuana significantly reduced the height, biomass and seed production of P. hysterophorus when grown under both the ambient and the elevated CO2 concentration. However, under an elevated CO2 concentration, P. hysterophorus produced more seeds even in the presence of E. strenuana.
Shabbir A, Dhileepan K, Adkins SW (2014) The response of an invasive weed and its biological control agent under a changing climate of CO2 enrichment: management challenges for the future. Abstract of the 4th International Symposium on Environmental Weeds and Invasive Plants, Montpellier (FR), 2014-06-19/23.