In this communication, we report the results of fumigant toxicity assays on the essential oils of 15 African plant species, and the analysis and identification of the active constituents of the oil of Conyza
canadensis (L.) Cronq.: Horseweed; August; field; frequent; USIH 1019.
Characterization of invasive Conyza
species (Asteraceae) in Europe: quantitative trait and isozyme analysis.
The work reported here is the first study, as far as we know, in which factors were manipulated in the field in order to investigate some of the ecological interactions influencing performance of two closely related introduced annuals, Conyza
canadensis (L.) Cronq.
In a similar study, a soybean cultivar with an extremely short growth cycle showed a high productive potential, similar to that of a cultivar with a medium growth cycle; however, in competition with Conyza
bonariensis L., the first cultivar showed a considerably reduced grain yield (Trezzi et al., 2013).
Whereas pattern of concentration of these anti-nutritional/ insect repellant/ biochemical deterrent attributes for remaining six plant species were Carthamus oxicantha > Centaurea iberica > Echinops griffithiamus > Conyza
bonarensis > Acroptilon repens > Achillea welhemsii.
Biology and ecophysiology of hairy fleabane (Conyza
bonariensis) and horseweed (Conyza
Host plant(s): Althea rosea (3, 6, 7, 11, 13, 14); Amaranthus viridis (6, 7); Chenopodum album (6, 7); Bidens biternata (11, 14); Conyza
canadensis (3,11); Coriandrum sativum (11); Dendranthema indicum (3, 6, 7, 11, 14); Euphorbia prostrata (6); Parthenium hysterophorus (1, 2, 3, 6, 7, 8, 11, 13, 15); Solanum nigrum (6, 7, 10) and Sonchus asper (3, 6, 7, 11).
Due to the wide use of the herbicide glyphosate, nowadays there is a large number of plants with total or partial resistance to it, such as: Amaranthus viridis, Bidens pilosa, Commelina benghalensis L., Conyza
bonariensis, Cyperus rotundus, Euphorbia heterophylla L., Ipomoea sp., Senna occidentalis and Spermacoce latifolia (Takano et al., 2013).