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Parthenium hysterophorus L. (Asteraceae), commonly known as famine weed in South Africa, is one of the most invasive weeds worldwide, accountable for losses to biodiversity, agriculture, the economy, and the health of livestock and human beings. The spread of this weed is not easy to manage or reverse. With globalization, trade, and human movement, it will continue to spread, allowing its range to expand into new areas. This weed has serious adverse effects on rangeland and agricultural crop production. Because of its unique characteristics, its invasiveness and competitive success rates are attributed to its high reproductive ability, fast growth rate, tolerance to environmental stresses, climate change adaptability, allelopathic potential, and unpalatability to animals. Parthenium hysterophorus dominates diverse habitats by spreading quickly as a contaminant of grain and other crop products and through farm machinery. It is widely distributed and has become problematic in various countries, including South Africa. It has successfully invaded several provinces in the country since its introduction in 1880. Since plant invasions are not universal, this study aimed to review research that has been conducted on the aggressive weed P. hysterophorus to understand the ecological characteristics that enable its successful establishment, the economic costs associated with its detrimental impacts, and to briefly assess knowledge gaps to improve its management strategies. [ABSTRACT FROM AUTHOR]

Verbesina encelioides (Cav.) Benth. & Hook. Fil ex Gray (Asteraceae) is a perennial herb species belonging to the family Asteraceae. The plant is an aggressive obligate outbreeder weed that has invaded vast expanses of pastures, orchards, and forest areas in tropical and subtropical regions. The purpose of this study was to determine the suitability of current and potential future habitats for V. encelioides, an invasive weed in South Africa, using species distribution modelling techniques with the sdm package in R. The result of the ensemble model, based on current climatic conditions, highlights that Verbesina encelioides has a high probability of occurrence in all nine provinces of South Africa, across all the projected future scenarios, namely, 2030, 2050, 2070 and 2090. Area values ranged from 810,612.09 km2 in 2070, an increase of 4.23% over the current projection, to 663,356.44 km2 in 2090, a decrease of 14.7% from the current projection. The outcome of these predictions showed that V. encelioides would benefit from the predicted climate change in South Africa. The findings could be used as a warning to implement early detection and a rapid response, or for developing one. [ABSTRACT FROM AUTHOR]