Parthenium hysterophorus L. – parthenium

Parthenium hysterophorus, an annual herbaceous plant native to the tropical Americas, is now a major crop and pasture weed in Australia as well as many parts of Africa and Asia. It is also a human health hazard, causing severe allergic dermatitis and respiratory problems. A major biological control program against parthenium in Qld started in 1977 with scientists based in Mexico and Brazil, and continued until 2002. Over 144 species of herbivorous insects and several pathogenic fungi were identified, of which nine insect species and two rust fungi were introduced into Qld. Seven species of insects and two rust fungi have established on parthenium and are widespread. Key agents are the stem-galling moth Epiblema strenuana, the leaf-feeding beetle Zygogramma bicolorata, the stem- and root-feeding weevil Listronotus setosipennis, the seed-feeding weevil Smicronyx lutulentus and the summer rust Puccinia xanthii var. parthenii-hysterophorae. The combined impact of these agents has resulted in significant reductions in the abundance and impact of parthenium in most situations and seasons, though serious infestations can still occur. Some of these agents have been successfully introduced into India, Sri Lanka and China, and are being considered for use in eastern and southern Africa.