Amaranthus palmeri | Palmer amaranth

Palmer amaranth originate from the Southwestern USA and Northern Mexico but has since spread and naturalised in countries across the world. Palmer is a dioecious species, meaning male and female flowers are borne on separate plants. As a summer annual it is characterized by aggressive growth (up to 5 cm a day) with plants producing over a million seeds. Seeds are small with the majority surviving in the soil for three to six years. Climate change predictions also show that current and future climatic conditions in South Africa are ideal for the establishment and spread of Palmer amaranth. Dispersal of amaranthus seeds are facilitated by strong winds, birds, irrigation water and most importantly the movement of agricultural machinery.

Palmer amaranth was first recorded in South Africa in 2018 in the Northen Cape, since then it has also been recorded in Limpopo, the North West Province, and Kwa-Zulu Natal. 

Herbicide resistance in Palmer amaranth have been reported all over the world with populations in the US in cotton and soybean containing resistance to five herbicide groups (2/B, 14/E, 9/G, 3/K1 and 15/K3). In South Africa we have confirmed resistance towards Group 2/B (ALS inhibitors), Group 9 (G) (EPSPS inhibitor / glyphosate) and Group 14/E (PPO inhibitors).

Suspected cases of Palmer amaanth can be reported to SAHRI for positive identification

Identification

To help identify Palmer amaranth download or Palmer Identification guide in English or Afrikaans at the bottom of the page

Eradication and management 

Below you can also download a Eradication plan as well as a managament plan (in English and Afrikaans) developed in association with HRAC-SA and Croplife.