Amaranthus | Pigweed | Misbredie

The genus Amaranthus is distributed throughout the world and can be divided into species with agricultural potential (grain and vegetable amaranths) as well as weedy and invasive amaranths that pose a risk to local biodiversity and food security. Uninformative morphological characteristics often lead to difficulty identifying and distinguishing some species and hybridization between species have also been reported.

In South Africa 17 Amaranthus species have been recorded with Amaranthus deflexus (perennial pigweed | meerjarige misbredie), Amaranthus thunbergii (red pigweed | rooimisbredie), Amaranthus hybridus (common pigweed | gewone misbredie), Amaranthus spinosus (thorny pigweed | doringmisbredie), Amaranthus viridus (slender amaranth | skraal misbredie) and Amaranthus palmeri (Palmer amaranth | Palmer misbredie) the most common weedy and problematic agricultural weeds.

Herbicide resistance towards Group 2/B (ALS inhibitors), Group 9 (G) (EPSPS inhibitor / glyphosate) and Group 14/E (PPO inhibitors) have been recorded in South Africa in Palmer amaranth as well as common pigweed (Amaranthus hybridus).

The following resources are available for the management of amaranthus especially in cases where herbicide resistance is present or expected. Any expected cases of herbicide resistance should be reported to SAHRI

 
For more information on the amaranthus species and their managament click on the content below:
 
 
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. 

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Amaranthus hybridus
Smooth pigweed

Amaranthus hybridus or smooth pigweed originates from various parts of the Americas, but has since spread and naturalised in many countries across the world, where it is considered a weed but also used as a leafy vegetable and even as medicine.

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Amaranthus spinosus
Thorny pigweed

Thorny pigweed is a serious weed in tropical and subtropical regions of the world. Originally from Central America it has spread across the warmer parts of the world. It is a problem weed in agricultural areas (especially cotton and tobacco but less common in maize), pastures and orchards.

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- Author Juan Vorster
Published by Juan Vorster

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