Amaranthus graecizans L.

Algeria: Amaranthus graecizans germinates in late spring and throughout the summer; flowering takes place from May to October.
Northern Cameroon: Amaranthus graecizans is present throughout the rainy season, but is more frequent and more abundant at the beginning of the crop cycle. Germination begins after plowing and lasts for 1 to 2 weeks. New germination phases take place after each cultural operation (weeding, hilling). Flowering begins 3 to 5 weeks after emergence and fruiting 2 weeks later. Fruiting and seed dispersal takes place in July in non-weeded plots or from September on regular weeded plots. They dy at the end of the rainy season in October or November. The complete life cycle of A. graecizans lasts 4 to 5 months when it starts at the beginning of the rainy season and is reduced to 2 months when it starts in the middle of the rainy season. This reduction in the length of the cycle at the end of the season is linked to the decrease in the length of the day.
Morocco: Amaranthus graecizans flowers and fruits from May to October.

Amaranthus greacizans is a C4 species.

Algeria: Amaranthus graecizans is a common summer species in vegetable crops, orchards and vineyards throughout the country. It grows on sandy loam to clay soils, rich in nitrogen in sunny places.
Northern Cameroon: Amaranthus graecizans is a ruderal nitrophile species, which grows along roadsides, in wastelands and near villages. It is also a weed of annual crops. It grows mainly in well-structured soils such as non-degraded ferruginous soils or alluvial soils, but is infrequent in very clay soils such as vertisols.
Morocco: Amaranthus graecizans is a nitrophilous species common in irrigated crops, wasteland, wet ruderalized areas and wadi beds.

Local harmfulness

Algeria: Amaranthus graecizans is a major "weed". It is one of the most harmful species of crops because it can colonise practically all ecological environments (very frequent species), and its great adaptation to the agricultural environment gives it a very high potential for invading (very high seed production) plots (very abundant species). Plant with allergenic pollen.
Northern Cameroon: In Northern Cameroon, Amaranthus graecizans is present in 20% of cultivated plots. The frequency of this species and its abundance are higher in the Sudanian region, particularly in plots cultivated for more than 10 years and subject to intensive cultivation practices including tilled plowing and especially heavy mineral manures (200 to 300 kg of wheat). fertilizer per hectare).
Morocco: Amaranthus graecizans is a common weed in irrigated crops.

Local control

Algeria: In greenhouse crops, the practice of solarization, a destocking technique, gives excellent results. About chemical control, Amaranthus graecizans is not sufficiently sensitive to 2,4-D which only gives good results as a pre-emergence treatment and on young seedlings. Active ingredients such as bentazone, diuron, glufosinate ammonium, linuron, oxyfluorfen, metribuzin, paraquat (severely restricted use), pendimethalin, prometryne, propyzamide, trifluralin, etc. easily control adult individuals.

Herbarium pictures ReCOLNAT: https://explore.recolnat.org/search/botanique/simplequery=Amaranthus%2520graecizans