Barnyardgrass

Barnyardgrass

Weed Flora of Mississippi

Prepared by

Taghi Bararpour and Jason Bond

Family: Poaceae (Grass family)

Genus: Echinochloa Species: crus-galli

History: Barnyardgrass (billion-dollar grass, watergrass, panic-grass, summer grass), originally from Europe and India, now ranges from latitude 50 N to 40 S, in both temperate and tropical habitats. It is a serious weed problem in 42 countries . It is the world’s principal weed of rice and likely has been for a long time. Barnyardgrass is recognizable in Chinese drawings from 1590. No one apparently documented the migration of barnyardgrass into the United States; therefore, this may indicate that there was no interest in the plant as a weed or as possible forage until later.

Life Cycle: Summer annual

Special Characteristics: The success of barnyardgrass is attributed to prolific seed production, seed dormancy, ability to grow rapidly and flower in a range of photoperiods, and resistance to multiple herbicide modes of action. The species is one of the few grass weeds in which ligules are absent. A healthy full-season barnyardgrass plant in California’s Central Valley can produce 750,000 to 1,000,000 seeds, and as many as 2.25 x 10⁶ seeds under optimal conditions. Barnyardgrass is primarily self-pollinated.

Roots: Fibrous.

Ligule: Absent.

Auricles: Absent.

Stems: Usually erect, thick, without hairs (glabrous), often branched at the lower nodes.

Leaves: Rolled in the shoot, smooth, and the leaf sheaths are often maroon at the base.

Flower: Seedhead a terminal panicle. Panicles may be green to purple in color and are comprised of individual spikelets that may develop a 2- to 10-mm long terminal awn.

Seeds / Fruit: The seeds are nearly oval, shiny, and yellowish gray to brown.

Seedling: Seeds are without hairs (glabrous).

Interference: Barnyardgrass competition with dry-seeded rice reduced grain yields from 8 to 79% when competition began at crop emergence and lasted for periods ranging from 15 days to maturity.