Yellow Foxtail

Grass (Poaceae family):

Setaria pumila (Poir.) Roem. & Schult.

EPPO code:

SETLU

Other names:

Bottle brush, bottle grass, bristle grass, millet, pigeon grass, wild millet

Species information

Lifecycle:

Annual.

Propagation:

Reproduces by seed.

Emergence:

Yellow foxtail typically emerges later than other annual grass species (for example, green foxtail, witchgrass) and around the same time as eastern black nightshade.

Habitat:

It is found mainly in cultivated fields throughout the province.

Competitiveness:

Agriculture and Agri-Food Canada research has shown that yellow foxtail densities of 20,000 plants/ac can result in a 5% yield loss in corn and soybeans.

Resistance:

A number of populations are resistant to Group 5 (for example, atrazine) herbicides in Ontario.

Identification clues

Auricles:

None.

Ligule:

Hairy.

Leaf blade:

The base of yellow foxtail’s leaf blade is covered with a number of straggly hairs that are roughly 1–2 cm in length.

Leaf sheath:

The margins of the sheath are hairless.

Stem:

Young seedling plants appear to have a round stem, but as the plant gets older the stem is distinctively flat. Of the common annual grasses in Ontario, only yellow foxtail and barnyard grass have flat stems.

Seed heads:

Yellow foxtail has a spiked seed head, typically 4–6 cm long, with larger seeds than that of other foxtail species, but shorter bristles.

Roots:

Fibrous.

Often mistaken for

I know it's not Barnyard grass because yellow foxtail has a hairy ligule, but barnyard grass has no ligule at all.

I know it's not Large crabgrass because yellow foxtail has a hairy ligule.

I know it's not Proso millet because yellow foxtail has a flattened and hairless leaf sheath.

I know it's not Witchgrass because yellow foxtail does not have a hairy stem.