Giant Foxtail

Grass (Poaceae family):

Setaria faberi R.A.W. Herrm.

EPPO code:

SETFA

Other names:

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

Species information

Lifecycle:

Annual.

Propagation:

Reproduces by seed.

Emergence:

Typically, giant foxtail is one of the first annual grass species to emerge in the spring. Usually, though, it emerges after broadleaf weeds, like lambs quarter and pigweed.

Habitat:

Although it can be found throughout the province, it is most commonly found in cultivated fields in southwestern Ontario.

Competitiveness:

Agriculture and Agri-Food Canada research has shown that yellow foxtail densities of 20,000 plants/ac can result in a 10–12% yield loss in corn and soybeans.

Resistance:

A number of populations are resistant to Group 2 (for example, imazethapyr) herbicides in Ontario.

Identification clues

Auricles:

None.

Ligule:

Hairy.

Leaf blade:

The upper surface of giant foxtail’s leaf blade is hairy, while the lower surface is hairless.

Leaf sheath:

The margins of the sheath are hairy.

Stem:

Round.

Seed heads:

Giant foxtail’s seed head is bristly and spiked. Typically, its seed head is twice the length of that of green foxtail.

Roots:

Fibrous.

Often mistaken for

I know it's not Fall panicum because giant foxtail’s leaf blade has a hairy upper surface and a hairy leaf sheath margin. Fall panicum, on the other hand, has neither.

I know it's not Green foxtail because the upper leaf blade surface of giant foxtail is hairy, while green foxtail’s is not.

I know it's not Large crabgrass because giant foxtail has a hairy ligule while that of large crabgrass is membranous.