Reproducing only by seed.
Stems are 5 - 120 cm long, erect, spreading, or lying on the ground and rooting at nodes (a) in contact with the soil.
Has smooth, hairless leaf blades, and upper leaf sheaths usually smooth and hairless, but the lower ones may be somewhat hairy; ligule (g) also membranous but usually a bit longer (2 - 3 mm), and there is a tuft of long hair on either side of the leaf-base (h) of the lower leaves; no auricles.
Inflorescence almost identical to that of Large crab grass (A) but usually with only a single whorl of spikes at the end of the stem (as illustrated in A). Flowers from August to September.
Fibrous root systems.
Both kinds of crab grass are common in southern Ontario but they also occur sporadically in northern and northwestern Ontario. Both occur in row crops and other fields, waste places, gardens and lawns.
Corn yield loss (%)*: 1 % at 1 plant/m2 3 % at 5 plant/m2 Soybean yield loss (%)*: 1 % at 1 plant/m2 3 % at 5 plant/m2 *assumes that the weed has emerged with the crop and has been left uncontrolled all season.
Before heading out, they are distinguished by their tapered leaf blades, their split sheaths with hairless margins (c), their membranous ligules (d, g) with no auricles, their more or less hairy lower leaf sheaths (b), and their either hairy or smooth blades. After heading out, the slender finger-like spikes are distinctive.
Smooth crabgrass is not known to be toxic.
Smooth crabgrass is not a known allergen.
No information exists at this time.
No information available at this time.
Large crabgrass (DIGSA), Fall panicum (PANDI)
Currently none available for this weed. For the latest research on biological weed control: http://res2.agr.ca/Lethbridge/weedbio/index_e.htm#toc
Currently none available for this weed in corn and soybean. Corn gluten meal will inhibit germination of crabgrass seeds in turf.
No documented cases of herbicide resistance to date. For more information on weed resistance: http://www.plant.uoguelph.ca/resistant-weeds/
Large crab grass: A. Plant. B. Leaf base. C. Side view. D. Back view of a portion of spike with several spikelets. [b]Smooth crab grass: E. Leaf-base of lower leaf.[/b]
Leaf blade: Hairless on both sides.
Leaf sheath: Smooth, leaf sheath margins are also hairless.