Description
Taken from Missouri Weed ID: http://weedid.missouri.edu/weedinfo.cfm?weed_id=88
Smooth Crabgrass:
| Weed Description: Summer annual, having a prostrate or ascending growth habit, with leaves and sheaths that do not have hairs and stems that do not root at the nodes. Found throughout the United States. |
| Seedlings: Sheaths and blades not hairy, few hairs at mouth only, with a jagged membranous ligule. Seedlings are upright, leaves are rolled in the bud, and the first leaf blade is lanceolate to linear. |
| Leaves: Blades 5-14 cm long, 2-7 mm wide, without hairs. Sheaths are without hairs and closed, with hairs in the collar region only. Ligules are 1-2 mm long, membranous with even margins. Leaves and sheaths may turn dark red or maroon with age. |
| Stems: Prostrate or lying on the ground with tips ascending (decumbent) up to 60 cm long, branching at lower nodes but not rooting. |
| Flowers: Seedhead composed of 2-6 branches (spikes) at the top of stems, each 10 cm long. Spikelets 1.8-2.1 mm long, 0.8-0.9 mm wide, in two rows along the spike, with short mushroom-like hairs. |
| Roots: Fibrous root system. |
| Identifying Characteristics: Sheath and leaves without hairs, mushroom-like hairs on spikelet. May be distinguished fromLarge Crabgrass (Digitaria sanguinalis) by the absence of hairs on the leaves and sheath, and only a few hairs found in the collar region. Additionally, smooth crabgrass does not root at the nodes like large crabgrass. |
Large Crabgrass:
| Weed Description: Shiny, yellowish-brown, 2-3 mm long. |
| Seedlings: Sheaths and blades usually densely hairy, with a jagged membranous ligule. Hairs on the blade and sheath are at a 90 degree angle to the plant surface. Seedlings are upright, leaves are rolled in the bud, and the first leaf blade is lanceolate to linear. |
| Leaves: Blades 1 1/4 to 8 inches long, 3-10 mm wide, with hairs on both surfaces. Sheaths hairy and closed. Ligules are 1-2 mm long, membranous and appearing as if cut off straight across the end, with uneven teeth or margin. Leaves and sheaths may turn dark red or maroon with age. |
| Stems: Prostrate, spreading, branched, and rooting at the nodes. |
| Flowers: Seed head composed of 4-6 branches (spikes) at the top of stems, each approximately 1 1/2 to 7 inches long. Spikelets are elliptic and in two rows along the spike. |
| Roots: Fibrous root system. |
| Identifying Characteristics: Densely hairy leaf and sheath and relatively large membranous ligule. Similar in appearance toSmooth Crabgrass (Digitaria ishaemum), but smooth crabgrass does not have hairs on leaves and sheaths, only a few hairs may be found in the collar region. Additionally, large crabgrass roots at the stem nodes while smooth crabgrass does not. |
Pest image (all)
Scientific name
Digitaria spp.
Pest photo source
Dr. Dallas Peterson, Agronomy, KSU
Weed type
grass
Production period
Preharvest
Weed life cycle
summer annual