Echinochloa crus-galli (L.) Beauv.
Description
Introduced from India and Europe, this species has spread throughout Pennsylvania and much of the United States. Barnyardgrass persists in many different soil types and can tolerate wet soils and moderate drought conditions. This species is well adapted to sunny areas but can also survive in partially shaded conditions.
Barnyardgrass reproduces by seed, which is easily disseminated via mowing equipment, shoes, animals, and transfer of soil. Homeowners and professional turf managers typically find its coarse texture and poor mowing characteristics objectionable in stands of cool-season turfgrass. Barnyardgrass is not as common in lawns as other summer annual grasses, such as crabgrass, mostly because it does not tolerate low mowing heights for long periods. This species is relatively easy to identify and can be controlled using good cultural practices and certain herbicides applied at the correct time of year and growth stage.
Life Cycle
Barnyardgrass belongs to the Poaceae family and has a summer annual life cycle. Seed of this species begins to germinate in spring and continues through early summer. Seeds can germinate over a wide range of soil temperatures, with optimum temperatures ranging from 68 to 87 F. Following germination and emergence, barnyardgrass plants make vegetative growth during late spring and summer. Seedheads are produced from July to September and can generate thousands of seeds per plant. Barnyardgrass plants exhibit a reddish-purple color in early fall then turn brown and die following frost events in mid to late fall. Seeds produced in late summer and early fall give rise to new plants the following spring given proper conditions for germination and emergence.
Identification
Leaf blades of barnyardgrass are pale green and coarse, approximately ¼ to ½ inch wide and 2 to 6 inches in length, with a prominent midvein running lengthwise down the center and pointed at tips. Barnyardgrass can be distinguished from other summer annual weed grasses in lawns by the lack of a ligule and auricles in the collar region (located at the junction of the leaf blade and sheath). Stems have a reddish-purple color at the base. Seedheads are panicles, pyramid-shaped, green with a red or purple tinge, and composed of multiple spikelets containing florets with seeds. Seeds are small (1 to 2 millimeters in length), somewhat elliptical, and with pointed tips. Depending on the biotype, florets may or may not have awns at tips. Even on individual plants, some florets may have awns, whereas others do not have awns.
Cultural Control
Barnyardgrass is introduced into turf stands primarily through transfer of seed on maintenance equipment, shoes, and soil used for renovation projects. Although there is no practical way to detect seeds in soil, using soils from sites with no previous history of barnyardgrass infestation can lessen the chances of contamination of turfgrass sites. If only a few barnyardgrass plants are infesting a lawn, they can be removed by hand pulling or by using a trowel. Improving turf density through fertilization, irrigation during drought conditions, and use of turfgrasses well-adapted to site conditions will help reduce infestations of barnyardgrass. If infestations occur in lawns, mowing frequently at cutting heights below 3 inches will help suppress leaf growth and formation of seedheads.
Chemical Control
Barnyardgrass can be controlled with certain preemergence herbicides if applications are made in spring before soil temperatures reach 62 F. Active ingredients that have shown good preemergence control of barnyardgrass include prodiamine (Barricade and other prodiamine-containing products), pendimethalin (Pendulum, Pre-M, and other pendimethalin-containing products), and dithiopyr (Dimension and other dithiopyr-containing products). Selective postemergence herbicides labeled for control of barnyardgrass include products containing fenoxaprop-p-ethyl (Acclaim Extra and Last Call), quinclorac (Drive XLR8), and topramezone (Pylex). Be sure to follow label precautionary statements, restrictions, and directions regarding rates and timing of applications when using these herbicides.
