About Echinochloa crus-galli subsp. utilis (Ohwi & Yabuno) T.Koyama
Echinochloa crus-galli is a species of wild grass that originated in tropical Asia, and was formerly classified as a type of panicum grass. It has a wide range of common names, including cockspur, cockspur grass, barnyard millet, water grass, common barnyard grass, and simply barnyard grass; note that the name barnyard grass can also refer to any other species in the genus Echinochloa. This plant can reach a maximum height of 1.5 meters (4 feet 11 inches). It produces long, flat leaves that are often purplish at the base. Most of its stems grow upright, though some spread outward across the ground, and all stems are flattened at the base. Its seed heads are a distinctive feature, often purplish, with large millet-like seeds held in crowded spikelets. Echinochloa crus-galli is considered one of the world’s worst weeds. It reduces crop yields, and can cause forage crop failures by removing up to 80% of available soil nitrogen. It acts as a host for multiple mosaic virus diseases, and heavy infestations can interfere with mechanical harvesting. A single individual plant can produce up to 40,000 seeds per year. The seeds are dispersed by water, birds, insects, farm machinery, and animal feet, but contamination of crop seed is likely the most common method of spread. Barnyard grass grows commonly in Europe, tropical Asia, and Africa, where it occurs in fields, along roadsides, ditches, and railway lines, and in disturbed areas including gravel pits and dumps. It also invades riverbanks, and the shores of lakes and ponds, and is found in all agricultural regions. This species is invasive in North America; it occurs across the entire continental United States, and is also found in southern Canada, ranging from British Columbia east to Newfoundland. It was first recorded in the Great Lakes region in 1843. It grows across life zones ranging from boreal moist and wet forests, to tropical and very dry to moist forests. It is adapted to nearly all types of wet locations, and is a very common weed in paddy fields, roadsides, cultivated areas, and fallow fields. It grows on a variety of wet sites including ditches, low areas of fertile croplands, and wet wastelands, and often grows directly in water. While it can grow successfully in cool regions, it is better adapted to areas with an average annual temperature between 14–16 °C (57–61 °F). It is not limited by soil pH.
