Digitaria

Digitaria is a genus of about 250 species of grasses in the family Poaceae, commonly known as crabgrasses. The name derives from the Latin digĭtārius, meaning “finger,” a reference to the characteristic finger‑like spreading growth habit of many species. Members of the genus are annual or perennial herbs with prostrate or erect stems, and they often form dense mats or low tufts. The inflorescence is a digitate panicle composed of several finger‑like branches bearing spikelets that may be fertile or sterile. Leaves are typically flat, linear, and some species possess a distinctive rough or hairy texture.

Crabgrasses are native to tropical and subtropical regions worldwide, with species occurring in the Americas, Africa, Asia, and Oceania. Several species have become naturalized in temperate zones, where they are regarded as weeds in lawns, gardens, and agricultural fields because of their rapid emergence from seed and ability to thrive under low‑cut, high‑traffic conditions. The most widespread weed species, Digitaria sanguinalis (large crabgrass) and Digitaria ischaemum (smooth crabgrass), are especially problematic in North America and Europe.

Conversely, some Digitaria species have agricultural value. Digitaria exilis (white fonio) and Digitaria iburua (black fonio) are cultivated in West Africa as staple cereal grains, prized for their short growth cycle, drought tolerance, and nutritional profile. The grains are processed into flour and cooked as porridge or couscous. Several species also serve as forage for livestock, and their dense growth can aid soil stabilization on disturbed sites.

Management of weedy Digitaria species typically involves cultural practices such as maintaining a dense, competitive turf, proper mowing height, and pre‑emergent herbicide applications. Understanding the biology and ecology of Digitaria is essential for balancing its role as both a useful crop and a pervasive weed.