Digitaria is a genus of plants in the grass family native to tropical and warm temperate regions but can occur in tropical, subtropical, and cooler temperate regions as well. Common names include crabgrass, finger-grass, and fonio. They are slender monocotyledonous annual and perennial lawn, pasture, and forage plants; some are often considered lawn pests. Digitus is the Latin word for "finger", and they are distinguished by the long, finger-like inflorescences they produce.
The prevalent species of Digitaria in North America are large crabgrass (D. sanguinalis), sometimes known as hairy crabgrass; and smooth crabgrass (D. ischaemum). These species often become problem weeds in lawns and gardens, growing especially well in thin lawns that are watered lightly, under-fertilized, and poorly drained. They are annual plants, and one plant is capable of producing 150,000 seeds per season. The seeds germinate in the late spring and early summer and outcompete the domesticated lawn grasses, expanding outward in a circle up to 30 cm (12 in) in diameter. In the autumn when the plants die, they leave large voids in the lawn. The voids then become prime areas for the crabgrass seeds to germinate the following season.
Biological control is preferable over herbicide use on lawns, as crabgrass emergence is not the cause of poor lawn health but a symptom, and it will return annually if the lawn is not restored with fertilization and proper watering.[7] Crabgrass is quickly outcompeted by healthy lawn grass because, as an annual plant, crabgrass dies off in autumn and needs open conditions for its germination the following spring.
Digitaria violascens Link – violet crabgrass[9][10]
References
^"Genus: Digitaria Haller". Germplasm Resources Information Network. United States Department of Agriculture. 2007-10-05. Archived from the original on 2010-05-28. Retrieved 2010-11-06.
^search for Digitaria
^Kew World Checklist of Selected Plant Families
^Tropicos, Digitaria Haller
^Gilani, S. S., et al. (2003). "Taxonomic relationship of Digitaria in Pakistan". Pakistan Journal of Botany 35(3): 279–282.
^Gilani, S. S., et al. (2003)."New subspecies of Digitaria sanguinalis from Pakistan". Pakistan Journal of Botany 35(3): 261–278.
^"Weed Killer Guide". 2009. Archived from the original on 2022-11-27. Retrieved 2020-11-03.
^Klaassen, E.S.; Craven, P. (2003). Checklist of grasses in Namibia, Part 3 (PDF). South African Botanical Diversity Network. ISBN 99916-63-16-9. Archived from the original (PDF) on 21 November 2008. Retrieved 25 March 2014.
^"GRIN Species Records of Digitaria". Germplasm Resources Information Network. United States Department of Agriculture. Archived from the original on 2009-05-08. Retrieved 2010-11-06.