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LARGE CRABGRASS - A PROBLEM WEED 



Prasanta C. Bhowmik 



Department of Plant and Soil Sciences 



University of Massachusetts 



Common name ; Large crabgrass or hairy crabgrass 



Botanical name ; D i g i tar ia sangui nal i s (L.) Scop. 



Other names ; Hairy crabgrass, purple crabgrass, crow foot, Polish millet, 

 pigeon grass, and finger grass. 



Crabgrass is a problem weed in lawns, field crops, vegetables, and 

 turfgrasses. Orchard areas are no exception. Crabgrass belongs to the 

 genus P i g i tar i a . The word digitaria is derived from the Latin word 'digi- 

 tus' meaning finger. The flower spikes (Fig. 1) or seedheads of crabgrass 

 diverge from a single point like the fingers of a hand. The name 

 'crabgrass' is given to the grass because of the crablike branching habit of 

 its prostrate stems. 



S imi 1 ar spec i es 



The two closely related species of crabgrass in the United States are 

 large or hairy crabgrass ( Digitaria sangu inal is ) and small or smooth 

 crabgrass ( Digitaria i schaemum ). 



Origin 



Crabgrass was grown in Switzerland by the Stone Age lake dwellers. As 

 early as 2700 B.C., a form of crabgrass known as foxtail millet was grown in 

 China and considered an important food source. Prehistoric man grew 

 crabgrass in India, utilizing it in porridge and bread. 



Crabgrass was introduced into the U.S. in iS'tS by the U.S. Patent 

 Office. At that time the Patent Office (then doing work of the future 

 Department of Agriculture) elected to introduce crabgrass to American far- 

 mers to help alleviate the acute need for good forage which resulted from 

 the importation of thousands of domestic animals. It was soon forgotten to 

 promote the new introduction. 



In the late 19th Century, a wave of immigrants from Europe arrived on 

 America's shores. With them came the real invasion of crabgrass. Most 

 immigrants brought along crop seeds. The essential grain to many of them 

 was "manna grits", a variety of crabgrass and a form of millet native to 

 central Europe. 



Crabgrass thrived in its new home, producing bountiful crops, but it 

 was soon abandoned in favor of corn and wheat. Features which made crab- 

 grass a valued crop now made it a tenacious weed. Large crabgrass is 

 considered as a problem weed in 56 countries and 33 different crops in the 

 wor 1 d . 



