Digitaria genus includes around 300 plant species, distributed in the tropical and subtropical regions of both hemispheres. Thirteen described species occur in the state of Sao Paulo, Brazil, with visual differentiation being difficult to be made in the fields due to their great morphological similarity. The species Digitaria nuda, D. ciliaris, D. horizontalis and D. bicornis, popularly known as crabgrass, are weeds commonly found in the sugar cane production fields in São Paulo. Cases of cab grass control failure have been reported by producers, likely related with weed community changes as a result of the selection of some crabgrass species tolerant to herbicides previously recommended for their control. It has been suspected that these selected populations are constituted by different crabgrass species, notably D. nuda, which has higher tolerance levels to some products. Understanding the dynamics of the weed species Digitaria genus (crabgrass) population and its mechanisms of tolerance to some herbicide groups will help outline management recommendations for these weeds, avoiding or delaying their manifestation. Identifying the species that occur in sugar cane producing areas will promote the correct herbicide choice, according to the infesting species, thus increasing the chances of successful control.
Digitaria spp.; tolerance; selection; sugar cane; weeds
