Content-Length: 96681 | pFad | http://web.archive.org/web/20181219020209/http://extension.umd.edu/hgic/topics/crabgrass
(More lawn weeds) (Control Options)
Large crabgrass
Digitaria sanguinalis
Summer annual.
Grows up to 2 ft. tall; decumbent growth habit; swollen nodes. may root at nodes. Dies after the first frost in the fall.
By seed. Seeds germinate from spring through late summer.
Mowing the lawn too short. Thin turf with bare spots.
Mowed crabgass
Cultural control: Maintain healthy, dense turf that can compete and prevent weed establishment. Proper lawn mowing.
Mechanical control: Hand pulling or using an appropriate weeding tool are the primary means of mechanical weed control in lawns. This is a viable option at the beginning of an infestation and on young weeds. Hand pulling when the soil is moist makes the task easier. Weeds with tap roots like dandelions or have a basal rosette (leaves clustered close to the ground) like plantain are easier to pull than weeds such as Bermudagrass (wiregrass) or creeping Charlie (ground ivy) that spread with stolons or creeping stems that root along the ground.
General chemical control: (lawns) A granular (apply with a spreader), selective, preemergent herbicide. There are numerous products on the market. Look for a preemergent without nitrogen fertilizer. Active ingredients include: bensulide, dithiopyr (offers postemergent control on young crabgrass seedlings), pendimethalin, prodiamine, and siduron (can be applied when sowing grass seed).
A postemergent, selective herbicide that contains: Common Name: Quinclorac; Trade Name: Drive; others, can be combined with other active ingredients, Common Name: Fenoxaprop-p-ethyl;Trade Name: Acclaim Extra, others. Controls young weeds only.
Rainfall or irrigation is required to dissolve the herbicide, which is then absorbed into the upper portion of the soil and forms a barrier which kills weed seedlings. Preemergent grass herbicides have residual activity that lasts for several weeks after application. High temperatures and rainfall will decrease the length of time they remain at sufficient concentration to be effective.
Tips for application:
For a glossary of herbicide terms and additional information see: control options
Publication: (PDF) TT43-Herbicides for Crabgrass and Goosegrass Control in Turf