Summer grass (Digitaria sanguinalis and Digitaria Cilaris).
Crabgrass is a soil indicator of acid soil pH, and a major problem for thin and weak sports fields and lawns. It grows rapidly at high temperatures and high humidity. This weed spreads aggressively, and crowds out desirable grasses.
Summer Grass Identification.
Crabgrass spreads from seed as well as stolons and the seed remains dormant in the soil for several years.
Classification: Monocot
Height: Digitaria grows up to 30cm in height.
Leaf Length: The leaves of Summer Grass are 5-15 cm long.
Comments: The leaves of Crabgrass are covered in coarse hairs.
Habitat: Summer Grass has poor drought tolerance and grows in full sun and shade. Its natural habitat is in sandy or sandy loam soils. However, you often find it next to driveways or pathways, and once it established it is tolerant of hot, dry, compact soils.
How to Remove Summer grass weed from your lawn.
Cultural control of Summer grass:
Chemical Control:
The key to manage Crabgrass is stopping seed production. Even though selective post-emergent summer grass herbicides are available, your best option is to use a pre-emergent herbicide.
Pre-emergent Control.
Pre-emergent herbicides such as granular pre-emergents like Onset 10GR, Echelon, Echelon Duo and Freehand or liquids like Barricade, Pennmag, Dimension, and Battalia will control Digitaria and Summer grass. Use these at the correct rate and with the right timing to get the best results.
Apply pre-emergent herbicides before germination occurs and when soil temperatures stabilize at 13°C for several consecutive days. Interestingly Dimension Herbicide also provides post-emergent control up to the 1-tiller stage.
Depending on where you are, split applications at half the high label rate almost always improve Crabgrass control in comparison to a single application at the high use rate. Aim to make the second application 4-6 weeks after when you expect Summer Grass to germinate.
Post-Emergent Control.
For post emergent control of Summer Grass use ProForce Geronimo (MSMA) or Quinstar (Quinclorac). For the best results with Quinclorac use Voltage MSO adjuvant.
With post-emergents, if the Crabgrass has tillered you will need two applications, 2 or 3 weeks apart, and you will get better results against smaller plants that have yet to tiller.
Be aware that injury is likely to occur if you use these when temperatures are greater than 29°C.
Dithiopyr (Dimension) is another option for post-emergent Summer grass control in warm- and cool-season grasses. Turfgrass managers primarily use Dimension for pre-emergent Crabgrass control, but applications in the Spring have the potential to provide early-postemergent control. Dimension must be applied to seedling Summer grass for best results.
Applications to Summer grass that has already tillered give variable post-emergent control in the early Summer. You should irrigate within 24 hours to reduce losses through volatilization in late Spring or Summer.
