Dallis grass – Paspalum dilatatum

Weed Seed - Dallis grass (Paspalum dilatatum)

Dallis grass is an invasive turf grass that is problematic in golf courses, sports fields and lawns. This weed negatively affects the appearance, texture, and playability of these surfaces. Herbicide application is required to control this pest, as mowing and digging it out of the soil do not successfully manage the weed.

Where it's found

Dallis grass has not been found in Canada. Native to South America, dallis grass is currently established in tropical and southern Africa, Asia, Australia, southern Europe, New Zealand, and across the southern United States. Plants can be found in wet areas, including seashores, swamps, lawns, roadsides, pastures, and irrigation ditches. It can also be found on professionally managed turf grass and lawns.

What it looks like

Dallis grass is a perennial grass. Plants grow as coarse clumps; its stems and leaves grow upright to over 1 m tall. Leaves are smooth with a prominent mid-vein. Small hairs may be present at the base of the blade. Seed heads have 3–5 spikes branching from the centre.

How it spreads

Dallis grass plants produce many seeds that are spread by water, lawn mowers, humans and pets. The plant is commonly spread to new areas through contaminated turf grass seed. Once established, its seeds are naturally dispersed.

Legislation

Dallis grass is regulated as a pest in Canada under the Plant Protection Act. It is also listed as a prohibited noxious weed on the Weed Seeds Order, 2016 under the Seeds Act. Importation and domestic movement of regulated plants and their propagative parts is prohibited.

What you can do about it

  • Maintain healthy and diverse pastures.
  • Use clean, high-quality seed that is certified if possible.
  • Ensure machinery, vehicles and tools are free of soil and plant parts before moving them from one area to another.
  • Contact your local Canadian Food Inspection Agency (CFIA) office if you suspect you have found this invasive plant. The CFIA will follow up and determine if further action is needed.

To find out more, visit www.inspection.gc.ca/invasive.

Dallis grass invasion on turf
Dallis grass invasion on turf
Attribution: John D. Byrd, Mississippi State University (Bugwood.org)
Dallis grass spikelets
Dallis grass spikelets
Attribution: Barry Rice, sarracenia.com (Bugwood.org)
Dallis grass panicle
Dallis grass panicle
Attribution: Barry Rice, sarracenia.com (Bugwood.org)
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