Crabgrass and goosegrass are two of the most prevalent turf nuisances in the country. Here are a few tips LCOs can use to identify and control these troublesome grassy weeds.
Crabgrass
Know your enemy:
- Upright-growing, summer annual grassy weed that grows in patches;
- Yellowish-green in color;
- As it germinates, the wide leaf blade is generally wider than turfgrasses;
- Large crabgrass features hairs on the leaves;
- Smooth crabgrass has a smooth leaf blade;
- Begins to germinate when soil temps warm up to 55 degrees;
- Look for crabgrass first in south-facing slopes, south sides of buildings and turfgrass around and near concrete where soils are likely warmer;
- Thrives in compacted soils; and
- Competes with turf during the summer season. As crabgrass dies in the early fall, it leaves voids in the turf.
Combat strategy:
- Cultivate healthy, dense turf through a solid aeration and fertilization program and by addressing insect or disease issues promptly;
- Apply preemergent herbicides before germination (mid-February to mid- to late-March);
- Look for preemergent herbicides with active ingredients dithiopyr, indaziflam, oxadiazon, prodiamine and pendimethalin;
- Postemergent herbicide active ingredients include fenoxaprop, fluazifop, mesotrione, quinclorac, sethoxydim, topramezone and more recently, pinoxaden; and
- Single or split applications can be effective, depending on the severity of the growth.
Goosegrass
Know your enemy:
- Low-growing summer annual grassy weed;
- Lighter green in color than healthy turf;
- Broader leaf blades;
- Grows out from a whitish, folded stem from a single center point, emanating out into a “wagon-wheel” pattern;
- Found in thinner turf areas and compacted soils;
- Has a fibrous taproot; and
- Germinates 4-6 weeks after crabgrass.
Combat strategy:
- Cultivate healthy, dense turf through a solid aeration and fertilization program and by addressing insect or disease issues;
- Irrigate turfgrass deeply and infrequently — frequent, light watering encourages goosegrass growth;
- Apply preemergent products with active ingredients dithiopyr, indaziflam, oxadiazon, prodiamine and pendimethalin; and
- Postemergent products with the active ingredients fenoxaprop, foramsulfuron, mesotrione, sulfentrazone, topramezone and products that combine several herbicides are also effective.
Sources: Gil del Rosario, market development specialist at Corteva Agriscience, Agriculture Division of DowDuPont, and Jay McCurdy, Ph.D., assistant professor and turfgrass extension specialist, Department of Plant & Soil Sciences, Mississippi State University.
