Plant Industry - Plant Protection Section

Itchgrass

Itchgrass (Rottboellia cochinchinensis) is a Federal and state Noxious Weed in North Carolina. The weed is a native of India, and is a very competitive weed in crops.  It is often found on roadsides. It was initially introduced to the US as a crop seed contaminant and has spread by means of equipment, machinery, and vehicles. This particular weed is not only invasive, but can cause skin irritation when the person comes in contact with it because the hairs on the leaves mimic fiberglass.

Description

Itchgrass is an annual grass that grows upright to 12’ tall. The stems and leaves are covered with stiff hairs that irritate the skin. The leaf blades are 6-18” long, 0.2-0.8” wide, and flat. The unique seedhead is the best way to identify this plant, it is a jointed, cylindrical spikelet that grows between1-6” long. Seed production in North Carolina starts about 6-7 weeks after emergence and continues throughout the growing season (May through November).

There are three characteristics to use for identification of this grass:

1. The plant has anchor roots that support the plant.
2. The seedhead is distinct because it is jointed and the segments will break off when you touch them.
3. The fiberglass hairs are easy to see, and will cause skin irritation if gloves and long-sleeves are not worn.

This weed can occur in agricultural areas, grasslands, well-drained areas, and along roadsides. Itchgrass tolerates shade and is able to thrive in both full sun or shade environments. Itchgrass is considered to be one of the worst invaders of sugarcane in the world (causing up to 70% of losses in some areas). The weed poses a threat to other crops such as corn, cotton, peanuts, upland rice, and other crops found in tropical regions. It is thought that this plant was introduced into Florida in the early 1900’s, and it is widespread throughout Louisiana, Georgia, Alabama, Mississippi and Arkansas.

Itchgrass growing along the edge of a corn field in Robeson County, NC

History

The verification of itchgrass in North Carolina was made on a farm in Robeson County during the fall of 1984.  It is thought that the weed came to the state on railroad cars, but this has never been confirmed. In 1985, the weed was present along 7 miles of railroad right-of-way in four locations, and on five farms.  The total infested acreage was 306 acres of cropland, and 15 acres of non-crop area. From 1985 to 1988 an intense eradication effort was carried out that included intense scouting of cropland, idle areas and roadsides.  Infestations were then fumigated or treated with herbicides. In November of 1988 only a few plants were found in the county, and the infestation was considered eradicated.

In 2008, a full 20 years after it was declared eradicated, itchgrass was again found in the Robeson county.  It was found growing in some of the exact same sites as the infestations in 1985, but has since spread to a few new locations within the county.

Current Situation

Robeson county is the only county quarantined in the state.  The North Carolina Department of Agriculture serves as the lead agency for the regulatory weed programs in the state, and administers the survey, control and quarantine activities regarding itchgrass.  From 2008 until 2016 the NCDA&CS has carried out survey, quarantine and eradication activities.  The NC Department of Transportation has been an active partner in the effort, providing help to spray pre-emergent and post-emergence herbicides to the roadsides that are infested. The NC DOT has also provided and posted signs on the affected roadsides that state "DO NOT SPRAY/DO NOT MOW". If you see these signs, please do not mow the roadsides.  This will spread the seeds around the road, but they might also be carried on your equipment to a new location.

The known infestations can be summarized on the following maps:

Overview of Itchgrass Treatment Locations:

Site 1A & 1B: Chicken Road and Dew Road

Site 2: Blue Pate Loop Road and US HWY 301

Sites 3A, 3B, 3C, & 3D: Williams Pond Road, Brown Farms Road, and Cotton Valley Road/Echo Road

Site 4: Highway 501 (Old NC 130) near Salem Drive

Conclusion

Your help is needed to help us find and control new infestations of this plant.  If you know of a population of this plant that is not indicated on the maps above, please contact the NCDA&CS Weed Specialist at bridget.lassiter@ncagr.gov or (919) 707-3749. To report this invasive and others, please call 1-800-206-9333 or by email: newpest@ncagr.gov