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Federal Noxious Weed TDA Noxious Weed
TPWD Prohibited Exotic Species Invasive Plant Atlas of the USNOTE:
means species is on that list.
Rottboellia cochinchinensis
Itchgrass
Synonym(s): Rottboellia exaltata
Family: Poaceae (Grass Family)
Duration and Habit: Annual Grass/Grasslike
Photographer: USDA APHIS Archives
Source: USDA APHIS, Bugwood.org
Description
Itchgrass is characterized by pale, green-colored foliage, brace roots near the base of the plant, a cylindrical spikelet seedhead and siliceous hairs on the leaf sheath that can penetrate and irritate the skin. It grows erect and up to 4m tall or more. The inflorescence is a cylindrical raceme that is 3-15 cm long. The floral units consist of a sessile spikelet, pedicellate spikelet and internode. The pedicel is fused to the swollen floral internode. The spikelets are awnless, 3.5-6 mm long, and 2.5-3 mm wide. The floral units separate and fall as soon as they mature, from the top of the raceme downwards.
Native Lookalikes: Currently no information available here yet, or there are no native Texas species that could be confused with Itchgrass.
Ecological Threat: Called itchgrass because it has brace roots near the base of the plant, a cylindrical spikelet seedhead, and siliceous hairs on the leaf sheath that can penetrate and irritate the skin. Strahan et al. (2000b) states that, " R. cochinchinensis is rated among the worst weeds in the world and is considered a serious problem in soybean (Glycine max), corn, cotton (Gossypium hirsutum), peanut (Arachis hypogaea), upland rice (Oryza sativa), and other crops in tropical regions of the world. In Louisiana,it is a major weed problem in sugarcane (Saccharum spp.), soybean, and corn."
Biology & Spread: Individual plants produce 2000 to 16,000 seeds that are shed as soon as they mature. Seed can be spread from infested areas to non-infested areas by birds, flood water, rodents, and farm machinery. The spread of R. cochinchinensis in Louisiana has been attributed in part to movement of equipment and road matting materials used during the extensive oil exploration that occurred in the late 1970s and early 1980s. By 1980, the weed infested 38 Louisiana parishes covering about 80,940 hectares.
History: Introduced in the early 1900s into tropical America, as a potential pasture grass, and since the 1960s has been spread widely by contaminated rice seed, agricultural equipment and along transport routes in Central and South America, the Caribbean, and in the Gulf Coastal USA.
U.S. Habitat: Itchgrass grows within croplands, along roadsides and in other open, well-drained sites. It is an important species in old field succession but it can be found in wet places, and even in shallow water. It survives in habitats with full sun, moderate shade, or nearly the full shade of thickets and forests.
Distribution
U.S. Nativity: Introduced to U.S.
Native Origin: Africa, Asia, and Australia
U.S. Present: AR, FL, GA, IN, LA, NC, PR, TX
Distribution in Texas: Along the I-10 corridor with more reports in eastern Texas.
Mapping
Invaders of Texas Map: Rottboellia cochinchinensis
EDDMapS: Rottboellia cochinchinensis
USDA Plants Texas County Map: Rottboellia cochinchinensis
Native Alternatives
Management
Mechanical: Itchgrass can be controlled through burning, then a shallow plowing to encourage seed sprouting, followed by a deep plowing to bury sprouts. It may be necessary to allow fields to be fallow a year or two, followed by another burn to ensure control.
Chemical: Trifluralin and pendimethaline can be applied to soil as pre-emergent control and glyphosate or other effective post products can be used.
Biological: Headsmut of the correct variety can be used to create a bioherbicide.
Text References
Alves, P. L. 2003. Identification and characterization of different accessions of itchgrass (Rottboellia cochinchinensis). Weed Science 51: 177-180.
Bowen, B., K. Johnson, S. Franklin, G. Call, and M. Webber. 2002. Invasive Exotic Pest Plants in Tennesee. Journal of the Tennessee Academy of Science 77(2): 45-48.
Freshwater IT, Benson AJ, Hall TF, 1986. Itchgrass Rottboellia cochinchinensis-Burdekin infestation and legislative control program. Proceedings of the Australian Society of Sugar Cane Technologists, 8:155-160.
Holm LG, Plucknett DL, Pancho JV, Herberger JP, 1977. The World's Worst Weeds. Distribution and Biology. Honolulu, Hawaii, USA: University Press of Hawaii.
Millhollon RW, 1980. Itchgrass -- a weed of world-wide concern. Sugar Journal, 43(7):16.
NAPPO (North American Plant Protection Organization). 2003. Pest Fact Sheet: Rottboellia cochinchinensis (Lour.) Clayton. NAPPO-PRA / Grains Panel Pest Fact Sheet.
Strahan, R. E., J. L. Griffin, D. B. Reynolds, and D. K. Miller. 2000a. Interference between Rottboellia cochinchinesis and Zea mays. Weed Science 48:205-211.
Strahan RE, Griffin JL, Jordan DL, Miller DK, 2000b. Influence of adjuvants on itchgrass (Rottboellia cochinesis) control in corn (Zea mays) with nicosulfuron and primosulfuron. Weed Technology, 14:66-71.
Online Resources
Global Invasive Species Database (http://www.issg.org/database)
https://www.cabidigitallibrary.org/doi/10.1079/cabicompendium.47782
https://www.tnipc.org/invasive-plants/plant-details/?id=123
Search Online
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USDA Plants: Rottboellia cochinchinensis
Invasive Plant Atlas of the United States: Rottboellia cochinchinensis
Bugwood Network Images: Rottboellia cochinchinensis
