Annual ryegrass is a winter annual found throughout the United States that may reach 3 feet in height with a fibrous root system. Stems are often tinged red at the base, and leaves are rolled in the bud with claw-like auricles in the collar region. Leaf blades are 2-1/2 to 8 inches long, 1/8 to 1/4 inches wide, and have a membranous ligule. The seedhead is a 4- to 16-inch-long spike with spikelets that have long awns arranged alternately up the stem. The plant has a fibrous root system.
|Table 1. Effect of Sequential Herbicide Application on Annual Ryegrass Control in No-till Corn in Virginia.|
|Herbicide||Rate/Acre||Control of Annual Ryegrass1|
|2 WAT2||8 WAT3|
|Roundup||1.5 pt + 1.5 pt||76||99|
|Liberty||20 oz + 20 oz||10||50|
|Poast Plus||1.5 pt||11||65|
|Poast Plus||2.25 pt||20||69|
|Poast Plus||1.5 pt + 1.5 pt||13||68|
|Lightning||1.28 oz + 1.28 oz||4||35|
|1 Indicates visual ryegrass control (0-100%)|
2 WAT = weeks after treatment
3 Sequential treatment applied 6 weeks after initial treatment
Results indicated that levels of annual ryegrass control similar to standard treatments containing Bladex can be realized through the use of Gramoxone plus atrazine or Roundup Ultra applied alone at 1.5 or 3.0 pints per acre in combination with either atrazine or Basis. Gramoxone treatments in combination with Basis are not advisable. Initial annual ryegrass control (1 WAT, data not shown) was much lower with Roundup Ultra treatments compared to Gramoxone treatments due to their respective modes of action. Therefore, chemical choice depends upon the grower's anticipated time of planting. Using Roundup-ready corn hybrids appears to give the grower the option of applying postemergence treatments of Roundup to control annual ryegrass. Using the other transgenic hybrids, however, does not seem to provide any potential benefit.
This research was done in cooperation with Randolph Aigner, Henrico County, and Rueben L. Blanton, Amelia County.
Reviewed by Edward S. Hagood, Jr., Extension specialist, Plant Pathology, Physiology, and Weed Science.
Virginia Cooperative Extension materials are available for public use, re-print, or citation without further permission, provided the use includes credit to the author and to Virginia Cooperative Extension, Virginia Tech, and Virginia State University.
Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University, and the U.S. Department of Agriculture cooperating. Edwin J. Jones, Director, Virginia Cooperative Extension, Virginia Tech, Blacksburg; M. Ray McKinnie, Interim Administrator, 1890 Extension Program, Virginia State University, Petersburg.
May 1, 2009