Johnny Morgan | 9/28/2018 1:20:56 PM
(09/27/18) FRANKLINTON, La. — A group of landowners attended the first of two workshops on Sept. 25 to hear about controlling the invasive cogongrass that has entered the state.
Whitney Wallace, AgCenter forestry and wildlife resource agent, said the meeting held at the AgCenter Southeast Research Station was designed to make people aware of how difficult it is to get rid of this grass once it takes root.
“Cogongrass came into the U.S. at Mobile around 1911 in packing material from Asia and has continued to spread throughout the South,” she said.
The grass was introduced into Florida, Alabama and Mississippi for erosion control and was tried as a forage, which didn’t work.
“This grass is so prolific that one plant can produce thousands of seeds and can be dispersed over 15 miles by wind and through its roots,” she said.
The grass was first discovered in Washington Parish in 1990 and has continued to flourish due to the favorable climate.
Cogongrass can adapt to any soil type and is sun- and shade-tolerant, Wallace said.
Often, cogongrass is mistaken for Johnsongrass, but one telltale sign that it isn’t is the midrib is offset.
This grass normally grows to a height of about 3 feet, but can grow as tall as 6 feet.
So far the only animals known to prefer the grass is swine. “Others animals avoid it because the high silica levels causes it to be rough and unpalatable,” Wallace said.
Another feature of the grass is that its rhizomes are sharp, so it should not be handled without gloves.
Brent Cutrer, forest health program director with the Louisiana Department of Agriculture and Forestry, said a treatment plan is currently being implemented with the help of the U.S. Forestry Service to slow the progression of the plant.
“Research in Alabama has determined the grass can be controlled with two chemicals, glyphosate and imazapyr,” Cutrer said.
AgCenter dairy specialist Gary Hay said the other forms of control include deep tillage and spot treatments in pasture situations.
“When using imazapyr, you want to be careful to not get too close to hardwoods because it will kill the trees if the concentration is too strong,” he said.
Hay said there are no restrictions on imazapyr in a pasture situation, but there are some restrictions with glyphosate. “When using glyphosate in pastures, the cattle can’t be slaughtered for 30 days after ingestion of pasture treated with the chemical.”
Cutrer said the treatment program is free to landowners and consists of a three-year contract to inspect and treat for the grass.
“The contract is nothing really serious,” he said. “It just allows us access to your property and it can be canceled by the landowner at any time.”
If a landowner decides to enter the contract, their property will be monitored and treated for three years. If at the end of that time there is no sign of the cogongrass, the monitoring and treatment will end.
“But if at the end of the three-year period the grass is still appearing, the process will continue for another three-year period,” Cutrer said.
Currently, cogongrass has been found in 365 spots on about 70 acres in the state, with the highest infestations in Washington and St. Tammany parishes.
The next cogongrass workshop will be held at 6:30 p.m. on Oct. 2 at the Kentwood Co-op at 74219 Highway 1054 in Kentwood.
LSU AgCenter forestry and wildlife resource agent Whitney Wallace shows the invasive cogongrass that is taking root in south Louisiana at a workshop held at the AgCenter Southeast Research Station on Sept. 25. The meeting was designed to make people aware of how difficult it is to get rid of this grass once it takes root. Photo by Johnny Morgan/LSU AgCenter
Brent Cutrer, forest health program director with the Louisiana Department of Agriculture and Forestry, discusses the treatment plan currently being implemented with the help of the U.S. Forestry Service to slow the progression of the invasive congongrass in the state. Photo by Johnny Morgan/LSU AgCenter
LSU AgCenter dairy specialist Gary Hay discusses ways to control the invasive cogongrass with deep tillage and spot treatments in pasture situations during a workshop held at LSU AgCenter Southeast Research Station in Franklinton on Sept. 25. Photo by Johnny Morgan/LSU AgCenter