Mesquite is one of the biggest enemies faced by southwestern ranchers. The bushy, deep-rooted plant populates pastures by the millions across much of Texas, New Mexico and Oklahoma, robbing grass of precious water and limiting much-needed grazing. Its thorns can injure cattle and horses. And they’ve done their damage on more than one pair of chaps.
But there’s finally a mesquite management program that can help ranchers obtain stronger and more consistent control of the rangeland menace. Sendero® herbicide from Dow AgroSciences is enabling ranchers to obtain better grazing from perennial grasses that are the lifeblood of most cow-calf or stocker operations.
Native grasses are in a constant battle with mesquite for water and soil nutrients. And in stressful conditions, like the droughts of 2011 and 2012, mesquite becomes more of a resource robber.
Dr. Charles Hart, range and pasture development specialist with Dow AgroSciences in Stephenville, Texas, conducts rangeland research to help producers get the most out of their forage through better weed and brush control. For southwestern cattlemen and women, much of his attention is aimed at controlling mesquite.
“The drought took a significant toll on shallow rooted plants like perennial grasses and forbs,” Hart says. “We had a tremendous amount of perennial grass die off. Unfortunately, what that does is promote mesquite. Mother nature wants to fill a void. The most opportunistic plants want to take over. A lot of times that means mesquite.
“Now, mesquite will show affects of drought. It will drop its leaves and leaves will turn yellow. But the plant goes into a safe mode and waits for better conditions. It is well adapted to drought.”
In attempts to control the pesky plant, many ranchers have used a herbicide program in conjunction with controlled burning and mechanical removal. Moderate success has been seen. But due to herbicides being sensitive to climate and environmental conditions, control has ranged from 40% to 80% kill, with no sure treatment plan to regularly reach the upper levels of mesquite management.
“We’ve needed to reduce the variability of control,” Hart says. “We have conducted some five years of research to develop Sendero to provide the end user with a herbicide that will provide consistent control. We want that product to produce results that are up to that rancher’s expectations as many times as possible.
“Since Sendero was released into the market in 2012, we’ve been able reduce the variability in control, increase the amount of control and provide a product that more times that not is going to give you what you expect.”
The revolutionary herbicide provides 15% better control and a consistent 70-80% control rate. “With the right conditions, you should be able to kill and control 7-8 out of 10 plants that are treated. They should be root dead,” Hart says.
Overcoming Mesquite Resilience
“Mesquite is able to do things in the environment that other plants aren’t able to do,” Hart says. “It can survive on little water. It can send its roots down as far as needed in order to get water. It’s a very prolific seeder, so it’s going to reproduce itself through seed. It’s just well adapted the area it lives in.
“It’s ready for anything we can throw at it; freezes, droughts, floods, you name it. It’s resilient to all of those. But Sendero helps range managers overcome that resilience.”
Best control results are normally seen when the soil temperature is 75 degree or warmer at least 12 inches deep. “If temperatures are below that 75 degrees, the plant is not metabolizing,” Hart says. “The herbicide will have difficulty entering the root system.”
In pastures farther south, treatments can be made as early as mid-May. In order to obtain the best control in North Texas, southern Oklahoma and some northern New Mexico regions, it may be as as late as mid-July before soil temperature is warm enough for treatment.
“We have about the same window of mesquite herbicide application as we’ve always had,” Hart says. “Ranchers will see best results when a plant is healthy and there’s a lot of leaf growth. You might think it’s easier to kill a weak tree than an unhealthy tree. It’s just the opposite with mesquite. The mode of entry of this herbicide is through the leaf. The more leaf you have on the plant, the more chemical you get into the plant.”
Hart says a typical Sendero application rate is 28 oz./per acre mixed with 5 gal. of water and a labeled rate of a surfactant. With that prescription, broadcast aerial application of small droplets should provide ideal penetration into leaves. A spot spray program may be needed in a maintenance control system.
Application should be made between 42 and 63 days after bud break. No applications should be made during bean elongation, which is normally 63 to 72 days after bud break. Treatment can resume after that up to 90 days after bud break.
Hart says soil moisture should be sufficient for good growth. Treatment should not be made just after a heavy rainfall of a-half inch or more. Relative humidity should also be 25% or higher.
“Mesquite management is a long-term relationship,” Hart says. “You must have a follow-up plan. There is no silver-bullet for mesquite control. It’s more of mesquite management. You’re going to have new seedlings come in. Mesquite is going to re-invade.
‘It’s cheaper treat mesquite when it is young. Once you get rid of a mature population, the objective is to go back in and retreat periodically to control new plants when they are young.”
Know your mesquite varieties
In much of Texas or southern Oklahoma, Honey mesquite is the common variety. Further west, past the Midland-Odessa region and into New Mexico, Western Honey mesquite is more common. Even further west is Velvet and Screwbean mesquite.
“Those more western varieties are more difficult to control,” Hart says. “They are shorter plants and don’t have as much leaf growth. So you really need to know which variety of mesquite you have in order to obtain the best control.”
Along with mesquite control, Sendero may also provide additional weed and brush control. Specifically, Sendero combines two molecules discovered and developed by Dow AgroSciences for use on rangeland and pastures: aminopyralid and clopyralid.
Aminopyralid is one of the ingredients in both GrazonNext® HL herbicide and ChaparralTM herbicide. Both products have proven effective in weed control and brush suppression. Clopyralid is the single active ingredient in Reclaim® herbicide, which has been a popular mesquite control material.
“With the high cattle prices we’re finally seeing, it’s important that cow-calf and stocker programs get the most out of their perennial grasses,” Hart concludes. “A good mesquite management program, one that can help ranchers obtain the most gain from their cattle, is important, especially during drought conditions.
“With this new Sendero herbicide program, ranchers have a better tool to keep mesquite problems under control.”