By Ellen H. Brisendine
If pricklypear management is on your list of projects at the ranch, then this may be about the right time of the year to take action.
There is some debate about the value of pricklypear. It is the state plant of Texas. It is edible by livestock and humans when the spines have been removed from the pads and fruits (tunas). It provides cover for various wildlife species. The plant can have a place in a healthy ecosystem on a ranch that supports a diverse wildlife and livestock population.
But too much can be a problem and some methods of pricklypear control seem to have spurred its spread and growth rather than knock it back.
Benny Martinez, South Texas Range and Pasture Specialist for Corteva, based in Bishop, says, “In many cases, especially down here in South Texas, pricklypear will encroach upon an area and make it difficult to access parts of a pasture. Ranchers may have added labor costs when they have to spend more time rounding up cattle in pastures that are full of pricklypear. On land leased for hunting, dense pricklypear can make it difficult to retrieve game animals because the dogs are not able to track through the thickets,” he adds. And thick stands of pricklypear can reduce the amount of forage and forbs that would be available for livestock or wildlife.
If you are treating a few acres, herbicide can be applied with a backpack sprayer or with a vehicle-mounted spray rig. If you are considering treating a large area of pricklypear, Martinez says aerial application of herbicide may be the most cost efficient and effective way to go.
Pricklypear, and other species you might want to manage, can grow beneath taller, possibly more desirable brush species. Use your herbicide dollars wisely and spray before those plants go through bud break and develop leaves. “Once we start getting leaves, they will intercept the herbicide and keep it from reaching the true target, which is the pricklypear,” he explains. This will be a waste of herbicide and money.
Mechanical methods, such as roller chopping the pricklypear, or chaining a pasture — dragging a heavy chain between two bulldozers across a pasture — can be used to manage the plant, but Martinez cautions that the weather has to cooperate for these methods to really work. “If you have any kind of moisture, whether it is at the time of your mechanical practice or following, pear tends to re-root. Obviously, that would turn into a bigger problem.”
Herbicide treatments for pricklypear have long been available and the plant takes a long time to show signs of decline. The newest herbicide from Corteva, MezaVue, has a much faster visible effect on pricklypear.
“MezaVue offers some benefits that we have not seen to the same degree with other existing products. The biggest one is faster response,” Martinez says. “The pricklypear is going to show symptomology much faster after being treated with MezaVue versus the historic products, such as Tordon 22K, that have a tendency of taking a longer period of time to even show any symptomology,” he says.
This slow action has been the most common complaint Martinez has heard from ranchers. “Folks call and say they sprayed a few months ago and do not see any changes. They worry that the product is not working,” he says.
The slow response of pricklypear to herbicides is due to the plant having a “very waxy cuticle. Getting the product into the plant can be a challenge,” Martinez says. “The other issue is that pricklypear is just slow growing. It tends to metabolize the herbicide slowly. Really, the key difference that we have with MezaVue is that you are getting enhanced pad activity. With Tordon 22K, we have a little bit of pad activity, but you are really relying on the plant to move the herbicide into the root.”
Consider getting some advice on pricklypear control from a landowner or Range Specialist who you think has some experience.
“Talk to someone who ranches in the same environment and who has some experience with brush or weed treatments. They will give you good advice on how to treat your target plant, such as pricklypear, but they will also help you identify other problem plants that can be treated at the same time. They may remind you to take a broader look at the problem plants to treat, and not just focus on one species.”
Monthly Chores — Fall 2018 Rains May Have Supported More Weed Seedling Survival
Benny Martinez, with Corteva, says that the unusual rainfall in the fall of 2018 may have helped more weed and brush seedlings to survive, resulting in a heavier weed and brush load on pastures and rangeland.
“In mid-December, I noticed seedling recruitment was at an all-time high,” Martinez says. “Typically, we will have periods of drier weather that tend to control seedling plants. Seedlings do not have the vigor to sustain their life when rain events are spread out over longer periods of time. Some of those seedling plants tend to die off.
“In my area, I saw more seedling weeds surviving because they had adequate moisture. I also saw winter weed germination really exploding in my part of South Texas,” he says.
Martinez says that several species of thistles were sprouting much earlier than usual and may be a more prevalent problem in 2019.
The unusual rainfall in the fall of 2018 also may have caused unusual plants to sprout this year. Martinez says one such plant to watch for is Berlander Lobelia.
Lobelia is a toxic plant that may be grazed by cattle such as weaned calves that have not come across it before. “Since they do not know any better, they tend to graze on lobelia and you get this issue with toxicity. Some of those unusual events like these continuous rain events are the trigger for some of those species.”
Goldenweed — Not Toxic, but a Bad Neighbor
There are plants on the rangelands that are bad neighbors. Known as allelopathic plants, they produce biochemicals that keep other plants from reproducing.
In South Texas, there are two species of goldenweed (Common goldenweed, Iscoma coronopifolia and Drummonds goldenweed, Iscoma drummondii) that are allelopathic. They are not toxic to livestock or wildlife, but Benny Martinez, South Texas Range and Pasture Specialist for Corteva, says, “I’ve never seen any indicators from a wildlife standpoint or a cattle standpoint that the plant is actually browsed.”
Martinez suggests that ranchers keep goldenweed in mind when developing a herbicide treatment plan this spring.
If the herbicide works as expected on other unwanted species but does not reduce the goldenweed plant population, you may be clearing the way for this plant to encroach on your pastures.
“Goldenweed has a great ability to compete because of the allelopathic qualities. Its ability to encroach is pretty good because its defense mechanism allows it to compete against other plants. Goldenweed can suppress other plants, which allows it to capitalize on more of the nutrients and more of the moisture available in a given year. It definitely has the upper hand in competing against other species,” he says.
Treat Pricklypear is excerpted from the February 2019 issue of The Cattleman magazine. Join today to start your subscription.
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