Chilean mesquite tree problems

Mesquite – How To Control It

Many people view honey mesquite (Prosopis glandulosa) as a poor quality rangeland plant. However, it provides cover and food for wildlife and livestock; plus it is a legume that has the ability to fix nitrogen back into the soil. When unmanaged, mesquite can dominate a rangeland, reducing the available forage for livestock. Mesquite is very adaptable to our rangelands due to its drought tolerance and ability to grow in most soils. The primary reason that mesquite is so hard to control is due to its ability to resprout. Cutting or burning only top-kills mesquite, allowing it to resprout from the base of the stem.

Wildlife and livestock use mesquite beans as a food source in some areas. This is mainly why mesquite is easily spread across our rangelands, and, without proper diligence and control by a land manager, mesquite can quickly dominate a pasture. Mesquite beans can cause weight loss and even death if they are the primary food source for livestock.

There are many ways to control mesquite. The most effective way to control mesquite is to mechanically or chemically kill the buds at the base of the stem to prevent resprouting. This can be accomplished by root plowing, grubbing (digging up the roots of individual plants) or use of herbicides. Additional management options include the use of prescribed fire. When using herbicides, be sure to follow label directions for lawful and safe use.

One herbicide control method is to spray cut stumps with a mixture of 25 percent Remedy® and 75 percent diesel or vegetable oil, which is labor intensive, but effective. Another method is to spray stems from ground level to a height of 18 inches with a mixture of 15 percent Remedy® and 85 percent diesel or vegetable oil when the stems are less than 1.5 inches in diameter. If the stems are 1.5-4 inches in diameter, use a mixture of 25 percent Remedy® and 75 percent diesel or vegetable oil. These stem treatments can be applied any time of year. Another herbicide treatment is to spray the leaves with a mixture of 0.5 percent Reclaim®, 0.5 percent Remedy® and 0.25 percent surfactant mixed with water. The best time to leaf spray is during late spring (May-June) when the soil temperature reaches 75 degrees at a 12-inch depth. Make sure there is no leaf damage before you spray and the leaves should be a dark green color. When using herbicides to treat mesquite, it is a good idea to add 1 ounce of dye per gallon of mixture to help you identify which trees have been treated.

Velpar® is another herbicide that can be used to control mesquite. Velpar® can be applied to the soil with an exact delivery handgun applicator within 3 inches of the mesquite root collar. Apply 2-4 milliliters for every inch of stem diameter at breast height. Do not apply more than 1/3 gallon of Velpar® per acre per year. Try to avoid treating soils that are wet or expecting rain within 24 hours because this can reduce the chemical’s efficacy.

Prescribed fire is not an effective tool for killing mesquite; however, it can be used to suppress mesquite growth. It will top-kill young mesquite with “slick bark,” and a fire return interval of three to five years should keep regrowth suppressed.

The Oklahoma Chapter of The Wildlife Society will be hosting their annual meeting in conjunction with the Bollenbach Wildlife Symposium in Ardmore, Okla., and the surrounding areas on Sept.10-11, 2009. This event is open to the public, so if you’re interested, contact Steven Smith ([email protected], 580-224-6465) for more information.

The only organic control is grubbing, which requires that you get (practically) the whole root, not an easy endeavor.
Mowing always leaves a few inches above the ground, and that is generally enough for a mesquite to live indefinitely. Frequent mowing WILL, keep your place looking like it is free of brush , and can possibly be used to prevent effective seed pod formation, which would help to keep them from spreading.
As mentioned, Remedy + Diesel, definately works, but of course is not an organic method.
More organic, than above (lesser of an evil persay?) would be a cut stump method, cutting the tree to the ground, and then immediately applying diesel over the cut/exposed area, and around the base of the trunk.
Diesel is a petroleum product, but so is the stuff most all of us put in our vehicles.
Again, the most organic method is mechanical grubbing, but not something I recommend if you are on a shallow rocky soil.
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Now to clarify a few things, no, keeping the few large mesquite around does not help (contrary to what many believe). I’ve got a 10 acre field we keep in mesquite, and where the young seedlings grow, is whereever they darn well please. If you like the looks of the large mesquite, you can surely keep them, but just know that the consequence of keepin any mesquite, is always having a source for mesquite beans, and therefore new mesquite seedlings.
Secondly, no, enhancing soil health will not kill a single mesquite. Mesquite are actually/typically found growing on better soil/ecological site.
To say that improving your soil health will improve your mesquite problem, would be like me saying that improving soil health will improve your tomato problem.
Weeds & noxious brush will grow in many place where we have a difficult time growing anything else, but that doesn’t mean that they won’t grow on really good soil too!
Best mgmt method to reducing new seedling mesquite in a pasture, is to keep as much grass cover as possible. And while improving soil can possibly improve grass cover, if the grass doesn’t stay, then neither do the improvements. Ground cover is the key to reducing weeds and brush encroachment… Think of GRASS as your MULCH, in your flower bed.
Lastly, don’t mow your mesquite, if you dont have to. Doing so, makes them harder to get rid of later on. They become multi-stemmed and almost immune to chemicals that would have worked otherwise, and when the next person or yourself stops mowing, then all you have is a really ugly, unmanageable field.

Mesquite Tree

Prosopis pubescens, Prosopis velutina, Prosopis glandulosa

During the inevitable droughts and deprivations of desert frontier days, mesquite trees served up the primary food source for caravans and settlers. Mesquite beans became “manna from heaven” for the suffering men of the 1841 Texas Santa Fe Expedition said George W. Kendall (quoted by Ken E. Rogers in The Magnificent Mesquite) in his journal. “When our provisions and coffee ran out, the men ate in immense quantities, and roasted or boiled them!” During the Civil War, when groceries often ran short, mesquite beans served as passable coffee. Mesquite blooms, pollinated by bees, yield a connoisseur’s honey.

Mesquite is the most common shrub/small tree of the desert southwest. Like many members of the legume family (called Fabaceae these days), mesquite restores nitrogen to the soil. There are three common species of mesquite: honey mesquite (Prosopis glandulosa), screwbean mesquite (Prosopis pubescens ) and velvet mesquite (Prosopis velutina).

Mesquite beans, durable enough for years of storage, became the livestock feed of choice when pastureland grasses failed due to drought or overgrazing. They were carried by early freighters, who fed the beans to their draft animals, especially in Mexico.

Although often crooked in shape, mesquite tree branches, stable and durable, filled the need for wood during the construction of Spanish missions, colonial haciendas, ranch houses and fencing. Its wood served artisans in the crafting of furniture, flooring, paneling and sculpture. “Of the tree mesquite,” said Dobie, “there is one kind of yellowish wood and another of a deep reddish hue as beautiful when polished as the richest mahogany.” In some areas, mesquites provide a bountiful harvest of wood for use in fireplaces and barbecue grills.

Mesquites, requiring little water and only low maintenance, have found a place in Southwest xeriscaped gardens and parks. They not only produce beans and blooms that attract wildlife, they provide perches and nesting sites for birds, including hummingbirds.

In the frontier days, according to Dobie, mesquites were used by the Indians and the settlers as a source of many remedies for a host of ailments. Indians and settlers believed tea made from the mesquite root or bark cured diarrhea. Boiled mesquite roots yielded a soothing balm that cured colic and healed flesh wounds. Mesquite leaves, crushed and mixed with water and urine, cured headaches. Mesquite gum preparations soothed ailing eyes, eased a sore throat, cleared up dysentery and relieved headaches.

(Note: Medical studies of mesquite and other desert foods say that despite its sweetness, mesquite flour (made by grinding whole pods) “is extremely effective in controlling blood sugar levels” in people with diabetes. The sweetness comes from fructose, which the body can process without insulin. In addition, soluble fibers, such as galactomannin gum, in the seeds and pods slow absorption of nutrients, resulting in a flattened blood sugar curve, unlike the peaks that follow consumption of wheat flour, corn meal and other common staples.

“The gel-forming fiber allows foods to be slowly digested and absorbed over a four- to six-hour period, rather than in one or two hours, which produces a rapid rise in blood sugar,” Mesquite meal is sold in DesertUSA’s online store.)

Getting Acquainted with Mesquite

Mesquites, including the three species in our southwestern deserts, belong to the legume family, which ranks near the top of plants especially adapted to an arid environment. Typically, the legumes, which have woody stems and branches, produce bipinnately compound leaves (leaves with two or more secondary veins, each with two rows of leaflets). They bear flowers that have five petals, then produce abundant large seedpods that serve as a nutritious food source for wildlife. Mesquites grow wide-spreading and deep-reaching root systems that host colonies of bacteria that can fix nitrogen, one of the minerals most important to plant germination and growth.

The three species of mesquites, which include the honey mesquite, the velvet mesquite and the screwbean mesquite, share various characteristics. They range from a few feet to 10 to 15 feet in height, although the honey and velvet mesquites may reach 30 to 60 feet in especially favorable settings. They may have single or multiple-branched stems, with each plant assuming its own distinctive shape – and come armed with thorns on their smaller branches. Mesquites shed their leaves in the winter but will bloom from spring into summer, bearing small frothy-looking clusters – called “catkins” – of tiny, five-petalled, pale green or yellowish flowers, which lure numerous pollinating insects. They produce pods that contain hard and long-lasting seeds that must be scarified (cut or slit) before they will germinate. Mesquites have lateral roots that extend far beyond the canopies of the plants and taproots that penetrate well below the surface of the soil. Some mesquites may live for more than two centuries according to Thomas B. Wilson, Robert H. Webb and Thomas L. Thompson, U. S. Department of Agriculture, Forest Service, General Technical Report RMRS-GTR-8.

The honey mesquite, distinguished by smooth-surfaced leaflets, makes its primary home in the Chihuahuan Desert, east of the Continental Divide, although its outer range extends across the Sonoran Desert as well. The closely related velvet mesquite, marked by velvet-surfaced leaflets, has as its primary residence the Sonoran Desert, west of the Continental Divide. The screwbean mesquite, identified by its tightly spiraled bean pods, has established as its basic range the northern Sonoran Desert up into the Mojave Desert. Where distributions of the species overlap, the plants hybridize, often making identification difficult.

Mesquite meal or flour, is made by finely milling the seeds and pods of the mesquite tree.

Adaptations to the Desert Environment

From crown to root tips, mesquites have evolved a number of adaptations especially designed to help assure survival in the desert environment. Their thorns, sharply pointed and strong, challenge browsing by desert herbivores. (“They will not decay in the flesh or gristle as will prickly pear thorns,” Dobie said, “but will last longer than any flesh in which they become imbedded.”) Their leaves, small and wax coated, minimize transpiration (evaporation of the plant’s water into the atmosphere). During extreme drought, the mesquites may shed their leaves to further conserve moisture. Their flowers, fragrant and delicate, attract the insects, especially the bees, necessary for prolific pollination. Their seeds, abundant and protectively coated, may last for decades, serving as seed banks that improve the odds for wide distribution and successful germination.

Most notably, mesquites’ root systems give the plants a competitive botanical edge in the desert landscape. As hosts to nitrogen-fixing bacteria, they help enrich otherwise impoverished desert soils in which the plants and their progeny grow. In lateral reach, they outcompete other plants in the battle for soil moisture. In their taproots’ downward reach, they find subsurface water, sometimes 150 to perhaps 200 feet below the surface. According to the Arizona-Sonora Desert Museum Internet site, “The mesquite’s root system is the deepest documented; a live root was discovered in a copper mine over 160 feet (50 meters) below the surface.”

Range

During the Ice Ages, which lasted from about 1.8 million to some 10,000 years ago, the mesquites “coevolved with large herbivores, such as mastodons and ground sloths, which ate the pods and then dispersed them widely in their feces,” said the Arizona-Sonora Desert Museum Internet site. The mesquites found the arrangement to be ideal. The seeds became scarified by mastication, preparing them for germination. Seed parasites died when exposed to the animals’ gut juices. The seeds found moisture and nutrients in the animals’ dung. It proved to be a perfect formula for expansion.

Over time, mesquites expanded their range to correspond largely with the herbivores’ range, which extended from flood plains and washes up into prairies, mesas and mountain slopes. When the Ice Ages ended, however, the large herbivores died out, becoming extinct, and rainfall diminished. Deprived of their animal agents for distribution and faced with intensifying competition for water and nutrients, mesquites retreated to the flood plains and washes, forfeiting the higher elevation landscapes to the grasses. Further, mesquites remained contained by frequent wildfires fueled by the grasses, which recovered within a season.

When European descendants moved into the desert Southwest, mesquites found a new ally, domesticated livestock, especially cattle. The new herbivores not only ate and dispersed the pods, the great livestock herds stripped away the desert grasses, eliminating competition and wildfire fuel. In many areas, the opportunistic mesquites moved in to displace grasses. They reclaimed much of their Ice Age range, expanding from the flood plains and washes again up into prairies, mesas and mountain slopes. Mesquites grew up along the historic cattle trails, defining the routes to this day. In fact, mesquites have become established in borrow ditches along modern desert roadways traveled by cattle trucks.

Mesquites as Botanical Enemies

The mesquites’ encroachment into pasturelands and displacement of grasses has frustrated cattlemen, who unwittingly fostered the advance in the first place by overgrazing. “Because dense mesquite outcompetes grass for water and light and because mesquite groves don’t support fire, this conversion is permanent (on a human time scale) without physical intervention,” according to the Arizona-Sonora Desert Museum Internet site.

The mesquites have largely thwarted any attempt at control, including planned burns, herbicides or physical removal – all methods with a high cost and potential environmental damage.

“Fire has been used as a management tool to control mesquite distribution for decades” said Wilson and his associates. However, one authority “determined that within 5 years of a fire in southern Arizona biomass had attained preburn levels.” Mesquites may succumb to frequently repeated burns but so do native grasses, making way for imported invasive species such as the extremely aggressive Lehmann lovegrass.

Herbicides, usually applied by aircraft, have also been used for decades in attempts to control the mesquites. However, “To completely remove mesquite or at least limit its spread in open rangeland using herbicides only, multiple treatments are required; otherwise, the long-term viability of mesquite seeds and their abundance with the seed bank would ensure continual recruitment,” said Wilson and associates. Moreover, “These multiple applications could create adverse side effects to rangeland species diversity and biomass… With the attendant costs of herbicides and aerial application over large areas, a viable long-term management strategy using only herbicides may be impractical.”

Physical removal – by methods such as dozing, root plowing, chaining, roller chopping or shredding – has reduced mesquite density in pasturelands for brief periods, but the plants soon re-sprout from their bases, more dense than ever. Moreover, said Wilson and his fellow authors, “driving large mechanical equipment through rangeland can cause soil compaction, crush animals, destroy animal burrows, and uproot desirable plant species such as perennial grasses.”

“The white man,” said Dobie, “sowed with over-grazing; he is now reaping thickets of mesquites that are stabbing millions of acres of land into non-productiveness.”

Mesquites as Botanical Friends

If mesquites have arrived as intruders in the view of cattlemen of the Southwest, they have, by contrast, long been a welcome presence in the larders, livestock feed bins, workshops, gardens and medicine cabinets in the perspective of many desert residents.

Cabeza de Vaca, in his Adventures in the Unknown Interior of America (translated and edited by Cyclone Covey), said that “The Indian method of preparing is to dig a fairly deep hole in the ground, throw in the beans, and pound them with a club the thickness of a leg and a fathom and a half long, until they are well mashed. Besides the earth that gets mixed in from the bottom and sides of the hole, the Indians add some handfuls, then pound awhile longer. They throw the meal into a basket-like jar and pour water on it until it is covered

“Then all squat round, and each takes out as much as he can with one hand. To the partakers, the dish is a great banquet.”

Something that Belongs

Uninvited guest or welcome neighbor, the mesquites belong to the desert. They evolved in the desert. They play a core role in the desert ecosystem. They both provoke and benefit the people of the desert.

“It comes as near being characteristic of the whole Southwest, including much of Mexico, as any species of plant life known to the region,” said Dobie.

“I ask for no better monument over my grave than a good mesquite tree.”

by Jay W. Sharp


Mesquite meal
Desert Lil’s Cookin’ with Mesquite

Signs Of Mesquite Sickness – Recognizing Mesquite Tree Diseases

Mesquite trees (Prosopis ssp.) are members of the legume family. Attractive and drought tolerant, mesquites are a standard part of xeriscape plantings. Sometimes, though, these tolerant trees exhibit signs of mesquite sickness. Mesquite tree diseases run the gamut from bacterial slime flux to different types of soil-borne fungus. Read on for information about diseases of mesquite trees and how to recognize them.

Mesquite Tree Diseases

Your best bet for keeping your mesquite tree healthy is to provide it with an appropriate planting location and excellent cultural care. A strong, healthy plant won’t develop mesquite tree illnesses as readily as a stressed tree.

Mesquite trees require soil with excellent drainage. They thrive in full sun, reflected sun and also partial shade. They are native to North America, South America, Africa, India, and the Middle East.

Mesquites require deep watering every so often. And adequate irrigation allow the trees to

grow to their full mature height. All mesquites do well in hot weather, as long as you provide adequate water. When mesquites are water stressed, the trees suffer. If you are treating a sick mesquite tree, the first thing to check is whether it is getting sufficient water.

Signs of Mesquite Sickness

One of the common diseases of mesquite trees is called slime flux. This mesquite tree illness is caused by a bacterial infection of the sapwood in mature trees. Slime flux bacteria live in the soil. They are thought to get into the tree through wounds at the soil line or pruning wounds. In time, the affected parts of the mesquite start to look water-soaked and exude dark brown liquid.

If you want to start treating a sick mesquite tree with slime flux, remove seriously infected branches. Avoid this mesquite tree illness by taking care not to wound the tree.

Other mesquite tree diseases include Ganoderma root rot, caused by another soil-borne fungus, and spongy yellow heart rot. Both of these diseases enter the mesquite through wound sites. The signs of mesquite sickness from root rot include a slow decline and eventually death. No treatment has proved helpful for infected trees.

Other diseases of mesquite trees include powdery mildew, in which infected leaves are covered with a white powder. Signs of this mesquite sickness include distorted leaves. Control it with benomyl if you like, but the disease doesn’t threaten the mesquite’s life.

Mesquite can also get leaf spot, another fungal disease. You can control this also with benomyl, but it isn’t usually necessary given the limited nature of the damage.

In the past year, we have noticed far more branch dieback on mesquite than ever before. The dieback is occurring throughout La Paz County and all along the lower Colorado River. This dieback results in the death of the tree almost every time. We have only seen this problem in the hybrid mesquite (prosopis chilensis). This is the mesquite sold in almost every nursery in Arizona.

Why is this problem only occurring in this variety? The Chilean mesquite is the most vigorous of all mesquite and is the most branching. Most of the affected trees are between six and twelve feet tall and are almost always over-pruned. The trees weep sap and the sap form globules visible on the tree bark.

Some published information suggests that a flat-headed borer beetle enters the cambium of the tree through wounds made by pruning. The beetle larva disrupts the flow of nutrients to the branch tips and dieback is the result. We have seen no evidence of beetle adults or larvae on the tree or within the tree cambium.

The other possible reason is that this tree has too much vigor to withstand over-pruning. Pruning sends a signal to the plant being pruned to send more energy from the roots and to the buds along limbs to produce more limbs. More sap comes up from the roots producing more pressure within the cambium of the tree, and the excess sap is then forced out the tree through the wounds. Too much sap leaves the system and the result is not enough nutrients reach the terminal buds and dieback is the result. Once this dieback starts it continues until the entire limb is dead and eventually the entire tree must be removed.

Whether or not either of the two above explanations is correct, over pruning is the real problem. If you have a young Chilean mesquite, we would suggest not pruning for at least a year and then only limited pruning to correct shape or crossing limbs. Leave the small limbs on the lower part of the tree trunk. Leaving these limbs on the tree will result in a larger, stronger trunk and will not expose the tree to the problems listed above.

If you are able to find a nursery tree that has not had the lower limbs removed, buy that tree. It will be the healthiest one. If you just have to prune, maybe another tree not so prone to pruning problems would be a better choice. A good rule of thumb to remember is don’t remove more than one fourth of the canopy of any tree in one years’ time. There are correct and incorrect ways to prune any tree. We can provide information on correct pruning practices. and we have trained master gardener volunteers throughout the county who will happily show homeowners how to correctly prune a tree. Contact us at any time for plant information we can be reached at 2524 S. Mutahar Street or telephone 928 669-9843.

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