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Published August 04, 2009, 04:07 PM

Poisonous plant found in ND rangelands

FARGO - Several small patches of halogeton, a plant toxic to sheep, cattle and herbivorous wildlife, have been found in the Badlands area of western North Dakota, east of the Little Missouri River and north of Interstate Highway 94, by Carmen Waldo, natural resources specialist with the U.S. Forest Service in the Medora Ranger District.

By: NDSU Extension Service,

FARGO - Several small patches of halogeton, a plant toxic to sheep, cattle and herbivorous wildlife, have been found in the Badlands area of western North Dakota, east of the Little Missouri River and north of Interstate Highway 94, by Carmen Waldo, natural resources specialist with the U.S. Forest Service in the Medora Ranger District.

"Halogeton, previously unknown in North Dakota, was initially introduced during the 1930s into North America from the cold desert region of Eurasia," says Lee Manske, North Dakota State University range scientist at the Dickinson Research Extension Center. "The plant spread rapidly and became a serious problem weed in the Intermountain Great Basin Region of the western U.S. The plant thrives on the arid alkaline and saline soils in Nevada, Utah, Wyoming, Idaho, Oregon and Colorado. Halogeton is listed as a noxious weed in the states of Arizona, California, Colorado, Hawaii, New Mexico and Oregon."

Halogeton (Halogeton glomeratus (M. Bieb.) C.A. Mey.) is a member of the goosefoot family and is an introduced, warm-season, summer annual herb with horizontal spreading branches that curve upward to around 2 feet in height. The taproot can grow to about 20 inches in depth. Immature plants appear similar to young Russian thistle and kochia plants. Mature plants have red stems with small, round, fleshy, blue-green leaves about a half-inch long with a single hair protruding out of the end.

The leaf resembles a miniature sausage or wiener on a stick. Plants have small, inconspicuous yellow flowers during July through September and produce enormous quantities of seed, averaging around 75 seeds per inch of stem. Two types of seeds are produced each year. The black winged seeds, developed after mid- August, can remain viable for about a year and have a short after-ripening period that permits quick germination. The black seeds can imbibe water and germinate in less than one hour. The brown wingless seeds, developed before mid- August, are dormant at maturity. This allows the seeds to survive in the soil for 10 years or more. The seeds are dispersed by wind, water, human activities, through the digestive tract of sick animals and when dry plants break off at ground level and tumble with the wind. The germination of most seeds occurs during the late fall or early spring.

Halogeton plants contain unusually heavy concentrations of soluble oxalates, which are bound primarily as sodium salts. Concentrations of the soluble oxalates are highest in the leaves (14 percent to 25 percent) and lowest in the stems (1 percent to 4 percent) and seeds (2 percent). Most of the sodium oxalates in the stems are insoluble, so they are nonpoisonous. The content of the soluble sodium oxalates tends to be relatively high during midsummer and may exceed 30 percent in leaf samples from late August to frost. Dead plants remain almost as poisonous as the living plants.

After ingestion, soluble sodium oxalates are readily absorbed into the circulatory system. The sodium ions are replaced by calcium withdrawn from blood serum. This calcium reduction disrupts blood coagulation and nerve and muscle function resulting in staggering and muscular spasms similar to milk fever. These calcium oxalates formed in the blood are precipitated in the liver and kidneys, which then interferes with the normal function of these organs. A lethal dose of foliage at 0.3 percent to 0.5 percent of the animal's body weight can cause death within 24 hours. About 1.5 pounds of foliage can kill a sheep and about 3 to 5 pounds can kill a cow. As little as 12 ounces of foliage can be fatal to animals in poor condition. Generally, cattle develop subacute symptoms from halogeton poisoning when abundant forage is available because the bitter taste of halogeton discourages consumption of large enough quantities of foliage to cause acute symptoms and death.

Halogeton competes poorly with healthy, established perennial vegetation.

However, open areas with bare saline-alkali soils facilitate its invasion and establishment. Control can be troublesome because of the large quantity of seeds produced annually and the long survival period of the brown seeds.

"Three herbicides have been shown to effectively manage halogeton in the Great Basin Region," Manske says. "The control of young plants during June, prior to the start of flowering, is possible with 2, 4-D applied at 1 to 2 pounds of acid equivalent (1.1 to 2.1 quarts of product) per acre. If the plants are mature, the application should be 2 to 6 pounds acid equivalent (2.1 to 6.3 quarts of product) per acre to be effective. One application of tebuthiuron (Spike 20P) at 0.5 pound of active ingredient (2.5 pounds of product) per acre should provide control for three to five years. Metsulfuron (Ally XP, Cimarron, Cimarron X-tra and Cimarron Max) is effective at 0.2 ounces of active ingredient (0.3 pound of product) per acre."

There are no registered biocontrol agents for halogeton at this time.

"Halogeton has the biological ability to develop into a very troublesome noxious, poisonous plant in our western rangelands," Manske says. "However, during these early stages of invasion, eradicating it in North Dakota still is possible if decisive action is implemented before the plant population reaches crisis level."

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