HPIPM:Russian thistle

Taxonomy

Domain	Eukarya
Kingdom	Plantae
Phylum	Magnoliophyta
Class	Magnoliopsida
Superorder	Caryophyllanae
Order	Caryophyllales
Family	Amaranthaceae
Genus	Salsola

Scientific Name

Salsola tragus

Scientific Name Synonyms

Salsola iberica

Salsola kali ssp. tenuifolia

Common Name

Russian thistle

Russian thistle (Salsola spp.)

Author: The Colorado Department of Natural Resources, Colorado State Parks, and Colorado Natural Areas Program - in partnership with the Division of Plant Industries in the Colorado Department of Agriculture.

Adapted from Colorado State Parks Best Management Practices weed profile for Russian thistle by Marjolein Schat, Montana State University

Identification and Life Cycle

There are several Salsola species knows as Russian thistle including S. iberica, S. kali, S. pestifer, and S. collina. The Salsola genus is in the goosefoot family (Chenopodiaceae) and the different species within the genus have different distributions. Distribution maps for the different species can be found at the USDA Plants Database. Seedlings have long fleshy leaves. Stems on mature plants are 0.5 to 3 feet tall and are rounded, bushy, and highly branched. Stems are purple and red striped. Leaves are alternate, the first leaves are long, stringlike and soft. Later leaves are short, scale-like and tipped with a stiff spine. Flowers are inconspicuous and borne in axils of the upper leaves. Each flower is accompanied by a pair of spiny, floral bracts. Fruits are small one-seeded and have winged tips. Seeds are round, black, smooth, and shiny. Roots consist of a taproot that can grow 3 feet or more in depth with extensive lateral roots.

Habitats

Russian thistle grows in disturbed or unoccupied sites. It grows on any type of well-drained, un-compacted soil with a sunny exposure. Russian thistle cannot tolerate saturated soils for extended periods of time.

Impacts

Russian thistle is well adapted to cultivated dryland agriculture, but is also found on disturbed rangeland, and wasteland. Russian thistle colonizes barren desert areas that cannot support other flora, and invades many different disturbed plant communities.

Biology and Ecology

Russian thistle reproduces by seed. Seeds germinate in spring. Plants typically flower from July through October. Seeds mature during August through November. Russian thistle seedlings are poor competitors, and do not establish well in crowded communities. One plantn can produce approximately 250,000 seeds. Seeds remain viable in the soil for less than a year. After seeds mature in the fall the plant stem separates from the root. The plant is then blown by winds, dispersing seeds as it tumbles.

Biological Control

The Division of Plant Industry’s Biological Pest Control Section has two moth species, Coleophora klimeschiella and C. parthenica, that have been studies for use as biological control agents.

Mechanical and Cultural Control

Mowing or pulling young plants can be used to control Russian thistle. However this process may have to be repeated for several years to be successful.

Chemical Control

Resistance to ALS inhibitors has been reported for Salsola iberica in Saskatchewan, Canada, as well as Washington, Montana, Idaho, Oregon, and California. For more information on herbicide resistance in S. iberica, please see http://www.weedscience.org/Summary/USpeciesCountry.asp?lstWeedID=147&FmSpecies=Go

For herbicide recommendations for specific grain rotations and weeds in Montana, please see the MSU Herbicide Chooser Tool.

Examples of herbicides that can be used to manage Russian thistle

Consult herbicide labels for additional rate, application, and safety information. Additional herbicide information can be found at http://www.greenbook.net.

Herbicide Active Ingredient trade name	Mode of Action	Product per Acre	Application Time or Growth Stage
Alfalfa
Trifluralin	Microtubule assembly inhibition
*Treflan 4EC		1.5 - 2 pints	Apply to established alfalfa during dormancy or semi-dormancy in the fall or spring before weeds emerge, or apply liquid formulations during the growing season immediately after a cutting.
Peas and Lentils
Sulfentrazone	Inhibition of protoporphyrinogen oxidase (PPO)
*Spartan 4F		2.25 - 8 ounces	Apply early-plant, pre emergence or preplant incoroporated in the spring.
Grass Grown for Seed
Glyphosate	Inhibition of EPSP synthase
*Roundup Original		24 - 32 ounces	Can be used for the following types of applications: preplant, preemergence, at-planting, renovation, site preparation, shielded sprayers, wiper applications, and spot treatments. Apply when weeds are 6 – 12 inches tall.
Small Grains
Chlorosulfuron; metasulfuron	Inhibition of acetolacetate synthase ALS (acetohydroxyacid synthase AHAS); action like indole acetic acid (synthetic auxins)
*Finesse		0.2 - 0.4 ounce	Preplant/preemergence applications are recommended for winter and spring wheat only. Postemergence (winter wheat and winter barley): Apply after crop reaches 2-leaf stage, but before boot stage. Postemergence (spring wheat and spring barley): Apply after crop reaches 2-leaf stage, but before flag leaf is visible.

The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.

References

For more information and images please visit IPM Bugwood. http://www.ipmimages.org/search/action.cfm?q=Russian%20thistle&Start=1&results=51