HPIPM:Common lambsquarters

Taxonomy

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

Scientific Name

Chenopodium album

Common Name

lambsquarters

Common lambsquarters (Chenopodium album)

Compiled by Steve Lackman, Montana State University, Yellowstone County Extension

and Marjolein Schat, Montana State University from the following sources:

http://www.plants.usda.gov/java/profile?symbol=CHAL7

http://glyphosateweedscrops.org/Info/GWC-11.pdf

http://www.colostate.edu/Dept/CoopExt/4DMG/Weed/lmbqrtrs.htm

http://www.msuweeds.com/michigans_worst_weeds/common_lambsquarters/

http://www.entomology.wisc.edu/mbcn/fruit605.html

http://www.hort.iastate.edu/gluten/?pdf/grnhsechr.pdf

Identification and Life Cycle

Common lambsquarters (Chenopodium album) is a member of the goosefoot family (Chenopodiaceae), which also includes spinach and beets. Common lambsquarters is a summer annual. As a seedling, common lambsquarters has two long, linear-shaped cotyledons, and the first ovate-shaped true leaves are opposite. True leaves eventually become more distinctly alternate and may be purplish on the underside with both surfaces covered with white granules or a mealy substance. Mature plants have broadly triangle-shaped leaves with irregular, shallow-toothed margins. The stems can be green or reddish, are grooved, and can be smooth or hairless. Mature plants generally reach a height of 2 to 6 feet. At flowering, very small, green or gray-green flowers are tightly clustered at the tips of stems and branches. These flowers turn into seeds with a thin, papery covering. Seeds are smooth and shiny seeds. The majority of seeds are black and a few are brown. Brown seeds germinate readily, while black seeds are more dormant.

Habitats

Except for extreme deserts, common lambsquarters is found throughout most of the United States. Common lambsquarters prefers well-drained soils with high levels of nitrates, but can grow in compacted soil as well.

Impacts

Due to its early emergence and rapid growth rate, common lambsquarters is a successful competitor with many crops. However, as with most weed species, the exact degree of common lambsquarters competition is determined by weed density, the relative time of crop and weed emergence, and, the environment. In addition to competing for nutrients, moisture, and light, green common lambsquarters stems can hamper crop harvest by clogging up combines. Furthermore, common lambsquarters is a host for several crop diseases, including alfalfa mosaic virus, cucumber mosaic virus, bean yellow mosaic virus, clover yellow vein virus, potato virus, soybean mosaic virus, tobacco etch virus, turnip mosaic virus, and watermelon mosaic virus.

Biology and Ecology

Common lambsquarters is a summer annual that can emerge throughout the summer. Emergence begins before 150 degree days (GDD, base temperature 50°F). Spring-emerging common lambsquarters plants generally flower and set seed in late summer and fall. Later emerging plants can reach the reproductive stage in as little as 6 weeks. Prolonged drought may trigger early maturation. Common lambsquarters is primarily self-pollinated, although wind can cause some cross-pollination. This plant only reproduces by seed, and once plants flower, they set seed over a relatively short period before they die. An average common lambsquarters plant can produce more than 70,000 seeds. The seeds also can survive well in the digestive tracts of cows, sheep, and horses, so manure is considered a possible source for introducing seed. Under certain conditions common lambsquarters seeds can remain viable in the soil for several decades. Most seeds require some time before they are ready to germinate. Light and strong day and night temperature fluctuations increase common lambsquarters seed germination.

Management Approaches

As an annual plant, management should be directed towards preventing flowering and seeding. However, due to the prolonged emergence period this may be difficult.

Biological Control

Although several arthropods will feed on common lambsquarters seeds on the soil surface, there are no specific arthropod biological control agents available for this weed. Corn gluten meal has been found to reduce survival and root growth of common lambsquarters. For more information on ongoing corn gluten meal research please see http://www.hort.iastate.edu/gluten/?pdf/grnhsechr.pdf.

Mechanical and Cultural Control

Cultural practices that help control common lambsquarters include anything that makes the crop more competitive and reduces the success of the weed. Such practices include selecting crops with quick emergence, altering planting dates relative to weed emergence, planting to narrow rows and using higher seeding rates for greater crop competition, placing fertilizer with the crop (not the weed), and implementing crop rotations that discourage summer annual weed success. Late seeding in particular can give some control because common lambsquarters tends to germinate early in the season and those seedlings are killed through soil preparation or with a burndown herbicide. Underseeding a legume cover or forage crop in the small grain, or after harvest, can compete effectively with common lambsquarters if the grain and cover crops are dense and vigorous. Mechanical weed control operations, such as rotary hoeing and row cultivating can effectively control seedling weeds.

Chemical Control

There are a number of chemical control options available for common lambs quarters. Please see herbicide labels for tank mix information. There have been numerous reports of Photosystem II inhibitor resistant populations of common lambsquarters in Europe, and the United States. In 2001 ALS inhibitor resistant populations were reported in Michigan and Ohio. For a complete listing of reports of herbicide resistance in common lambquarters please see: http://www.weedscience.org/Summary/USpeciesCountry.asp?lstWeedID=47&FmCommonName=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 common lambsquarters

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
Imazethapyr	Inhibition of acetolacetate synthase ALS (acetohydroxyacid synthase AHAS)
*Pursuit		4 - 6 ounces	Apply when the seedling alfalfa is in the second (2nd) trifoliate stage or larger and when the majority of the weeds are 1 to 3 inches. Apply to established alfalfa in the fall, in the spring to dormant or semi-dormant alfalfa or clover or between cuttings when there is less than 3 inches of regrowth.
Peas and Lentils
Pendimethalin	Microtubule assembly inhibition
*Prowl		4 pints	May be applied preplant incorporated for weed control in lentils and peas. Apply 60 days prior to planting up to immediately before planting. After application, rotary hoeing and shallow cultivation/tillage can be practiced without reducing weed control.
Grass Grown for Seed
Dicamba	Action like indole acetic acid (synthetic auxins)
*Clarity		8 - 24 ounces	Apply 8 - 16 fluid ounces on seedling grass after the crop reaches the 3 - 5 leaf stage. Apply up to 64 fluid ounces on well-established perennial grass. For best performance, apply when weeds are in the 2 - 4 leaf stage.
Potato
Pendimethalin	Microtubule assembly inhibition
*Prowl		1.5 - 3 pints	May be applied preemergence, preemergence incorporated, or early postemergence in potatoes. For postemergence, apply from crop emergence to the 6-inch stage of growth. DO NOT apply postemergence if potatoes are under stress from cold/wet or hot/dry conditions or crop injury may occur.
Small Grains
Carfentazone	Inhibition of acetyl CoA carboxylase (ACCase)
*Aim		0.5 - 1 ounce	Apply to small grains in all tillage systems from prior to planting up to jointing. For optimum control, apply to actively growing weeds that are up to 3 inches tall.
Post harvest, Fallow, Crop Stubble, Set Aside Acres
2,4-D	Action like indole acetic acid (synthetic auxins)
*Weedmaster		1 - 2 pints	Apply 1 pint when weeds are less than 6 inches tall and up to two pints when weeds are 6-20 inches tall. Apply as a broadcast or spot treatment to emerged and actively growing weeds after crop harvest (postharvest) and before a killing frost or in the fallow cropland or crop stubble the following spring or summer.

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 images please visit IPM Bugwood. http://www.ipmimages.org/search/action.cfm?q=common%20lambsquarter&Start=1&results=29