HPIPM:Dandelion

Taxonomy

Domain	Eukarya
Kingdom	Plantae
Phylum	Magnoliophyta
Class	Magnoliopsida
Superorder	Asteranae
Order	Asterales
Family	Asteraceae
Subfamily	Cichorioideae
Tribe	Cichorieae
Genus	Taraxacum

Scientific Name

Taraxacum officinale

Common Name

dandelion

Dandelion (Taraxacum officinale)

Compiled by Mary Rumph, Montana State University, Powder River County Extension, and Marjolein Schat, Montana State University from the following sources:

http://www.oardc.ohio-state.edu/weedguide/singlerecord.asp?id=950

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7469.html

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

http://128.104.239.6/uw_weeds/extension/articles/dandelion.htm

Identification and Life Cycle

Common dandelion (Taraxacum officinale) is a perennial in the sunflower family (Asteraceae). Dandelion has several common names including bitterwort, blow-ball, cankerwort, clockflower, common dandelion, Irish daisy, lion's tooth, piss-in-bed, pissinlit, priest's crown, puffball, swine's snout, telltime, and yellow gowan. The species has a deep, thick, branched taproot that exudes a milky juice if cut. Seed leaves (cotyledons) are pale, dull, yellowish-green, oval, and have smooth edges. Young leaves form a basal rosette and are oval to oblong with long hollow leaf stalks (petioles). Stems are erect, 2 to 12 inches tall, hollow, leafless, filled with milky juice, and terminate in a single flower head. Leaves are basal, bright green, thin, hairless, between 3 to 10 inches long, and jagged around the edges with lobes or teeth of various sizes and shapes. The terminal lobe is usually largest and lobes become smaller and more deeply divided toward the leaf base. Leaves are alternate (1 leaf per node), which is difficult to distinguish because stems are so compressed that nodes are generally at or below the soil surface. The leaf base tapers into a hollow, short petiole. Mature leaves exude a milky juice when cut or broken. The bright yellow, 1- to 2-inch-wide flowers form at the tips of long, hollow, flower stems. Flowers mature into fluffy white seed heads. The single-seeded fruits are brownish, narrow, about 3/16 inch long, and tapering to a slender beak that is 2 to 3 times as long as the seed. At the top of the beak are soft, white, bristly hairs (pappus).

Habitats

It is common in lawns, pastures, roadsides, and waste places. The species requires moist soil and sunlight in order to establish and thrive.

Impacts

The pappus on the seed frequently clogs up tractor radiators, and roots of dandelion are attractive to gophers. Dandelion is also a weed in irrigated pastures and alfalfa, and is rapidly becoming a troublesome weed in agronomic fields under reduced tillage regimes.

Biology and Ecology

Reproduction is by wind-blown seeds and regeneration from root fragments. Flowers form mostly in April and May, but flowers have been known to appear as early as February and as late as June. In some locations, secondary flowering occurs in autumn. Plants generally remain vegetative and do not initiate flowering until a satisfactory number of leaves form. Therefore, plants growing in tall grass without ample moisture and sunlight will usually not flower and may not survive. Total sunlight received determines leaf shape; plants growing in full sun have deeply-toothed, thick, green leaves compared with shade leaves that are slightly-toothed, thin, and pale. Estimates of the number of seeds produced per plant each year range from 3,000 to 23,000.

Biological Control

There are no biological control agents available for dandelion.

Mechanical and Cultural Control

Small infestations can be managed by digging or pulling dandelion plant, however, If the entire root is not removed, it can regenerate and grow into a mature plant either later in the season or next season. In one study, spring tillage reduced residual dandelion biomass by roughly 50%, yet did not reduce dandelion density.

Chemical Control

There are several chemical control options available for dandelion. 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 dandelion

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
Metribuzin	Photosynthesis inhibitor (Photosystem II)
*Sencor		1 - 3 pounds	Do not apply after growth begins in the spring or before growth ceases in the fall. Do not apply to alfalfa during the first growing season after seeding. Do not graze or harvest within 28 days after application. Apply when weeds are less than 2 inches tall or before weed foliage is 2 inches in diameter
Grass Grown for Seed
Dicamba	Action like indole acetic acid (synthetic auxins)
*Clarity		18 - 64 ounces	Apply 8 - 16 fluid ounces per treated acre 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 and rosettes are less than 2" across.
Barley
Dicamba	Action like indole acetic acid (synthetic auxins)
*Clarity		2 - 4 ounces	Apply 2 - 4 fluid ounces to fall-seeded barley prior to the jointing stage. Apply 2 - 3 fluid ounces before spring-seeded barley exceeds the 4-leaf stage.
Oats
Dicamba	Action like indole acetic acid (synthetic auxins)
*Clarity		2 - 4 ounces	Apply to fall-seeded oat prior to the jointing stage. Apply before spring-seeded oat exceeds the 5-leaf stage.
Wheat
Dicamba	Action like indole acetic acid (synthetic auxins)
*Clarity		2 - 4 ounces	See label for specific fall seeded programs. Otherwise, apply before fall seeded wheat reaches the jointing stage. Early season applications to spring seeded wheat must be made before wheat exceeds the 6-leaf stage.
Small Grains
Clopyralid	Action like indole acetic acid (synthetic auxins)
*Stinger		0.25 - 0.3 pints	Apply when the crop is from the 3-leaf stage up to the early boot stage. Do not harvest hay from treated fields.

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=dandelion&Start=1&results=123