HPIPM:Bursage

Taxonomy

Domain	Eukarya
Kingdom	Plantae
Phylum	Magnoliophyta
Class	Magnoliopsida
Superorder	Asteranae
Order	Asterales
Family	Asteraceae
Subfamily	Asteroideae
Tribe	Heliantheae
Genus	Ambrosia

Scientific Name

Ambrosia tomentosa

Common Name

skeletonleaf bursage

Bursage (Ambrosia tomentosa)

Compiled by Melissa Graves and Marjolein Schat, Montana State University from the following sources:

http://www.oneplan.org/Crop/noxWeeds/nxWeed29.shtml

http://plants.usda.gov/java/profile?symbol=AMTO3

http://wisplants.uwsp.edu/scripts/detail.asp?SpCode=AMBTOM

http://www.uiweb.uidaho.edu/weeds/FRA/Skeletonleaf%20Bursage/Skeletonleaf%20Bursage.htm

Identification and Life Cycle

Bursage (Ambrosia tomentosa) is a perennial in the sunflower family (Asteraceae). Bursage is also known by other common names including skeletonleaf bursage, bur ragweed, and skeletonleaf bur ragweed. Bursage grows up to 3 feet tall. Leaves are alternate, up to 5 inches long, and very deeply lobed with coarsely toothed margins. The lobes are reduced in size from leaf base to tip. The upper leaf surface is greenish-gray and may have rough hairs; the lower surface is white with short, dense hairs. Flower heads are 1/4 inch wide and are produced from June through August. Each flower head contains inconspicuous yellow flowers that are either male or female (not both). Fruits are 2-seeded, light brown burs with up to 10 short spines. The plant has extensive horizontal roots.

Habitats

Bursage occurs from the desert Southwest to Wisconsin and Illinois, and tends to be found on poorly drained disturbed sites. It grows in cultivated fields, pastures, prairies, and waste areas.

Impacts

Bursage is a serious cropland weed. Throughout its range, bursage is also weedy in meadows, pastures, waste places, dry rangeland and plains. It is also unpalatable to livestock and produces pollen which aggravates allergies for those who are sensitive to ragweed pollen.

Biology and Ecology

Bursage is a long-lived perennial that reproduces by seeds and adventitious shoots from creeping roots. Flowering occurs from July through September. Seeds mature in September and October. Root fragments left by cultivation and shoots from lateral roots can produce dense clonal populations. It grows in low moist areas and can tolerate flooding for long periods. Bursage competition is especially severe in field depressions where irrigation or rainwater accumulates periodically. Established bursage emerges earlier in the growing season than associated crops, making it competetive, capturing light, moisture, and nutrients. Throughout its range, bursage is also weedy in meadows, pastures, waste places, dry rangeland and plains.

Biological Control

There are no biological control agents available for bursage.

Mechanical and Cultural Control

Mowing does not kill bursage and may stimulate additional shoot growth from root buds. Mowing may delay or reduce seed production. Repeated, persistent cultivation may deplete root reserves. Cultivation that delays shoot emergence, such as moldboard plowing, reduces the effectiveness of foliar applied herbicides because late-emerging shoots escape treatment.

Chemical Control

There are a number of chemical control options for bursage.

Examples of herbicides that can be used to manage bursage

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

Due to constantly changing labels, laws and regulations, the sponsors of this web site assume no liability for the suggested use of any chemicals noted in the management section. Contact your local pest management personnel for current information on labeled pesticides that can be used for the intended plant disease, insect pest or weed.

References

For more information and images please visit IPM Bugwood: http://www.ipmimages.org/search/action.cfm?q=skeletonleaf%20bursage