HPIPM:Common groundsel

Taxonomy

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

Scientific Name

Senecio vulgaris

Common Name

common groundsel

Common groundsel(Senecio vulgaris)

Author: Cheryl A. Wilen, University of California Statewide IPM Program

Identification and Life Cycle

Common groundsel (Senecio vulgaris) is an introduced winter annual in the sunflower family (Asteraceae). The first true leaves of seedlings have shallow teeth, may be purple on the underside, and are attached to the stem with a short petiole. Later developing leaves are more deeply lobed and are attached directly to the stem. Leaves alternate on the stem and are mostly hairless. In full sun, groundsel grows up to 2-feet tall with a shallow taproot and a secondary fibrous root system and is often branched. Under shaded conditions the mature plant will have a scraggly appearance with fewer and smaller leaves. Flowers generally form about 6 weeks from sprouting. Flower clusters are surrounded by green bracts with black tips. This characteristic black tip distinguishes common groundsel from other plants in the Asteraceae family. Flowers are bright yellow and when the seeds mature, the bracts fully open to reveal a ball of white-tufted seeds. These seeds are easily dislodged and carried by wind. Under good growth conditions the plant can produce numerous flowers. When growing in shade or other stressful conditions the plant may only produce a few flower heads.

Habitats

Although common groundsel grows best in moist fertile soil, it can grow in more trying environments such as along roadsides and other disturbed sites.

Impacts

Early emerging common groundsel plants can out-compete later emerging crop seedlings and reduce their growth. Common groundsel plants that emerge after the crop is established are not effective competitors and have less of an impact. The most harmful consequence of the weed is liver poisoning of livestock.

Biology and Ecology

Common groundsel can germinate over a wide range of temperatures and can tolerate cold temperatures. The primary blooming period is March to April, although plants can flower throughout the summer. Plants can produce seeds when only a few inches tall. Seeds do not require a dormant period before germination, and most seeds germinate within a year.

Management Approaches

Common groundsel is best controlled by eliminating the plant before it flowers. Since seeds can still mature even if the plant itself is killed, it is imperative to remove the plant from the area if there is any evidence of flowering. Seeds of common groundsel are not long-lived, usually remaining viable for about one year. Therefore, controlling this weed before flowering will have a great impact on the size of the next year's population.

Biological Control

The most promising method of biological control is the use of the rust fungus Puccinia lagenophorae. This fungus provided about 30% control in greenhouse tests. Research is being conducted to find ways to improve its efficacy. There are no insects that are effective for controlling common groundsel.

Mechanical and Cultural Control

Small infestations of common groundsel are easily controlled by hand removal or cutting the plants off at the taproot by hoeing. Monitoring the area on a regular basis and removing the weed throughout the growing season will greatly reduce the impact of the weed the next year. In larger areas, tilling of young plants is effective. Mowing can be effective if the blade is set as close to the ground as possible. Mulches are very effective for controlling common groundsel. Seedlings cannot push through a 3-inch deep layer of mulch. Blown in seeds cannot establish on mulch if the surface is allowed to dry out.

Chemical Control

Herbicides can effectively control common groundsel in cereal crops, but selective control in actively growing forage legumes is very difficult, and in alfalfa, herbicide applications are restricted to the dormant season.

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 groundsel

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		6 ounces	Apply post-emergence only to seedling or established alfalfa grown for forage, hay or seed. Apply after alfalfa has reached the second trifoliate stage and when common groundsel is less than 3 inches tall.
Small Grains
Clopyrald	Action like indole acetic acid (synthetic auxins)
*Stinger		0.25 - 0.33	Apply when grain crops are from 3 leaf stage to early boot stage and before weeds reach the 5 leaf stage.
Grass Grown for Seed
Glyphosate	Inhibition of EPSP synthase
*Roundup Original		24 - 32 ounces	Apply before weeds reach 10 inches in height.

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=Common%20Groundsel

For more information on common groundsel please see the University of California IPM Online guide for common groundsel. http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74130.html