HPIPM:Blue mustard

Taxonomy

Domain	Eukarya
Kingdom	Plantae
Phylum	Magnoliophyta
Class	Magnoliopsida
Superorder	Rosanae
Order	Brassicales
Family	Brassicaceae
Genus	Chorispora

Scientific Name

Chorispora tenella

Common Name

blue mustard

Blue mustard(Chorispora tenella)

Author: Drew Lyon, University of Nebraska Lincoln

Identification and Life Cycle

Blue mustard (Chorispora tenella) is an introduced annual weed in the mustard family (Brassicaceae). Flowers are bluish-purple to purple with four petals. Plants can reach 6 to 18 inches in height. Stems and leaves are sparsely to moderately covered with small, gland-tipped hairs. Seedlings have oval and somewhat glandular leaves. Leaves are lance-shaped with wavy or coarsely-toothed margins. Fruits (siliques) are long and slender and about 1 to 1 1/2 inches long. Seeds are smooth, round, about 1/16 of an inch in diameter, and red to brown in color. It has a stout taproot.

Habitats

Blue mustard occurs in dry disturbed sites such as waste places, pastures, and along roadsides and railroad right-of-ways. It is also a problem in winter annual crops such as winter wheat and perennial crops like alfalfa.

Impacts

Blue mustard can reduce crop yields. Dairy cattle grazing in infested pastures may produce off-flavor milk.

Biology and Ecology

Seeds germinate in late summer and fall, and the plant overwinters as a rosette. Bolting occurs in March. Blue mustard flowers in early April. Viable seeds can be produced 10 days after bloom. Plants reproduce only from seed.

Biological Control

There are no biological control agents available for blue mustard

Mechanical and Cultural Control

Changing crop rotation is suggested for heavily infested fields. Including a spring seeded crop such as corn, sorghum, soybean, oat, proso millet, or sunflower in the rotation to allow two years between winter wheat crops breaks the life cycle of blue mustard. This will reduce the blue mustard population in future winter wheat crops by depleting the soil seed bank. Tilling before plants produce flowers will reduce the amount of seed entering the soil seed bank.

Chemical Control

Herbicides are most effective when applied before blue mustard stems elongate. 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 blue mustard

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
Glyphosate	Group 9: Inhibitor of EPSP synthase
*Helosate Plus		12 ounces	In dormant alfalfa, apply before weed reaches 6 inches tall.
*Roundup Original Max		11 ounces	In dormant alfalfa: Before weed reaches 6 inches tall.
Diuron,hexazinone	Groups 7 & 5: Inhibitors of photosynthesis
*Velpar Alfamax		1.5 - 3 pounds	Apply pre-emergence or early post emergence
Clearfield® Wheat
Imazamox	Group 2: Inhibitors of acetolactate synthase (ALS)
*Beyond		4 ounces	Apply before blue mustard reaches 6 inches in height
Wheat, Barley, and Triticale
2,4-D	Group 4: Synthetic auxins
*2,4-D ester		1/2 - 3/4 pt for the 4 lb/gallon product	Spring, 4 tillers to joint stage and before mustard bolts.
Metsulfuron, thifensulfuron, tribenuron	Group 2: Inhibitors of acetolactate synthase (ALS)
*Ally Extra SG		0.3 - 0.4 ounces	Fall, after wheat is in the 2-leaf stage.
Fallow
2,4-D	Group 4: Synthetic auxins
*2,4-D ester		3/4 pt for the 4 lb/gallon product	Fall or spring before bolting.
Pasture, Rangeland, and CRP areas
Chlorsulfuron, metsulfuron	Group 2: Inhibitors of acetolactate synthase (ALS)
*Cimarron Plus		0.125 ounces	Treat when weeds are less than 4 inches tall
Non-crop sites and around Aquatic Sites
Glyphosate	Group 9: Inhibitor of EPSP synthase
*Rodeo		1.5 pints	Apply before blue mustard reaches 6 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=blue%20mustard

For more information on blue mustard please see University of Nebraska-Lincoln Extension, Institute of Agriculture and Natural Resources publication G1272: Blue Mustard Control. http://www.ianrpubs.unl.edu/epublic/live/g1272/build/g1272.pdf