United States Department of Agriculture

Field Guide for Managing Dyer’s Woad in the Southwest

Forest Southwestern Service Region TP-R3-16-18 September 2014 Cover Photos Top: Steve Dewey, Utah State University, Bugwood.org Bottom left: Steve Dewey, Utah State University, Bugwood. org Bottom right: Steve Dewey, Utah State University, Bugwood.org

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual’s income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 720-2600 (voice and TTY). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, SW, Washington, DC 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TTY). USDA is an equal opportunity provider and employer.

Printed on recycled paper Dyer’s woad ( tinctoria L.) Mustard family ()

Dyer’s woad is listed as a noxious weed in both Arizona • Fruits are a primary distinguishing feature. Thin, flat and New Mexico. This field guide serves as the U.S. Forest pods are initially , turning black at maturity; the Service’s recommendations for management of dyer’s woad persistent, samara-like fruits hang from slender, short in forests, woodlands, and rangelands associated with its pedicels. Southwestern Region. The Southwestern Region covers • Reproduces via seed; each pod produces one seed. Arizona and New Mexico, which together have 11 national However, each produces an average of 300 to forests. The Region also includes four national grasslands 500 seeds; under certain conditions a single plant may located in northeastern New Mexico, western Oklahoma, produce 10,000 seeds. and the Texas panhandle. Ecology Description Impacts/threats Dyer’s woad develops dense, monotypic stands that crowd Dyer’s woad (synonyms: Asp-of-Jerusalem, glastum) is out native species. Established infestations reduce forage a member of the Mustard family and grows as a winter available for cattle and horses, degrade wildlife habitat, annual, biennial, or short-lived perennial. It is native to lower flora and fauna species diversity, and decrease land southeastern Russia and has historically been cultivated for value. Its dominant presence increases the potential for soil use as a . It is currently being studied for its anti- erosion. cancer properties and potential as a less toxic alternative to wood preservative and inkjet printer fluid. Dyer’s woad Location was accidentally introduced to the western United States This weed is common along roadsides and railway rights- as a contaminant in alfalfa seed during the early 1900s of-way; upon dry, rocky foothills and hillsides; within both and has since proliferated throughout the arid West. It has disturbed and undisturbed pastures and rangelands. It is been observed in Santa Fe and Sandoval Counties in New a serious problem especially in intermountain sagebrush Mexico and Coconino County in Arizona. communities in Utah, Nevada, Wyoming, Montana, and Growth Characteristics California. • Grows as a winter annual, biennial or short-lived Spread perennial depending on local Seed is easily dispersed by animals, human activity, and environmental conditions; 2 to 4 feet tall. water. Seed is spread long distances as a contaminant • Produces a taproot (30 inches long) and lateral roots in alfalfa hay or seed, and by adhering to surfaces and found mostly in the upper 12 inches of soil. undercarriages of vehicles and road maintenance equipment.

• Has fine haired, basal leaves in the rosette stage that Invasive Features are twice as long as they are wide with a pale mid- Dyer’s woad is an aggressive, dry-land invader due to its vein; grows an erect upright woody stem (20 to 35 prolific seed production, early emergence, and deep taproot. inches) during bolting. Initial invasion may occur in a disturbed area; however, it • Stems leaves are 1 to 4 inches long, grayish-green, can rapidly expand into undisturbed rangeland and wooded narrow, alternate, basally lobed; clasping stem. areas. Dyer’s woad produces a water-soluble chemical that • Yellow, 4-petalled flowers occur mostly in April to inhibits germination of other and can delay its own July in flat-topped bunches at branch tips. germination until favorable precipitation levels are available.

1 It grows rapidly between the rosette and flowering • Check hay, straw, and mulch for presence of weed stages (up to 4 inches per week) and can resprout from seed before using in areas where dyer’s woad is not adventitious buds at its crown. currently present; certified weed-free hay or pellets should be fed to horses used in back-country areas.

Management Table 1 summarizes some management options for Detecting dyer woad populations early and taking measures controlling dyer’s woad under various situations. Choice of to manage the plant soon after discovery is important for individual control method(s) for dyer’s woad depends on control. Due to copious seed production and seed bank the degree and density of infestation, current land use, and formation, large populations are difficult to eradicate once site conditions (accessibility, terrain, microclimate, other established. Continuous aggressive management measures flora and fauna present, etc.). Other important considerations are needed to keep populations under control. Small or include treatment effectiveness, overall cost, and the number isolated infestations on otherwise healthy sites should be of years needed to achieve control. More than one control given high priority for treatment, followed by treatment method may be needed for a particular site. of corridors with a high likelihood for spread, such as Physical Control roadsides and waterways. Regardless of the management Although labor intensive, physical methods that are approach, it must be recognized that dyer’s woad cannot consistently and repeatedly used can be effective at be effectively controlled within a single year or by using controlling dyer’s woad. By removing plants before seed only one method. Complete control will likely require 3 to set, seed production is reduced. Effectiveness of physical 10 years of repeated management methods. The following methods can be improved when combined with herbicide actions should be considered when planning an overall control. management approach: Manual Methods • Maintain healthy plant communities and encourage the presence of ground litter to help suppress Hand removal – Hand pulling, hoeing or grubbing at least germination of dyer’s woad seedlings. This may twice per year; once in May, just as flowers start to bloom involve using improved grazing management to and again 2 to 3 weeks later to eliminate any remaining prevent excessive grazing and reseeding areas with plants. Montana’s Dyer’s Woad Cooperative Project has desirable grasses and forbs after disturbance. used hand pulling to attain high levels of control and to eradicate dyer’s woad from 9 of 13 infested counties. If • Detect, report, and map known infestations. Keep flowers or seed pods are present, plant debris should be annual records of reported infestations. bagged and disposed of in a landfill to prevent germination • Eradicate new populations of dyer’s woad as early as and spread. At rosette and bolt stages, plants may be pulled possible. and left onsite. • Combine mechanical, cultural, biological, and Hand cutting coupled with spot spraying herbicide upon chemical methods for most effective dyer’s woad remaining basal leaves is another effective management control. method; it reduces seed production and addresses root • Implement a monitoring and followup treatment plan fragments. for missed plants and seedlings.

2 Table 1. Management options* Site Physical Methods Cultural Methods Biiological Methods Chemical Methods Roadsides, Repeatedly mow during Clean machinery following Use woad rust in For ground application, use fence lines, summer after bolting but activity in infested areas. combination with truck-mounted or tractor- or noncrop before seed set. herbicides (metsulfuron pulled spraying equipment. Train road crews to identify areas or chlorsulfuron are Hand pull or grub; or cut and report, infestations; map Wash under vehicle after compatible). stem, followed by herbicide reported populations. application to prevent on basal leaves. spread. Rangelands, Use early spring or late Use certified weed-free seed Use prescribed grazing For extensive and dense pastures, fall tillage where feasible; and hay. strategy with sheep or infestations, use ground or or riparian combine with herbicide. goats in combination with aerial broadcast spraying. Reseed with plants that are corridors herbicide control. Prescribed burning is not desirable and will compete. For sparse infestations, recommended due to limited Closely manage grazing to use backpack or hand-held information on effects. prevent overuse. sprayer.

Wilderness, Hand pull or grub beginning Educate the public to Consider introducing a Use backpack or hand-held other natural in May and repeating every identify and report biological control agent sprayers. areas, and/ 2 to 3 weeks. Remove as infestations. such as woad rust (see table Broadcast spraying by aerial or small much of the root as possible 3). After passing through or ground methods may be infestations or dig up and sever root at infested areas, in spect used on thicker stands, if least 2 inches below crown. and remove any seed from allowed. Bag and dispose of debris animals, clothing, and appropriately. vehicles. * Choice of a particular management option must be in compliance with existing regulations for land resource.

Mechanical Methods spring herbicide application is used, allow dyer’s woad to Mowing – Repeated mowing can reduce dyer’s woad germinate and form rosettes before spraying (see table 3). seed production in localized, accessible situations, such If machinery is used to manage dyer’s woad, the equipment as along roadsides or in agronomic settings. However, if should be cleaned to prevent movement of seeds or root done improperly, it is possible that mowing will increase fragments into uninfested areas. regrowth from the root crown. Consider repeated mowing Prescribed Fire (every 10 to 14 days) after plants have bolted, but before seed has set during the summer. Herbicide may be applied 2 Burning is not well studied as a management method for weeks before mowing. controlling dyer’s woad. Based on response to other methods which only remove top growth, dyer’s woad is likely to Tillage – Tillage can be effective against dyer’s woad rapidly regrow following a burn. Burning is acceptable as a but likely is feasible only in limited settings. Areas with means to dispose of plant debris. suitable terrain should be tilled twice per year: once in the spring before seed production and again in the fall Cultural Control to capture late germinating plants. It is preferable to use Early detection and plant removal are critical for preventing tillage in combination with a reseeding effort. Local dyer’s woad establishment. Land managers, the local conditions dictate when reseeding should be accomplished. public, and road crews should be educated as to how to Typically, desired grass and forb seed are planted in late identify nonnative noxious species so they can help report summer or early autumn in Arizona and New Mexico. If a all suspected infestations. Vehicles, humans, and livestock

3 should be discouraged from traveling through infested Agents used for biological control in southwestern states areas; and a program to check and remove seeds from should be adaptable to arid environments and local vehicles and livestock should be implemented to help conditions. Public, tribal, and private land managers stop dispersal. If possible, remotely monitor and develop may obtain biological control agents for release directly GPS-based maps of infested areas. Public involvement from local offices of the USDA Animal and Plant Health and collaborative programs may be considered to address Inspection Service (APHIS) when the agents are available. existing and future dyer’s woad populations. Other sources for biocontrol agents include private companies or locally developed insectaries. A permit must Biological Control be obtained from APHIS before biological control agents Grazing can be transported across state boundaries. Regulations and Goats and sheep both graze dyer’s woad. Sheep graze permit applications (PPQ Form 526 permit forms) pertaining dyer’s woad until mid-May but show preference for other to interstate shipment of biological control agents may be more desirable forage species after that. Goats willingly eat found at http://www.aphis.usda.gov/ppq/permits/. Although dyer’s woad regardless of growth stage and timing. In order biological control agents may be collected and released to significantly impact seed production and plant mortality, within a given state without a permit from APHIS, the dyer’s woad needs to be clipped to less than a 2-inch height state’s Department of Agriculture or Agricultural Extension toward the end of May. To attain this high utilization rate, Service should be consulted for any regulations relating to there is also a high potential for damaging desirable species. movement of these agents inside the state. Managers need to carefully evaluate if using an intensive Chemical Control grazing approach might outweigh the management benefit. Herbicides listed in table 3 can be an effective and Classical Biological Agents economical management tool, but always include monitoring The rust fungus, Puccina thlaspeos, is naturally occurring and a followup treatment plan when developing a strategy and targets dyer’s woad specifically by suppressing or for dyer’s woad control. Single herbicide applications rarely preventing seed formation. Complete seed destruction is provide complete control and, at a minimum, several years rare, and viable seed can still be produced by diseased are needed to attain long-term control. Dyer’s woad is most plants. Infected plants have a stunted growth appearance susceptible to metsulfuron (Escort) or chlorsulfuron (Telar) with curled, sickly leaves. The rust normally spreads applied alone or in combination with 2,4-D or dicamba (i.e., slowly but researchers have found that collected material Cimarron Plus or Cimarron Max). A nonionic surfactant containing the rust can be dried, ground, and mixed in a should be added to these spray mixtures as specified on the solution for spraying. For further information on biological herbicide label. These herbicides are most effective when control of dyer’s woad, see Jacobs and Pokorny (2007) in applied during the seedling to rosette stages up to bolting the “References and Further Information” section of this and flowering. Spraying during the early flower stage and field guide. before seed formation prevents viable seed production.

Table 2. Classical biological control agents Use/Considerations for Species Type of Agent Site of Attack/Impact Remarks Release Puccina Rust fungus Systemic for whole plant. Infects rosettes Apply inoculum in the spring. Completes its life thlaspeos the first year; significantly impacts flower Once established, the rust cycle on one host and seed production the second year; spreads on its own. (autoecious). self-replicating.

4 Table 3. Herbicide recommendations

Backpack Common Product Sprayer Chemical Product Example Time of Treatment Remarks Name (active Example1 Rate per Acre Application Using Product ingredient) (broadcast) Example2 Metsulfuron Escort XP 0.75–1 ounce 1% Rosette to Selective broadleaf herbicide; noninjurious bloom stage. to most perennial grasses; absorbed through foliage; inhibits cell division. Best as a postemergent; add 0.25% v/v nonionic surfactant. Chlorsulfuron Telar XP 1–3 ounces 0.7–2% Seedling to Semiselective; safe for labeled grasses; rosette. growth inhibitor; absorbed by foliage and roots; best applied during warm, moist season. Preemergent or postemergent; use 0.25% v/v nonacidic adjuvant for postemergent application. Imazapic Plateau 8–12 ounces 1–3% Rosette to Selective broadleaf herbicide; noninjurious bolting plants. to most perennial grasses; use higher rate at later life stages. 2,4-D 3 several 1.5–2 quarts 1–5% Seedling to Use higher rate upon sites with greater manufacturers rosette stage. dyer’s woad densities. In combination with a surfactant, may adversely impact woad rust.

Metsulfuron + tank mix 0.5 ounce 1% In spring; bud to Under dry, dusty conditions, addition of 2,4- 2,4-D amine 3 Escort + 3 pints early bloom. D can improve weed control. 2,4-D Addition of 2,4-D with a surfactant may impact woad rust. Chlorsulfuron + tank mix 1–3 ounces + 3 1% Same as above. Same as above. 2,4-D 3 pints 2,4-D 1 Trade names for products are provided for example purposes only, and other products with the same active ingredient(s) may be available. Individual product labels should be examined for specific information and appropriate use with dyer’s woad. 2 Herbicide/water ratio - As an example, a gallon of spray water with a 3 percent mixture is made by adding a sufficient volume of water to 4 ounces of liquid herbicide until a volume of 1 gallon is reached (4 oz ÷ 128 oz/gal = 0.03 or 3 percent). 3 2,4-D is a restricted use pesticide in New Mexico only. A certified applicator’s license is required for purchase and use.

Imazapic (Plateau) with methylated seed oil (MSO) will sprayers that are pulled or attached to a tractor or truck. also control dyer’s woad when applied to rosettes or bolting For sparse populations, one person or a small team can plants. Dyer’s woad tolerance to herbicide increases at spot spray dyer’s woad by wetting the foliage and stems later life stages; therefore, increased application rates are without dripping using an adjustable spray nozzle attached required. to a backpack or hand-held sprayer. Generally, a 1 percent solution of metsulfuron or 5 percent solution of 2,4-D is an Herbicides may be applied in several ways including effective rate for spot treatment. backpack, ATV or UTV sprayers, or conventional boom

5 For all herbicide applications, it is important to read the References and herbicide label carefully, as different products will have different requirements and restrictions. Label instructions Further Information and guidelines for mixing, application, and grazing Davison, J.C., E. Smith, and L.M. Wilson. 2007. Livestock restrictions following treatment should always be followed. Grazing Guidelines for Controlling Noxious Weeds Consult the registrant if you have questions or need further in the Western United States. A Western Region detail. Sustainable Agriculture, Research and Education Project. EB-06-05. Pp. 20–21. Available at http:// Typically, reseeding is not necessary after spraying dyer’s www.cnr.uidaho.edu/rx-grazing/Livestock_Graizng_ woad. Treatments with metsulfuron and chlorsulfuron will Guidelines%28Davison_et_al.%202007%29.pdf selectively control dyer’s woad and allow native grasses to (accessed July 2010) return naturally. When 2,4-D is used, early spring timing Duncan, K., K. McDaniel and M. Renz 2005. Chemical will reduce impact to nontarget plant species. Picloram and Weed and Brush Control for New Mexico Rangelands. dicamba, applied alone, have not been found effective in New Mexico State University College of Agriculture controlling dyer’s woad. and Cooperative Extension Service. Pp. 7. Available at http://aces.nmsu.edu/pubs/_circulars/CR_597.pdf Control Strategies (accessed July 2010) Because each treatment situation is unique, the strategy Encycloweedia Datasheets by California Department of adopted for dyer’s woad control must involve careful Food and Agriculture. Available at http://www.cdfa. planning and a long-term commitment to management ca.gov/phpps/ipc/weedinfo/isatis.htm (accessed July actions. A combination of strategies—as outlined in 2010) this guide—should always be considered as a long-term Invasive Plant Atlas of the United States. Available at http:// approach for dyer’s woad control. For example, physical www.invasive.org/weedus/index.html (accessed July or biological control methods used in combination with 2010) chemical control are effective options. Regardless of the strategy used, components of a program for successful Jacobs, J. and M. Pokorny. 2007. Ecology and Management dyer’s woad control should include: (1) public education of Dyer’s Woad (). USDA/NRCS and involvement, (2) periodically repeating treatments, Technical Note No. MT-10. Available (3) monitoring of treated areas, and (4) measures taken to at http://www.msuextension.org/ruralliving/Dream/ control missed plants and emerging seedlings. PDF/Weed/dyers_woad.pdf (accessed July 2010) Kedzie-Webb, S. R. Sheley and S. Dewey. 2000. Dyers Dyer’s woad has generally been ignored in the Southwest Woad: A Threat to Rangeland in Montana. Montana because it is not yet a widespread problem in this region. State University Extension Publication No. However, dyer’s woad offers an opportunity to be proactive MT199614. Available at http://www.co.yellowstone. in addressing this invasive weed in its early stages of mt.gov/extension/ag/pubs/mt9614.pdf (accessed July infestation. Success in keeping dyer’s woad from becoming 2010) a more extensive and expensive problem in this region will likely come from working collaboratively and in coordination with the public and other land managers.

6 McAdoo, J.K. and J. Carpenter. 2002. Woad Warriors West, N.E. and K.O. Farah. 1989. Effects of Clipping and Community Weed Awareness. University of Nevada- Sheep Grazing on Dyer’s Woad. Journal of Range Reno Cooperative Extension Publication 02-62. Management 42(1):5–10. Available at http://www.unce.unr.edu/publications/ Zouhar, Kris. 2009. Isatis tinctoria. In: Fire Effects files/nr/2002/FS0262.pdf (accessed July 2010) Information System (Online). U.S. Department of New Mexico State University. Weed Information. Available Agriculture, Forest Service, Rocky Mountain Research at: http://weeds.nmsu.edu/ (Accessed July 2010) Station, Fire Sciences Laboratory (Producer). Available at http://www.fs.fed.us/database/feis/ Pokorny, M.L. and J.M. Kruger-Mangold. 2007. Evaluating (accessed July 2010) Montana’s Dyer’s Woad (Isatis tinctoria) Cooperative Eradication Project. Weed Technology 21:262–269 Suggested Web Sites Available at http://www.weedcenter.org/inv_plant_ For information on invasive species: info/docs/MT-Dyers_woad.pdf (accessed July 2010) http://www.invasivespeciesinfo.gov/ USDA Forest Service. 2006. Weed of the Week: Dyer’s http://www.invasive.org/weedus/index.html woad (Isatis tinctoria L.) Available at http://www. For information about calibrating spray equipment: invasive.org/weedcd/pdfs/wow/dyers_woad.pdf (accessed July 2010) NMSU Cooperative Extension Service Guide A-613 Sprayer Calibration at http://aces.nmsu.edu/ USDA Plants Database. 2010. Available at http://plants. pubs/_a/A-613.pdf usda.gov/java/profile?symbol=ISTI (accessed July 2010) Herbicide labels online: http://www.cdms.net/LabelsMsds/LMDefault.aspx Washington State Noxious Weed Control Board. 1999. Dyer’s Woad: Written Findings. Available at http:// www.nwcb.wa.gov/weed_info/Written_findings/ Isatis_tinctoria.html (accessed July 2010)

7

For more information or other field guides, contact:

USDA Forest Service Southwestern Region Forest Health 333 Broadway Blvd., SE Albuquerque, NM 87102

Or visit: http://www.fs.usda.gov/main/r3/forest-grasslandhealth/invasivespecies

The use of trade or firm names in this publication is for reader information and does not imply endorsement by the U.S. Department of Agriculture of any product or service. It does not contain recommendations for their use, nor does it imply that the uses discussed here have been registered. All uses of pesticides must be registered by appropriate State and/or Federal agencies before they can be recommended.

CAUTION: Pesticides can be injurious to humans, domestic animals, desirable plants, and fish or other wildlife—if they are not handled or applied properly. Use all pesticides selectively and carefully. Follow recommended practices for the disposal of surplus pesticides and pesticide containers.