1. YELLOW STARTHISTLE NRES 641 Presented by Bignon Elsa INVASIVE PLANT

2. Introduction

3. Outline  1-General characteristics  2-Biology and characteristics that makes Yellow starthistle a good invader  3-Impacts  4-Management  5-Conclusion

4.  1-General characteristics  A-Taxonomy  B-Identification, description  C-Origin and habitat:

5.  1-General characteristics A- Taxonomy  Group: Dicotyledonous  Order: Asterales Family: Asteraceae Genus: Centaurea Species: Centaurea solstitialis L.AsteralesAsteraceaeCentaurea  SYNONYMS Yellow starthistle (YST) : Golden starthistle, yellow cockspur, St. Barnaby's thistle, Cottontip thistle.

6.  1-General characteristics B-Identification, description Yellow starthistle (YST) ( DiTomaso, 2007 ):  Gray-green to blue-green plant  Deep and vigorous taproot.  Yellow flowers with spines adjoining the base.  heights varying from 6 inches to 5 feet  rigid stems covered with a cottony wool  Basal leaves are 2 to 3 inches long and deeply lobed.

7. 1-General characteristics C-Origin and habitat:  Origin of yellow starthistle: Eurasia. It is native to Balkan-Asia Minor, the Middle East and south-central Europe (Maddox, 1981).  introduction into USA (1849) via South America as a seed contamination in alfalfa seed (Gerlach et al. 1998 ).  Now YST is found in 41 states and in 5 western national parks - Death Valley National Park, Glen Canyon National Recreation Area, Redwood National Park, Sequoia and Kings Canyon National Parks, and Yosemite National Park. (Murphy, 2005)  In California, the plant infests between 10 and 15 million acres (DiTomaso, 2007).  1-General characteristics C- Origin and habitat: Absent present Distribution of Yellow starthistle. Source:USDA website

8.  found typically in:  full sunlight  Deep well-drained soils, (annual rainfall 10-60 inches)  common in rangelands, pastures, hay fields, orchards, vineyards, waterways, roadsides, and even forests and other non-crop areas or in disturbed areas such as roadsides. (Zimmerman et al., 2001)  1-General characteristics C- Origin and habitat (cont.):

9.  2- Biology and characteristics that make Yellow starthistle a good invader  A- Seed production and germination  B-Growth  C-Reproduction and flowering

10.  2- Biology and characteristics that makes Yellow starthistle a good invader A- Seed production and germination  Winter annual plant, germinates in early spring  Only can reproduce by seed  prolific seed producer 35 to over 80 achenes per seedhead. ( Benefield et al. 2001, Maddox 1981).  A plant can produce up to 150,000 seeds (Zimmerman et al., 2001)

11. Phenological development of yellow starthistle flowers from pre-bloom spiny stage to petal abscission. Seed viability occurred at late senescence stage. Source: DiTomaso 1996  Time period from flower initiation to the development of mature viable seed is only 8 days. ( DiTomaso, 2006 )

12.  Two types of seed inYST seedheads (DiTomaso, 1996) :  Dark and lack a pappus.  Majority: brown with a bristly pappus ring at the apex  2- Biology and characteristics that makes Yellow starthistle a good invader A- Seed production and germination (Cont.) yellow starthistle seeds Source: www.cdfa.ca.gov/centaurea-solstitialis.htmwww.cdfa.ca.gov/centaurea-solstitialis.htm

13.  Good light + good soil moisture + good temperature (50 °F to 70 °F) = nearly 100% seeds can germinate (DiTomasso et al, 2006)  90% of YST achenes are germinable 1 week after seed dispersal (Benefield et al. 2001).  YST achenes depleted by 80% after 1 year  By 3 years only 3.9% still viable (Joley et al. 1992)  2- Biology and characteristics that makes Yellow starthistle a good invader A- Seed production and germination (Cont.) Decline in seedbank. When the introduction of new seeds is prevented, the yellow starthistle seedbank declines almost completely over three years. Source: Joley et al. 1992 Dynamics of yellow starthistle (Centaurea solstitialis) achenes in field and laboratory

14.  2- Biology and characteristics that makes Yellow starthistle a good invader B- Growth  After germination, YST will dedicate most of its energy to root growth, leaf expansion, stem development and flowers (Roche et al 1994).  Roots can extend more than 3 feet into the underground.  Rapid germination + deep root growth are traits that allow it to compete very well against shallow- rooted native plants during the hot and dry summer months. ( DiTomasso, 1996) Root growth. Roots of yellow starthistle plants grow deep rapidly, even in the rosette stage. Source: DiTomasso et al. 2006 24 days after planting 31 days 44 days 52 days 38 days

15.  YST begins flowering in late May and continues through September  It has very low levels of self-fertilization (Harrod and Taylor 1995, Maddox et al. 1996).  a large amount of cross- fertilization insures a high degree of genetic variability within populations ( Dittomaso et al 2006).  Importance of Honeybees:  Honeybees maintain high pollination rates.  Contribution may be >50% of the seed set. ( Barthel et al. 2001).   honey bees and yellow starthistle may act as invasive mutualists. 2- Biology and characteristics that makes Yellow starthistle a good invader C- Reproduction and flowering A honey bee foraging at a flower head of yellow star-thistle. Source: Haag.E, February 2009

16.  3-Impacts  A- Negative impacts Economic Toxicity to horse/ dangerous for livestock Roadside and recreational area Wildland Water consumption  B-Positive impacts Honey Food for ruminants

17.  YST : significant issue and considered one of the most serious rangeland, grassland, and wildland weeds in the western of the United States.  Infest grain harvested  decrease crop quality + value.  Significant direct costs to control YST on public lands (e.g costs of  materials  labor for treatments 3- Impacts A- Negative impacts  Economic In California 0.5 million acres are managed at about $25 per acre for a cost of about $12.5 million annually in management (DiTomaso et al. 2006).

18.  Horses eat YST: Chronic poison which causes neurological disorder of the brain: nigropallidal encephalomalacia or “chewing disease.”  No treatments known  Most of the time the animal dies  LD : 2.3 to 2.6 kg YST/ 100 kg of body weight per day (Cheeke and Shull,1985).  Only horses are affected by YST. 3- Impacts A- Negative impacts  Toxicity to horse/ Dangerous for livestock  All grazing animals can have eye damages due to the plant’s long, sharp spines (Haag, 2009) YST sharp spines Source/ az.gov/invasivespecies/tenmostunwanted.html

19. 3- Impacts A- Negative impacts  Roadside and recreational area  YST is the most important roadside weed problem in much of central and northern California. (Maddox et al.1985),  Spread along roadside with contaminated soil, vehicles and equipments (DiTomaso et al 2006)

20.  YST can limit or impede human access if the area is infested. (trails and campgrounds, hunting areas, and recreational vehicle parks)  On certain military bases, YST can impact training exercises and can impair the use of equipment (e.g., snagged parachutes, torn clothing)+ YST can cause mechanical injury to humans (particularly to the face) when the spines are encountered (Miller, 2003). 2- Impacts A- Negative impacts  Roadside and recreational area (cont)

21.  YST is directly responsible for transforming millions of acres of complex and diverse native ecosystems into marginal plant communities most of time dominated by a single species (Haag E, 2009, DiTomaso et al. 2006; Zimmerman et al., 2001).  YST affects fire frequency by changing fuel characteristics. This may impede the reestablishment of native species because the community cannot find the initial fire balance (DiTomaso et al.2006). 3- Impacts A- Negative impacts  Wildland

22.  YST affects soil moisture:  YST has caused losses of soil moisture resources on invaded sites of 15–25% of mean annual precipitation. (Gerlach, 2003)  Major consumer of ground­water, costs the state millions of dollars in lost water for wildlife, agriculture and municipal uses.  Based on a conservative estimate of YST coverage in the Sacramento River watershed: YST may cause an annual economic loss of $16 to $75 million in water conservation costs alone. Gerlach, (2003)  Because of its high water usage, YST threatens both human economic interests as well as native plant ecosystems. 3- Impacts A- Negative impacts  Water consumption

23.  The weed is regarded as an important honey plant and late-season food source for bees in California (Barthell et al. 2001).  YST has acceptable nutritional value as a component of a ruminant’s diet and leaves are highly digestible by ruminant during growing season. (Thomsen et al. 1989).  And YST is available to cattle at a time when most grasses and forbs are past and have poor nutritional value. (Haag, 2009)  But  YST nutritional value declines as the plants grows.  Pasture infested contain considerably less crude protein and total digestible nutrients compared to uninfested pastures (Barry, 1995). 3- Impacts A- Positif impacts  Honeybee and livestock food Yellows starthistle Honeybee. Source: http://ecx.images- amazon.com/images/I/41zWKE3SpzL._SL500_.jpg

24.  4- Management  A-Biopredation  B- Cultural Control  C- Chemical control  D-Integrated approach

25. 4- Management A- Biopredation  Biological control goal is to use natural enemies to control a target weed.Research began in the mid 1960s and continues today. (DiTomaso et al. 2006)  Five insects (natural enemies from Europe) :  three weevils (Bangasternus orientalis and Eustenopus villosus and larinus curtus)  and two flies (Urophora sirunaseva and Chaetorellia succinea).  They directly or indirectly reduce seed production by attacking the flower/seed head.  Advantages:  highly host-specific to the weed  do not attack commercially valuable crops or native plants.  Disadvantages:  only suppress about 50%, of YST seed production so,  they should not be considered as the exclusive method of control. ( DiTomaso et al. 2007)  Most recently the rust fungus Puccinia jaceae var. solstitialis was released in California. It was the first pathogen approved for biological control. It completes its entire life cycle on YST. But it has not yet demonstrated a strong record of persistence and regeneration. (Woods et al. 2010)

26. Chaetorellia succinea Source: californiaagriculture.ucanr.org/landingpage. Table 1 Comparaison of adult yellow starthistle weevils Source: www.invasive.org/weeds/starthistle/chapter2.htmlwww.invasive.org/weeds/starthistle/chapter2.html 4- Management A- Biopredation (cont)

27. 4-Management B- Cultural control  Mowing  Mowing early growth stages may results in increased light penetration and rapid regrowth of the weed.  Repeated mowing of plants too early in their life cycles (rosette or bolting stages) or when branches are below the mowing height will not prevent seed production, as flowers will develop below the mower cutting height.  Grazing  Sheep, goats, or cattle eat YST before spines form on the plant.  The plant’s crude protein concentration is variable but can be sufficient to meet the general maintenance requirements for most ruminants. ( DiTomaso et al. 2007)  Burning  good way to reduce yst if it is applied when flowers appear.  Burning for two or more consecutive years can help deplete the soil seedbank. Burning is also a good way to increase the recovery and density of perennial grasses. (DiTomaso et al. 2006)  These practices are capable of reducing YST populations, but without competition, it will often reestablish.

28.  Revegetation  Species choice is dependant of the intended use site. (e.g: resident vegetation such as perennial bunchgrasses or wildflowers may be advantageous along roadsides, abandoned pastures).  other methods (cultural, biological and chemical control) can be used simultaneously to reduce YST while encouraging other plant species.  In all instances, choose desirable species that are well adapted to the site and not likely to become invasive themselves. Species that grow well are the best competitors. ( DiTomaso et al. 2007) 4-Management B- Cultural control (cont.)

29. 4- Management C-Chemical control Postemergent herbicides  Aminopyralid and clopyralid : growth regulator herbicides.Use in non­crop areas. (They are postemergent and preemergent)  2,4-D (growth regulator)  acceptable control of YST if applied in the rosette growth stage.  Dicamba (growth regulator)  control YST at low rates in rosette stage(0.25 lb active ingredient/acre).  higher rates (0.5 to 0.75 lb active ingredient/acre) are needed if plants are larger. ( DiTomaso et al. 2007)

30.  Triclopyr (growth regulator)  is effective at controlling seedlings  but is not as effective on larger plants. More mature plants require higher concentration of active ingredient. It is foliar- absorbed and active on broadleaf species, but typically does not harm grasses. (DiTomaso et al. 2007)  Glyphosate (amino acid inhibitor).  It provides effective control of yellow starthistle at 1 lb active ingredient/acre.  But non selective and controls most plants, including grasses. ( DiTomaso et al. 2007) 4- Management C-Chemical control Postemergent herbicides (cont)

31.  Preemergent Herbicides  Chlorsulfuron and sulfometuron :registered for roadsides and other noncrop uses. Very effective when applied at 1 to 2 oz active ingredient/acre. ( DiTomaso et al. 2007). 4- Management C-Chemical control Preemergent herbicides

32. 4-Management D-Integrated approach  Combinations of prescribed burning + clopyralid = very efficient.  But: When using this method it is important that:  prescribed burn be conducted the first year (or possibly for 2 years) and then clopyralid be applied in the last year of the program.  Then, a control of YST after the last year of treatment can be accomplished by mowing, spot spraying, or hand-pulling. ( DiTomaso et al. 2007).

33. Conclusion  YST is an important invader in the West of the United States, particularly in California and in some parts of Nevada.  This successful invasion results from a  good adaptation to a favorable climate and  Biological characteristics that make it a good competitor  a lack of enemies in the land it invades.  The most important impact is certainly the water consumption which costs the state millions of dollars in lost water for wildlife, agriculture and municipal uses each year.  Many ways to control it, included both effective chemical methods and more biological methods (cultural control and biopredation). Both methods are effectives, but an integrated approach can be more efficient if it is well realized.

34. References :  Barthell, J.F., J.M. Randall, R.W. Thorp, and A.M. Wenner. 2001. Promotion of seed set in yellow star-thistle by honey bees: evidence of an invasive mutualism. Ecological Ap­plications 11(6):1870–1883.  Barry, S. 1995. Cattle fecal fax. University of California, Coop­erative Extension. October Report, Nov. 7, 1995.In DiTomaso J.M, Kyse.G. B, Pitcairn M. J. 2006. Yellow Starthistle Management Guide. Published by the California invasive Plant Council.  Benefield, C.B., J.M. DiTomaso, G.B. Kyser, and A. Tschohl. 2001. Reproductive biology of yellow starthistle (Centaurea solstitialis): Maximizing late season control. Weed Science 49:38-90.  Cheeke, P.R. and L.R. Shull. 1985. Other plant toxins and poisonous plants. Ch. 11. pp. 358-392. In: Natural Toxi­cants in Feeds and Poisonous Plants. The Avi Publ. Co., Westport, CT.In DiTomaso J.M, Kyse.G. B, Pitcairn M. J. 2006. Yellow Starthistle Management Guide. Published by the California invasive Plant Council.  Callihan, R.H., T.S. Prather and F.E. Northam. 1993. Longevity of yellow starthistle (Centaurea solstitialis) achenes in soil. Weed Technology.7:33-35.  DiTomaso J. M, Kyser G. B, Lanini W. T, Thomsen C. D, Prather T. S. (2007); YELLOW STARTHISTLE Integrated Pest Management for Home Gardeners and Landscape Professionals; Pest note; pp1-5  DiTomaso J.M, Kyse.G. B, Pitcairn M. J. 2006. Yellow Starthistle Management Guide. Published by the California invasive Plant Council. pp 1- 64  DiTomaso J.M. 1996.Yellow Starthistle: Biology and Life History; Weed Science Program, California Exotic Pest Plant Council.pp 1-4  Gerlach, J.D., A. Dyer, and K.J. Rice. 1998. Grassland and foothill woodland ecosystems of the Central Valley. Fre­montia 26:39-43. IN DiTomaso J.M, Kyse.G. B, Pitcairn M. J. 2006. Yellow Starthistle Management Guide. Published by the California invasive Plant Council. pp 1- 64  Gerlach, J.D. Jr. 2003. The impacts of serial land-use changes and biological invasions on soil water resources in Califor­nia, USA. Journal of Arid Environments 57(3): 365-379.  Haag E. February 2009. Yellow Starthistle, A three-year California Study suggests controlling the star thistle with timely grazing. Angus journal pp198-201.

35.  Harrod, R.J. and R.J. Taylor. 1995. Reproduction and pollina­tion biology of Centaurea and Acroptilon species, with emphasis on C. diffusa. Northwest Science 69(2):97-105.  Joley, D.B., D.M. Maddox, B.E. Mackey, S.E. Schoenig, and K.A. Casanave. 1997. Effect of light and temperature on germination of dimorphic achenes of Centaurea solstitia­lis in California. Canadian Journal of Botany 75(12):2131-2139.In DiTomaso J.M, Kyse.G. B, Pitcairn M. J. 2006. Yellow Starthistle Management Guide. Published by the California invasive Plant Council. pp 1-64  Joley, D.B., D.M. Maddox, D.M. Supkoff, and A. Mayfield. 1992. Dynamics of yellow starthistle (Centaurea solstitia­lis) achenes in field and laboratory. Weed Science 40:190-194.  Panter, K.E. 1991. Neurotoxicity of the knapweeds (Centaurea spp.) in horses. pp. 316-324. In DiTomaso J.M, Kyse.G. B, Pitcairn M. J. 2006. Yellow Starthistle Management Guide. Published by the California invasive Plant Council  Maddox, D.M. 1981. Introduction, phenology, and density of yellow starthistle in coastal, intercoastal, and central val­ley situations in California. ARR-W-20, pp. 1-33. USDA-ARS. In DiTomaso J.M, Kyse.G. B, Pitcairn M. J; (2006); Yellow Starthistle Management Guide. Published by the California invasive Plant Council. pp 1-64  Maddox, D.M., A. Mayfield, and N.H. Poritz. 1985. Distri­bution of yellow starthistle (Centaurea solstitialis) and Russian knapweed (Centaurea repens). Weed Science 33(3):315-327.  Maddox, D.M., D.B. Joley, D.M. Supkoff, and A. Mayfield. 1996. Pollination biology of yellow starthistle (Centau­rea solstitialis) in California. Canadian Journal of Botany 74:262-267.In DiTomaso J.M, Kyse.G. B, Pitcairn M. J; (2006); Yellow Starthistle Management Guide. Published by the California invasive Plant Council.  Miller, J.R. 2003. Integrated Management of Yellow Starthistle (Centaurea solstitialis) at Fort Hunter Liggett, Monterey County, California. M.S. thesis. University of California, Davis.In DiTomaso J.M, Kyse.G. B, Pitcairn M. J; (2006); Yellow Starthistle Management Guide. Published by the California invasive Plant Council.  Murphy.A; 2005. FACT SHEET: YELLOW STARTHISTLE. Plant Conservation Alliance®s Alien Plant Working Group:Alien Plant Invaders of Natural Areas.pp1-3  Woods D.M., O'Brien J.M., Kyser G.B., DiTomaso J.M. Effects of the rust Puccinia jaceae var. solstitialis on Centaurea solstitialis (yellow starthistle) growth and competition (2010) Biological Control, 52 (2), pp. 174-181.  Thomsen, C.D., W.A. Williams, M.R. George, W.B. McHen­ry, F.L. Bell, and R.S. Knight. 1989. Managing yellow starthistle on rangeland. California Agriculture 43(5):4-7.  Thomsen, C.D., W.A. Williams, M. Vayssieres, C.E. Turner, and W.T. Lanini. 1996. Yellow starthistle biology and control. Univ. Calif., Div. Agr. Nat. Res. Publication #21541. 19 pp.  WILSON L M., CYNTHIA JETTE, JOHN CONNETT, JOSEPH MCCAFFREY, (JULY 2003), Biology and biological control of yellow starthistle, 2 nd edition  Zimmerman J. R, Johnson W. S, Eiswerth M. E. 2001. Yellow Starthistle Control in Nevada An Integrated Approach to Invasive Weed Management; University of Nevada Reno. pp1-11