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Combined Herbivory by Targeted Sheep Grazing and Biological Control Insects to Suppress Spotted Knapweed (Centaurea stoebe)

Published online by Cambridge University Press:  20 January 2017

Jeffrey C. Mosley*
Affiliation:
Department of Animal and Range Sciences, Montana State University, Bozeman, MT 59717
Rachel A. Frost
Affiliation:
Department of Animal and Range Sciences, Montana State University, Bozeman, MT 59717
Brent L. Roeder
Affiliation:
Montana State University Extension, P.O. Box 130, Choteau, MT 59422
Tracy K. Mosley
Affiliation:
Montana State University Extension, 119 S. 3rd St., Livingston, MT 59047
Gerald Marks
Affiliation:
Montana State University Extension, 2825 Santa Fe Court, Missoula, MT
*
Corresponding author's E-mail: jmosley@montana.edu

Abstract

The use of biological control insects is a promising option for suppressing spotted knapweed, a nonindigenous perennial forb that infests more than 3 million hectares of North American rangeland. Efficacy increases when spotted knapweed is attacked by more than one phytophagous insect; however, combined herbivory by biological control insects has not achieved widespread suppression of spotted knapweed in North America. Here we expand the concept of combined herbivory beyond two or more species of biological control insects to include a vertebrate herbivore, specifically targeted grazing by domestic sheep. Our experiment on foothill rangeland in northwestern Montana evaluated spotted knapweed response to three treatments: (1) biological control insects only, (2) biological control insects + targeted sheep grazing applied in late July (spotted knapweed in late bud–early flower stage), and (3) biological control insects + targeted sheep grazing applied in mid-August (spotted knapweed in full-flower stage). We combined targeted sheep grazing with herbivory by three species of biological control insects: knapweed flower weevil, knapweed root weevil, and sulfur knapweed root moth. Treatments were applied during four consecutive years (2009 to 2012). Spotted knapweed fitness was suppressed more where targeted sheep grazing and biological control insects were combined vs. areas treated with biological control insects alone. Combined herbivory was effective when targeted sheep grazing was applied during either late July or mid-August, but July grazing was more effective. Spotted knapweed produced 96 to 99% fewer viable seeds in sheep-grazed areas. After 4 yr of treatment, total spotted knapweed plant density (seedlings, juvenile, and adult plants) was 86% less in July-grazed areas and 61% less in August-grazed areas than in areas treated with biological control insects alone. Combined herbivory by targeted sheep grazing and biological control insects reduced adult plant density and prevented compensatory recruitment of spotted knapweed, but treatment with biological control insects alone did not.

Type
Research Article
Copyright
Copyright © Weed Science Society of America 

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References

Literature Cited

Benzel, KT, Brewer, TK, Mosley, JC (2009) Defoliation timing effects on spotted knapweed seed production and viability. Rangeland Ecol Manag 62:550556 CrossRefGoogle Scholar
Bucher, RF (1984) The potential cost of spotted knapweed to Montana range users. Bozeman, MT: Montana State University Cooperative Extension Service Bulletin 1316. 18 pGoogle Scholar
Callaway, RM, DeLuca, TH, Belliveau, WM (1999) Biological-control herbivores may increase competitive ability of the noxious weed Centaurea maculosa . Ecology 80:11961201 Google Scholar
Collins, AR, Müller-Schärer, H (2012) Influence of plant phenostage and ploidy level on oviposition and feeding of two specialist herbivores of spotted knapweed, Centaurea stoebe. Biol Control 60:148153 CrossRefGoogle Scholar
Duncan, CA (2005) Spotted knapweed, Centaurea stoebe L. ssp. Micranthos (Gugler) Hayek. Pages 5168 in Duncan, CA, Clark, JK, eds. Invasive Plants of Range and Wildlands and their Environmental, Economic, and Societal Impacts. Lawrence, KS: Weed Science Society of America Google Scholar
Eichberg, C, Storm, C, Schwabe, A (2005) Epizoochorous and post-dispersal processes in a rare plant species: Jurinea cyanoides (L.) Rchb. (Asteraceae). Flora 200:477489 Google Scholar
Eriksson, O, Ehrlen, J (1992) Seed and microsite limitation of recruitment in plant populations. Oecologia 91:360364 Google Scholar
Frost, RA, Mosley, JC (2012) Sulfur cinquefoil (Potentilla recta) response to defoliation on foothill rangeland. Invasive Plant Sci Manag 5:408416 CrossRefGoogle Scholar
Gayton, D, Miller, V (2012) Impact of biological control on two knapweed species in British Columbia. J Ecosyst Manag 13:114 Google Scholar
Harrod, RJ, Taylor, RJ (1995) Reproduction and pollination biology of Centaurea and Acroptilon species, with emphasis on C. diffusa . Northwest Sci 69:97105 Google Scholar
Henderson, SL, Mosley, TK, Mosley, JC, Kott, RW (2012) Spotted knapweed utilization by sequential cattle and sheep grazing. Rangeland Ecol Manag 65:286291 CrossRefGoogle Scholar
Hirsch, SA, Leitch, JA (1996) The impact of knapweed on Montana's economy. Fargo, ND: North Dakota State University Agricultural Experiment Station, Agricultural Economics Report 355. 43 pGoogle Scholar
Jacobs, J, Sing, SE, Martin, JM (2006) Influence of herbivory and competition on invasive weed fitness: observed effects of Cyphocleonus achates (Coleoptera: Curculionidae) and grass-seeding treatments on spotted knapweed performance. Environ Entomol 35:15901596 Google Scholar
Knochel, DG, Flagg, C, Seastedt, TR (2010a) Effects of plant competition, seed predation, and nutrient limitation on seedling survivorship of spotted knapweed (Centaurea stoebe ). Biol Invasions 12:37713784 Google Scholar
Knochel, DG, Monson, ND, Seastedt, TR (2010b) Additive effects of aboveground and belowground herbivores on the dominance of spotted knapweed (Centaurea stoebe ). Oecologia 164:701712 CrossRefGoogle ScholarPubMed
Knochel, DG, Seastedt, TR (2010) Reconciling contradictory findings of herbivore impacts on the growth and reproduction of spotted knapweed (Centaurea stoebe ). Ecol Appl 20:19031927 Google Scholar
Lacey, JR, Marlow, CB, Lane, JR (1989) Influence of spotted knapweed (Centaurea maculosa) on surface water runoff and sediment yield. Weed Technol 3:627631 CrossRefGoogle Scholar
Lee-Campbell, K, ed (1999) Best management practices for grazing Montana. Helena, MT: Montana Department of Natural Resources and Conservation. 29 pGoogle Scholar
Lejeune, KD, Suding, KN, Sturgis, S, Scott, A, Seastedt, TR (2005) Biological control insect use of fertilized and unfertilized diffuse knapweed in a Colorado grassland. Environ Entomol 34:225234 CrossRefGoogle Scholar
Maines, A, Knochel, D, Seastedt, T (2013a) Biological control and precipitation effects on spotted knapweed (Centaurea stoebe): empirical and modeling results. Ecosphere 4:114 Google Scholar
Maines, AP, Knochel, DG, Seastedt, TR (2013b) Factors affecting spotted knapweed (Centaurea stoebe) seedling survival rates. Invasive Plant Sci Manag 6:568576 Google Scholar
Mueggler, WF, Stewart, WL (1980) Grassland and shrubland habitat types of western Montana. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station, General Technical Report INT-66. Pages 154 pGoogle Scholar
Müller-Schärer, H (1991) The impact of root herbivory as a function of plant density and competition: survival, growth, and fecundity of Centaurea maculosa in field plots. J Appl Ecol 28:759776 Google Scholar
Müller-Schärer, H, Schroeder, D (1993) The biological control of Centaurea spp. in North America: do insects solve the problem? Pestic Sci 37:343353 CrossRefGoogle Scholar
Nathan, R, Muller-Landau, HC (2000) Spatial patterns of seed dispersal, their determinants and consequences for recruitment. Trends Ecol Evol 15:278285 Google Scholar
Newingham, BA, Callaway, RM, BassiriRad, H (2007) Allocating nitrogen away from an herbivore: a novel compensatory response to root herbivory. Oecologia 153:913920 Google Scholar
Olson, B, Launchbaugh, K (2006) Managing herbaceous broadleaf weeds with targeted grazing. Pages 5867 in Launchbaugh, K, Walker, J, Daines, R, eds. Targeted Grazing: A Natural Approach to Vegetation Management and Landscape Enhancement. Centennial, CO American Sheep Industry Association Google Scholar
Olson, BE, Wallander, RT (2001) Sheep grazing spotted knapweed and Idaho fescue. J Range Manag 54:2530 Google Scholar
Olson, BE, Wallander, RT, Lacey, JR (1997) Effects of sheep grazing on a spotted knapweed-infested Idaho fescue community. J Range Manag 50:386390 Google Scholar
Ortega, YK, Pearson, DE (2011) Long-term effects of weed control with picloram along a gradient of spotted knapweed invasion. Rangeland Ecol Manag 64:6777 Google Scholar
Ortega, YK, Pearson, DE, Waller, LP, Sturdevant, NJ, Maron, JL (2012) Population-level compensation impedes biological control of an invasive forb and indirect release of a native grass. Ecology 93:783792 CrossRefGoogle ScholarPubMed
Otway, SJ, Hector, A, Hector, JH (2005) Resource dilution effects on specialist herbivores in a grassland biodiversity experiment. J Anim Ecol 74:234240 Google Scholar
Pearson, DE, Callaway, RM (2006) Biological control agents elevate hantavirus by subsidizing mice. Ecol Lett 9:442449 Google Scholar
Pearson, DE, Fletcher, RJ Jr (2008) Mitigating exotic impacts: restoring deer mouse populations elevated by an exotic food subsidy. Ecol Appl 18:14891500 Google Scholar
Rice, PM, Toney, JC, Bedunah, DJ, Carlson, CE (1997) Elk winter forage enhancement by herbicide control of spotted knapweed. Wildl Soc B. 25:627633 Google Scholar
Ridenour, WM, Vivanco, JM, Feng, Y, Horiuchi, J, Callaway, RM (2008) No evidence for trade-offs: Centaurea plants from America are better competitors and defenders. Ecol Monogr 78:369386 Google Scholar
Rinella, MJ, Jacobs, JS, Sheley, RL, Borkowski, JJ (2001) Spotted knapweed response to season and frequency of mowing. J Range Manag 54:5256 Google Scholar
Seastedt, TR, Knochel, DG, Garmoe, M, Shoskoy, SA (2007) Interactions and effects of multiple biological control insects on diffuse and spotted knapweed in the Front Range of Colorado. Biol Control 42:345354 Google Scholar
Smith, L, Story, JM (2003) Plant size preference of Agapeta zoegana L. (Lepidoptera: Tortricidae), a root-feeding biological control agent of spotted knapweed. Biol Control 26:270278 CrossRefGoogle Scholar
Sneva, F, Britton, CM (1983) Adjusting and forecasting herbage yields in the Intermountain big sagebrush region of the steppe province. Corvallis, OR Oregon State University Agricultural Experiment Station Bulletin 659. 61 pGoogle Scholar
Sneva, FA, Hyder, DN (1962) Estimating herbage production on semiarid ranges in the Intermountain region. J Range Manag 15:8893 Google Scholar
Steel, RGD, Torrie, JH (1980) Principles and Procedures of Statistics: A Biometrical Approach. 2nd ed. New York McGraw-Hill. 633 pGoogle Scholar
Story, JM (2004a) Agapeta zoegana . Pages 207209 in Coombs, EM, Clark, JK, Piper, GL, Cofrancesco, AF Jreds. Biological Control of Invasive Plants in the United States. Corvallis, OR Oregon State University Press Google Scholar
Story, JM (2004b) Cyphocleonus achates . Pages 212213 in Coombs, EM, Clark, JK, Piper, GL, Cofrancesco, AF Jreds. Biological Control of Invasive Plants in the United States. Corvallis, OR Oregon State University Press Google Scholar
Story, JM, Callan, NW, Corn, JG, White, LJ (2006) Decline of spotted knapweed density at two sites in western Montana with large populations of the introduced root weevil, Cyphocleonus achates (Fahraeus). Biol Control 38:227232 Google Scholar
Story, JM, Coombs, EM (2004a) Larinus minutus . Pages 214216 in Coombs, EM, Clark, JK, Piper, GL, Cofrancesco, AF Jreds. Biological Control of Invasive Plants in the United States. Corvallis, OR Oregon State University Press Google Scholar
Story, JM, Coombs, EM (2004b) Larinus obtusus . Pages Pages 216217 in Coombs, EM, Clark, JK, Piper, GL, Cofrancesco, AF Jreds. Biological Control of Invasive Plants in the United States. Corvallis, OR Oregon State University Press Google Scholar
Story, JM, Smith, L, Corn, JG, White, LJ (2008) Influence of seed-head attacking biological control agents on spotted knapweed reproductive potential in western Montana over a 30-year period. Environ Entomol 37:510519 Google Scholar
Story, JM, White, LJ, Good, WR (1996) Propagation of Cyphocleonus achates (Fahraeus) (Coleoptera: Curculionidae) for biological control of spotted knapweed: procedures and cost. Biol Control 7:167171 Google Scholar
Surber, LMM, Rude, ME, Roeder, BL, Mosley, TK, Grove, AV, Walker, JW, Kott, RW (2011) Percent spotted knapweed (Centaurea stoebe) in the diets of grazing sheep. Invasive Plant Sci Manag 4:95101 Google Scholar
Taylor, JE, Lacey, J (1999) Monitoring Montana rangeland. Bozeman, MT: Montana State University Extension Service Bulletin 369. 22 pGoogle Scholar
Thrift, BD, Mosley, JC, Brewer, TK, Roeder, BL, Olson, BE, Kott, RW (2008) Prescribed sheep grazing to suppress spotted knapweed on foothill rangeland. Rangeland Ecol Manag 61:1825 Google Scholar
Tyser, RW, Key, CH (1988) Spotted knapweed in natural area fescue grasslands: an ecological assessment. Northwest Sci 62:151159 Google Scholar
[USDA-NRCS] U.S. Department of Agriculture–Natural Resources Conservation Service (2009) Droughty Steep Ecological Site Description, Northern Rocky Mountains. Bozeman, MT, USA: Montana Technical Guide, Section II. 26 pGoogle Scholar
[USDA-NRCS] U.S. Department of Agriculture–Natural Resources Conservation Service (2014) Web Soil Survey: Lake County Area, Montana, BigArm Cobbly Loam. http:/websoilsurvey.nrcs.usda.gov/. Accessed January 7, 2014Google Scholar
Vallentine, JF (2001) Grazing Management. 2nd ed. San Diego, CA Academic Press. 659 pGoogle Scholar
Watson, AK, Renney, AJ (1974) The biology of Canadian weeds. 6. Centaurea diffusa and C. maculosa . Can J Plant Sci 54:687701 Google Scholar
Wessels-de Wit, S, Schwabe, A (2010) The fate of sheep-dispersed seeds: plant species emergence and spatial patterns. Flora 205:656665 Google Scholar
Wilson, LM, Randall, CB (2005) Biology and biological control of knapweed. 3rd ed. Morgantown, WV: U.S. Department of Agriculture–Forest Service, Forest Health Technology Enterprise Team, FHTET-2001-07. 99 pGoogle Scholar
Wooley, SC, Smith, B, King, C, Seastedt, TR, Knochel, DG (2011) The lesser of two weevils: physiological responses of spotted knapweed (Centaurea stoebe) to above- and belowground herbivory by Larinus minutus and Cyphocleonus acates . Biocontrol Sci Technol 21:153170 Google Scholar
[WRCC] Western Regional Climate Center (2014) Period of record monthly climate summary, Polson Kerr Dam, Montana. http://www.wrcc.dri.edu. Accessed January 7, 2014Google Scholar