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Sharlene E. Sing

Research Entomologist

1648 South 7th Avenue, MSU Campus
Bozeman, MT 59717-2780
Contact Sharlene E. Sing

Current Research

I am involved in a range of collaborative studies with the overall objective of assessing and improving the efficacy and safety of classical weed biological control. One of my ongoing studies to further understand shortfalls in realized biological control of exotic toadflax will determine if toadflax biocontrol agents exhibit differential responses to yellow x Dalmatian toadflax hybrids vs. either of the parental toadflax species. The recently confirmed hybridization of these exotic weeds under field conditions potentially affects agents both behaviorally (in terms of host location and acceptance) and biologically (in terms of reproductive success). I am developing a host plant test list and participating in host selectivity testing with members of the North American Toadflax Consortium to identify and gain approval for the release of one or more new yellow toadflax biocontrol agents. Much of my research is undertaken to parameterize comparative ecological risk assessments for selecting optimally safe and effective invasive weed management strategies. I am also involved in long-term monitoring projects, including ecological and biocontrol studies on saltcedar, and evaluating the potential for integrating herbicide treatments and biological control of Dalmation toadflax on prescribed burn treated rangeland. New studies will focus on potential effects of climate change on weed biocontrol efficacy, identifying and evaluating biocontrol agents for Russian olive and oxeye daisy, and surveying and evaluating the ecological impacts of aquatic weeds to assess their potential as classical biological control targets.

Research Interests

Insect-plant interactions influencing and influenced by invasive species is the common theme running through my research.

Past Research

Classical weed biological control can be a cost-effective, sustainable and ecologically sound way to manage exotic invasive weeds. Unqualified weed biocontrol success stories are, however, altogether too rare. Developing, using and teaching methods for quantitatively evaluating the impact of biocontrol treatments will increase the documentation of successful releases when it does occur, and will satisfy currently unmet planning needs. Post-release monitoring is ethically critical to ensuring accountable management of public lands and resources; monitoring is truly the only way to detect negative outcomes such as treatment failures and shortfalls, and nontarget impacts. Coordinating and participating in the search for and testing of new weed biocontrol agents based on stakeholder needs will increase weed biocontrol implementation. Basic research focused on insect-plant interactions will continue to improve the safety of this management tool, and identify biological and ecological impediments when control shortfalls occur.

Why This Research is Important

1. Co-investigator on a collaborative project confirming naturally-occuring hybridization of yellow and Dalmatian toadflax; many ongoing and planned studies have built on this discovery. 2. Ecological risk assessment: collaborator on a number of studies that will be used for evaluating risks associated with invasive weeds and management approaches for those weeds. 3. Co-author of several technology transfer publications on the management or biological control of specific weeds: yellow toadflax, Dalmatian toadflax, houndstongue, tansy ragwort, and saltcedar.


  • Dalhousie University, Halifax, NS, B.A., English, 1984
  • McGill University, Montreal, QC, M.Sc., Natural Resource Sciences -Entomology, 1997
  • Montana State University, Bozeman, MT, Ph.D., Land Resources and Environmental Sciences (Agroecology), 2002
  • Featured Publications


    Venette, Robert C.; Gordon, Doria R.; Juzwik, Jennifer; Koch, Frank H.; Liebhold, Andrew M.; Peterson, Robert K. D.; Sing, Sharlene E.; Yemshanov, Denys, 2021. Early Intervention Strategies for Invasive Species Management: Connections Between Risk Assessment, Prevention Efforts, Eradication, and Other Rapid Responses
    Poland, Therese M.; Juzwik, Jennifer; Rowley, Allen; Huebner, Cynthia D.; Kilgo, John C.; Lopez, Vanessa M.; Olson, Deanna H.; Pearson, Dean E.; Progar, Robert; Rabaglia, Robert; Rothlisberger, John D.; Runyon, Justin B.; Sing, Sharlene E., 2021. Management of Landscapes for Established Invasive Species
    Gaskin, John F.; Espeland, Erin; Johnson, Casey D.; Larson, Diane L.; Mangold, Jane M.; McGee, Rachel A.; Milner, Chuck; Paudel, Shishir; Pearson, Dean E.; Perkins, Lora B.; Prosser, Chadley W.; Runyon, Justin B.; Sing, Sharlene E.; Sylvain, Zachary A.; Symstad, Amy J.; Tekiela, Daniel R., 2021. Managing invasive plants on Great Plains grasslands: A discussion of current challenges
    Liebhold, Andrew M.; Campbell, Faith T.; Gordon, Doria R.; Guo, Qinfeng; Havill, Nathan; Kinder, Bradley; MacKenzie, Richard; Lance, David R.; Pearson, Dean E.; Sing, Sharlene E.; Warziniack, Travis; Venette, Robert C.; Yemshanov, Denys, 2021. The Role of International Cooperation in Invasive Species Research
    Gaffke, Alexander M.; Sing, Sharlene E.; Dudley, Tom L.; Bean, Daniel W.; Russak, Justin A.; Mafra-Neto, Agenor; Grieco, Paul A.; Peterson, Robert K. D.; Weaver, David K., 2018. Semiochemicals to enhance herbivory by Diorhabda carinulata aggregations in saltcedar (Tamarix spp.) infestations
    Sing, Sharlene E.; De Clerck-Floate, Rosemarie; Hansen, Richard W.; Pearce, Hal; Randall, Carol Bell; Tosevski, Ivo; Ward, Sarah M., 2016. Biology and biological control of Dalmatian and yellow toadflax
    Matonis, Megan S.; Sing, Sharlene E.; Ward, Sarah; Turner, Marie F. S.; Weaver, David; Tosevski, Ivo; Gassmann, Andre; Bouchard, Patrice, 2014. Science You Can Use Bulletin (SYCU) - Toadflax stem miners and gallers: The original weed whackers
    Sing, Sharlene E.; Weaver, D. K.; Ward, S. M.; Milan, J.; Jorgensen, C. L.; Progar, R. A.; Gassmann, A.; Tooevski, I., 2013. Hybrid weeds! Agent biotypes!: Montana's ever-evolving toadflax biological control soap opera
    Wu, Yun; Johnson, Tracy; Sing, Sharlene E.; Raghu, S.; Wheeler, Greg; Pratt, Paul; Warner, Keith; Center, Ted; Goolsby, John; Reardon, Richard, 2013. Proceedings of the XIII International Symposium on Biological Control of Weeds; September 11-16, 2011; Waikoloa, Hawaii, USA
    Delaney, K.; Espeland, E.; Norton, A.; Sing, Sharlene E.; Keever, K.; Baker, J. L.; Cristofaro, M.; Jashenko, R.; Gaskin, J.; Schaffner, U., 2013. Russian olive - a suitable target for classical biological control in North America? In: Wu, Yun; Johnson, Tracy; Sing, Sharlene; Raghu, S.; Wheeler, Greg; Pratt, Paul; Warner, Keith; Center, Ted; Goolsby, John; Reardon, Richard, eds
    Andreas, J.; Wax, T.; Coombs, E.; Gaskin, J.; Markin, G.; Sing, Sharlene E., 2013. The Scotch Broom gall mite: Accidental introduction to classical biological control agent?
    Schat, Marjolein; Sing, Sharlene E.; Peterson, Robert K. D.; Menalled, Fabian D.; Weaver, David K., 2011. Growth inhibition of Dalmatian toadflax, Linaria dalmatica (L.) Miller, in response to herbivory by the biological control agent Mecinus janthinus Germar
    Sherman, J. D.; Weaver, D. K.; Hofland, M. L.; Sing, Sharlene E.; Buteler, M.; Lanning, S. P.; Naruoka, Y.; Crutcher, F.; Blake, N. K.; Martin, J. M.; Lamb, P. F.; Carlson, G. R.; Talbert, L. E., 2010. Identification of novel QTL for sawfly resistance in wheat
    Sing, Sharlene E.; Weaver, D. K.; Nowierski, R. M.; Markin, G. P., 2008. Long-term field evaluation of Mecinus janthinus releases against Dalmatian toadflax in Montana (USA)
    Dinkins, Courtney L. Pariera; Brumfield, Sue K.; Peterson, Robert K. D.; Grey, William E.; Sing, Sharlene E., 2007. Dalmatian toadflax (Linaria dalmatica): New host for cucumber mosaic virus
    Sing, Sharlene E.; Peterson, Robert K. D.; Maxwell, Bruce D., 2007. Invasive species management: Ensuring the 'cure' is not worse than the condition
    Wilson, Linda M.; Sing, Sharlene E.; Piper, Gary L.; Hansen, Richard W.; De Clerck-Floate, Rosemarie; MacKinnon, Daniel K.; Randall, Carol Bell, 2005. Biology and biological control of Dalmatian and yellow toadflax
    Weaver, David K.; Nansen, Christian; Runyon, Justin B.; Sing, Sharlene E.; Morrill, Wendell L., 2005. Spatial distributions of Cephus cinctus Norton (Hymenoptera: Cephidae) and its braconid parasitoids in Montana wheat fields
    Nansen, Christian; Weaver, David K.; Sing, Sharlene E.; Runyon, Justin B.; Morrill, Wendell L.; Grieshop, Matthew J.; Shannon, Courtney L.; Johnson, Megan L., 2005. Within-field spatial distribution of Cephus cinctus (Hymenoptera: Cephidae) larvae in Montana wheat fields
    Weaver, David K.; Wells, Carl D.; Dunkel, Florence V.; Bertsch, Wolfgang; Sing, Sharlene E.; Sriharan, Shobha, 1994. Insecticidal activity of floral, foliar, and root extracts of Tagetes minuta (Asterales: Asteraceae) against adult mexican bean weevils (Coleoptera: Bruchidae)
    Beetles crawling out of a white bucket into a tree.
    Saltcedar (Tamarix spp.), an aggressively invasive Eurasian tree, is a dominant and widespread woody riparian species in the southwestern U.S. Biocontrol of saltcedar with the leaf beetle Diorhabda carinulata can be made more effective with semiochemicals (smells). 
    A collection of diorhabda carinulata (which are brown-ish-orange and green insects) on a saltcedar plant
    Saltcedar (Tamarix spp.) refers to the complex of exotic invasive shrubs and trees (four species and their hybrids) now considered the third most prevalent woody riparian taxonomic group in the western United States. Defoliation by large multivoltine populations of the Northern tamarisk beetle Diorhabda carinulata has successfully reduced extensive saltcedar infestations in the southwestern United States. Behavioral manipulation of insects with semiochemicals such as aggregation pheromones can be used to intensify herbivory, even in the Northern Rockies where beetle population densities are inherently low, to the extent that the target weed species is negatively affected at a population level.
    Yellow toadflax (Linaria vulgaris).
    Two closely related invasive Linaria species, Dalmatian toadflax (Linaria Dalmatica) and yellow toadflax (Linaria vulgaris), have successfully invaded a broad range of ecosystems throughout most of continental North America. The management challenge imposed by the landscape scale of many toadflax infestations, particularly in the West, is further complicated by hybridization between these two weeds. Herbicide and biological control treatments for invasive Linaria are highly species-specific, necessitating the development of a molecular diagnostic tool to accurately confirm when cryptic hybridization has spontaneously occurred in the field, and habitat suitability modeling to predict areas most vulnerable to hybrid invasion.
    Alex Gaffke (front) and Diane Johnson (back) measuring Dalmatian toadflax density and heights on a biocontrol site transect, July 2013.
    The impacts of typical weed treatments on both the target weed(s) and non-target plant species that occur in large scale, chronic weed infestations are seldom quantitatively assessed or compared. Further, advantages or disadvantages of making high density ‘inundative’ biocontrol releases to counteract high levels of overwintering mortality affecting agent establishment and increase are seldom documented. Impacts of inundative biocontrol on Dalmatian toadflax abundance, non-target plant diversity, forage quality and quantity, and wildlife habitat quality will be assessed and compared to the impacts on the same resources either treated with aerial applied herbicides or left untreated.  
    Dalmatian toadflax is an aggressive invader of western rangelands. Photo by: Steve Dewey, Utah State University,
    Rocky Mountain Research Station scientists are investigating how climate change, namely elevated levels of CO2, might impact invasive species and classical biological control of weeds. A mechanistic approach to understanding how climate change may impact interactions between invasive plants and their biocontrol agents is essential for realistically addressing management needs under likely future field conditions.
    Optimizing classical biological control through the deployment of environmentally resilient agents may provide a sustainable, cost-effective and selective management option for large scale infestations of fire adapted weeds. Ongoing research is exploring the efficacy of a candidate agent, the stem mining weevil Mecinus heydenii, for biocontrol for invasive toadflax.
    Rocky Mountain Research Station scientists are investigating how climate change, namely elevated levels of CO2, might impact invasive species and classical biological control of weeds.