Phone: (217) 333-9654


About Us


Research Projects

Research Team





USDA / Agricultural Research Service



Adam S. Davis

B.A., Yale University, Biology

M.S., University of Maine, Ecology and Environmental Science

Ph.D. Iowa State University, Crop Production and Physiology



Research Interests


The goal of my research program is to make weed management in field crops more dependable, more profitable for farmers, and less likely to have negative impacts on environmental quality and non-target organisms. To this end, I am investigating ways of spreading weed management opportunities throughout the weed life cycle, rather than focusing solely on herbicide control of weed seedlings. One category of new tactics I am working on is techniques for managing the weed seedbank. Both empirical studies and simulation models suggest that reducing weed seed persistence in the soil seedbank should have a major impact on weed populations. Seedbank management tactics currently under investigation in my lab include conservation biocontrol for increased seed decay and fatal germination by soil microbes and increased seed predation by invertebrates and small vertebrates, direct reduction of inputs to the seedbank through modifications of harvest machinery and suppression of seedling recruitment from the seedbank through cover crop management practices. Plant demography serves as a unifying theme in my studies of weed ecology and management. In this approach, empirical and modeling work complement each other in an iterative process: experiments provide insight into how control tactics affect weed life stages and provide input for simulation models of management effects on weed population dynamics; model output then helps to focus the objectives of further empirical studies. Together, these tools help advance the understanding and implementation of ecological weed management.


Curriculum vitae




DeDecker, J.J., J.B. Masiunas, A. S. Davis, and C. G. Flint. 2014. Weed management practice selection among Midwest U.S. organic growers. Weed Science. 62:520-531.


West, N. M., D. P. Matlaga, A. S. Davis. 2014. Quantifying targets to manage invasion risk: light gradients dominate the early regeneration niche of naturalized and pre-commercial Miscanthus populations. Biological Invasions. 16:1991-2001.


Schutte, B. R., A. S. Davis. 2014. Do common waterhemp (Amaranthus rudis) seedling emergence patterns meet criteria for herbicide resistance simulation modeling? Weed Technology.28: 408-417.


Tiansawat, P., A. S. Davis, M. Berhow, P. C. Zalamea, J. W. Dalling. 2014. Investment in seed physical defence is associated with species' light requirement for regeneration and seed persistence: evidence from Macaranga species in Borneo. PLOS ONE. 9 (6): e99691. DOI: 10.1371/journal.pone.0099691.


Schutte, B. J., A. S. Davis, S. A. Peinado Jr., N. Klypina and J. Ashigh. 2014. Seed coat thickness data clarifies seed size-seed persistence tradeoffs in Abutilon theophrasti (Malvaceae). Seed Science Research 24: 119-131.


Lowrance, R and A. S. Davis. 2014. Environmental sustainability of cellulosic energy cropping systems. Pp. 299-313 in (D. Karlen ed.) Cellulosic energy cropping systems, John Wiley and Sons, Inc: New York, NY.


Smith, R.G., A. S. Davis, N. Jordan, L.W. Atwood, A. B. Daly, A. S. Grandy, M. C. Hunter, R. T. Koide, D. A. Mortensen, P. Ewing, D. Kane, M. Li, Y. Lou, S. S. Snapp, K. A. Spokas, A. C. Yannarell. 2014. Structural equation modeling facilitates transdisciplinary research on agriculture and climate change. Crop Science. 54:1-9.


Schutte, B.J., B. J. Tomasek, A. S. Davis, L. Andersson, D. L. Benoit, A. Cirujeda, J. Dekker, F. Forcella, J. L. Gonzalez-Andujar, F. Graziana, A. J. Murdoch, P. Neve, I. A. Rasmussen, B. Sera, J. Salonen, F. Tei, K. S. Torresen. 2014. A framework for understanding stimulation of weed seedling emergence by soil disturbance. Weed Research. DOI: 10.1111/wre.12054.

Lou, Y., S. Clay, A. S. Davis, A. Dille, J. Felix, H. Ramirez, C. Sprague and T. Yannarell. 2014. An affinity-effect relationship for microbial communities in plant-soil feedback loops. Microbial Ecology. DOI: 10.1007/s00248-013-0349-2.

Liebman, M, Z. Miller, C. Williams, P. Westerman, P. Dixon, A. Heggenstaller, A. S. Davis, F. Menalled, D. Sundberg. 2014. Fates of Setaria faberi and Abutilon theophrasti seeds in three crop rotation systems. Weed Research. DOI: 10.1111/wre.12069.

Schutte, B., A. S. Davis, S. Wortman, J. Lindquist. 2013. Maternal environment effects on phenolic defenses in Abutilon theophrasti seeds. Am J. Plant Sciences. 4: 1127-1133.


Davis, A. S., S. Clay, J. Cardina, A. Dille, F. Forcella, C. Sprague. 2013. Seed burial physical environment explains departures from regional hydrothermal model of giant ragweed seedling emergence in U.S. Midwest. Weed Science. 61: 415-421.


Davis, A. S., E. C. Taylor, E. R. Haramoto and K. A. Renner. 2013. Annual Postdispersal Weed Seed Predation in Contrasting Field Environments. Weed Sci. 61: 296–302.


Matlaga, D. P. and A. S. Davis. 2013. Minimizing invasive potential of Miscanthus × giganteus grown for bioenergy: identifying demographic thresholds for population growth and spread. J. Appl. Ecol. 50: 479-487.


Davis, A.S., J. D. Hill, A. M. Johanns, C. A. Chase, M. Liebman. 2012. Increasing cropping system diversity balances productivity, profitability and environmental health. PLoS One. 7(10): e47149. doi:10.1371/journal.pone.0047149


Evans, J., A. S. Davis, S. Raghu, A. Raghavendran, D. Landis, S. Schemske. 2012. The importance of space, time and stochasticity to the demography and management of Alliaria petiolata. Ecol. Appl. 22: 1497-1511.


Matlaga, D. P., L. D. Quinn, R. Stewart and A. S. Davis. 2012. Light response of native and introduced Miscanthus sinensis seedlings. Invasive Plant Science and Management. 5:363-374.


Liu, J., A. S. Davis and P. Tranel. 2012. Pollen biology and dispersal dynamics in waterhemp (Amaranthus tuberculatus). Weed Science. 60:416-422.


Wortman, S. E., A. S. Davis, B. J. Schutte, J. L. Lindquist, J. Cardina, J. Felix, C. L. Sprague, J. A. Dille, A.H.M. Ramirez, G. Reicks, and S. A. Clay. 2012. Local conditions, not regional gradients, drive demographic variation of Ambrosia trifida and Helianthus annuus across northern U.S. maize belt. Weed Science 60:440-450.


A. J. Bicksler, J. Masiunas and A. S. Davis. 2012. Canada thistle (Cirsium arvense) suppression by sudangrass interference and defoliation. Weed Science. 60: 260-266.


Davis, A. S. and E. A. Ainsworth. 2012. Weed interference with field-grown soybean (Glycine max) decreases under elevated [CO2] in a FACE experiment. Weed Research. 52: 277-285.


Matlaga, D., B. J. Schutte and A. S. Davis. 2012. Age-dependent population dynamics of the bioenergy crop Miscanthus x giganteus in Illinois. Invasive Plant Science and Management. 5: 238-248.


Davis, A. S., D. Daedlow, B. Schutte and P. R. Westerman. 2011. Temporal scaling of episodic point estimates of weed seed predation to long-term predation rates. Methods Ecol. Evol. 2: 682-892.


Evans, J. A. and A. S. Davis. 2011. Implications of demographic models for invasive plant management: a comment on "Complex population dynamics and control of the invasive biennial Alliaria petiolata (garlic mustard). Ecol. Appl. 21: 608-613.


Thinglum, K, C. Riggins, A. S. Davis, K. Bradley, K. Al-Khatib and P. Tranel. 2011. Wide distribution of the waterhemp (Amaranthus tuberculatus) D-G210 PPX2 mutation, which confers resistance to PPO-inhibiting herbicides. Weed Sci. 59: 22-27.


Wortman, S., A. S. Davis, B. Schutte and J. Lindquist. 2011. Integrating management of soil nitrogen and weeds. Weed Sci. 59: 162-170.


Quinn, L. D., D. P. Matlaga, A. S. Davis and R. Stewart. 2011. Evaluating the influence of wind speed on caryopsis dispersal of Miscanthus sinensis and Miscanthus x. giganteus. J. Invasive Plant Sci. Mgt. 4: 142-150.


Raghu, S., J.L. Spencer, A.S. Davis, R. Wiedenmann. 2011. Ecological context for the careful consideration/evaluation of biofuels: challenges and potential solutions. Curr. Opin. Environ. Sust. 3:15-23.


Davis, A. S. and D. A. Landis. 2011. Invasive species in agriculture. pp. 7-11 In M. Rejmanek and D. Simberloff (Eds.) The Encyclopedia of Exotic Invasive Species. UC Press: Berkeley, CA.


Schutte, B. J., E. R. Haramoto and A. S. Davis. 2010. Methods for Optimizing Seed Mortality Experiments. Weed Technol. 24: 599-606.


Schutte, B. J., A. Hager and A. S. Davis. 2010. Repeat applications of glyphosate on custom-applied, glyphosate-resistant soybeans in Illinois: how many and why? Weed Technol. 24: 590-598.


Dalling, J. W., A. S. Davis, B. J. Schutte and A. E. Arnold. 2010. Seed survival in soil: interacting effects of predation, dormancy and the soil microbial community. J. Ecol. doi: 10.1111/j.1365-2745.2010.01739


Davis, A. S. and S. Raghu. 2010. Weighing abiotic and biotic factors in weed seed predation. Weed Res. 40: 402-412.


Davis, A. S. 2010. Cover-crop roller–crimper contributes to weed management in no-till soybean. Weed Sci. 58: 300-309.


Schutte, B. J., J. Liu, A. S. Davis, S. K. Harrison and E. E. Regnier. 2010. Environmental factors that influence a mutualism between the earthworm Lumbricus terrestris L. and the annual weed Ambrosia trifida L. Agric. Ecosyst. Envir. 138: 197-205. [PDF available upon request.]


Davis, A. S., R. D. Cousens, J. Hill, R. N. Mack, D. Simberloff and S. Raghu. 2010. Screening bioenergy feedstock crops to mitigate invasion risk. Front. Ecol. Environ. doi:10.1890/090030.


Lankau, R., G. Spyreas, V. Nuzzo and A. S. Davis. 2009. Evolutionary limits ameliorate the negative impact of an invasive plant. Proceedings of the National Academy of Sciences USA. 106: 15362-15367.

Liebman, M. and A. S. Davis. 2009. Managing weeds in organic farming systems: an ecological approach. ed. Pp. 173-196 In Organic farming: The ecological system. C. Francis Ed. Madison, WI: American Society of Agronomy. Reprint available upon request.


Y. F. So, M. M. Williams II, J. K. Pataky, and A. S. Davis. 2009. Principal Canopy Factors of Sweet Corn and Relationships to Competitive Ability with Wild-Proso Millet (Panicum miliaceum). Weed Science. 57:296-303.

 Davis, A. S., J. C. Hall, M. Jasieniuk, M. A. Locke, E. C. Luschei, D. A. Mortensen, D. E. Riechers, R. G. Smith, T. M. Sterling, and J. H. Westwood. 2009. Weed science research and funding: a call to action. Weed Science. 57:442-448.


B. F. Tracy and A. S. Davis. 2009. Weed biomass and species composition as affected by an integrated crop-livestock system. Crop Science. 49:1523-1530.

 M. M. Williams II, A. S. Davis, T. L. Rabaey, and C. Boerboom. 2009. Linkages among agronomic, environmental and weed management characteristics in North American sweet corn. Field Crops Research. 113:161-169.


Davis, A. S. and E. C. Luschei. 2009. Living boundaries: tracking weed seed movement with non-dormant seed. Weed Science. 57:163-168.

B. J. Schutte, A. S. Davis , K. A. Renner and J. Cardina. 2008. Maternal and Burial Environment Effects on Seed Mortality of Velvetleaf ( Abutilon theophrasti ) and Giant Foxtail ( Setaria faberi ). Weed Science. 56:834-840.


A. S. Davis , D. Brainard and E. R. Gallandt. 2008. Introduction to the Symposium on Invasive Plant Species and the new bioeconomy. Weed Science. 56:866.

 Davis, A. S., B. J. Schutte, J. Iannuzzi and K. A. Renner. 2008. Chemical and physical defense of weed seeds in relation to soil seedbank persistence. Weed Sci. 56: 676-684.


Sweeney, A. E., K. A. Renner, C. Laboski and A. Davis. 2008. Effect of fertilizer nitrogen on weed emergence and growth. Weed Sci. 56: 714-721.

Davis, A. S. 2008. Weed seed pools concurrent with corn and soybean harvest in Illinois . Weed Sci. 56: 503-508.


Liebman, M., L. R. Gibson, D. N. Sundberg, A. H. Heggenstaller, P. R. Westerman, C. A. Chase, R. G. Hartzler, F. D. Menalled, A. S. Davis and P. M. Dixon. 2008. Agronomic and Economic Performance Characteristics of Conventional and Low-External-Input Cropping Systems in the Central Corn Belt. Agron. J. 100: 600-610.

Williams, M. M. II., R. A. Boydston and A. S. Davis . 2008. Differential tolerance in sweet corn to wild proso millet ( Panicum miliaceum ) interference. Weed Science 56:91-96.


Williams II, M. M., R. A. Boydston and A. S. Davis . 2008. Crop competitive ability contributes to herbicide performance. Weed Res. 48: 58-67.

Davis, A. S. and M. M. Williams II. 2007. Variation in wild proso millet ( Panicum miliaceum ) fecundity in sweet corn has residual effects in snap bean. Weed Sci. 55: 502-507.


Davis, A. S. 2007. Nitrogen fertilizer and crop residue effects on seed mortality and germination of eight annual weed species. Weed Sci. 55: 123-128.

Davis, A. S. and K. A. Renner. 2007. Influence of seed depth and pathogens on fatal germination of velvetleaf ( Abutilon theophrasti ) and giant foxtail ( Setaria faberi ). Weed Sci. 55: 30-35.


Williams, M. M. II., R. A. Boydston and A. S. Davis . 2007. Wild proso millet ( Panicum miliaceum ) suppressive ability among three sweet corn hybrids. Weed Science 55: 245-251.

Davis, A. S. , D. A. Landis, V. Nuzzo, B. Blossey, E. Gerber and H. L. Hinz. 2006. Demographic models inform selection of biocontrol agents for garlic mustard ( Alliaria petiolata ). Ecol. Appl. 16: 2399-2410.


S. Raghu, R. C. Anderson, C. C. Daehler, A. S. Davis, R. N. Wiedenmann, D. Simberloff and R. N. Mack. 2006. Adding biofuels to the invasive species fire? Science 313:1742.

Raghu et al., 2006. Supporting online material.


Williams, M.M.II., R.A. Boydston and A.S. Davis. 2006. Canopy variation among three sweet corn hybrids and implications for light competition. HortScience 41:1449-1454.

Davis, A. S. 2006. When does it make sense to target the weed seedbank? Weed Science. 54:558-565.


Chee-Sanford, J., G. K. Sims, M. M. Williams, II, A. S. Davis. 2006. Do microorganisms influence weed seedbank dynamics? Weed Science. 54: 575-587.

Davis, A. S., K. I. Anderson, S. G. Hallett and K. A. Renner. 2006. Weed seed mortality in soils with contrasting agricultural management histories. Weed Sci. 54: 291-297.


Davis, A. S. , J. Cardina, F. Forcella, G. A. Johnson, G. Kegode, J. L. Lindquist, . C. Luschei, K. A. Renner, C. L. Sprague, and M. M. Williams II. 2005. Environmental factors affecting seed persistence of 13 annual weeds. Weed Science 53: 860-868. 2005.

Landis, D.A., A.S. Davis, and D.W. Schemske. 2005. Predicting garlic mustard biocontrol agent success with demographic modeling. In L.C. Skinner (ed), Proceedings: Symposium on the Biology, Ecology and Management of Garlic Mustard (Alliaria petiolata) and European Buckthorn (Rhamnus cathartica) 17-18 May 2005, University of Minnesota, St. Paul, Minnesota, USA. pp. 7-11.


Davis, A. S. , K. A. Renner and K. L. Gross. 2005. Weed seedbank and community shifts in a long-term cropping systems experiment. Weed Science. 53:296-306.

Davis, A. S. and M. Ngouajio. 2005. Introduction to the symposium Beyond thresholds: applying multiple tactics within integrated weed management systems. Weed Science 53: 368.
Davis, A. S., K. A. Renner, C. L. Sprague, L. Dyer, and D. R. Mutch. 2005. Integrated weed management...One years seeding. Michigan State University Extension Bulletin E-2931.
Davis, A. S., P. Dixon and M. Liebman. 2004. Using matrix models to determine cropping system effects on annual weed demography. Ecological Applications. 14:655-668. 
Davis, A. S. and M. Liebman. 2003. Cropping system effects on giant foxtail demography: I. Green manure and tillage timing. Weed Science 51: 921-929.


Davis, A. S. and M. Liebman. 2003. Cropping system effects on Setaria faberi seedbank dynamics. Asp. Appl. Biol. 69: 83-91.
Davis, A. S., P. Dixon and M. Liebman. 2003. Cropping system effects on giant foxtail demography: II. Retrospective perturbation analysis. Weed Science 51: 930-939.
Davis, A. S. and M. Liebman. 2001. Nitrogen source influences wild mustard growth and competitive effect on sweet corn. Weed Science 49:558-566.
Liebman, M. and A. S. Davis. 2000. Integration of crop, soil and weed management in low-external input systems. Weed Research. 40:27-47.

Ecologist, Global Change and Photosynthesis Research Unit, USDA-ARS
Associate Professor, Crop Sciences, University of Illinois

Adam Davis