Adam S. Davis
Ecologist, Invasive Weed Management Unit, USDA-ARS
Assistant Professor, Crop Sciences, University of Illinois
Faculty member, Program in Ecology and Evolutionary Biology, University of Illinois
Affiliate, Natural Resources and Environmental Sciences, University of Illinois
Phone: (217) 333-9654
Email: Adam.Davis@ars.usda.gov

• B.A., Yale University, Biology
• M.S., University of Maine, Ecology and Environmental Science
• Ph.D. Iowa State University, Crop Production and Physiology

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.

Publications

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. www.sciencemag.org/cgi/content/full/313/5794/1742/DC1

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.