Russell R. Hahn
Weed Science

238 Emerson Hall (607)255-1759 E-mail: rrh4@cornell.edu B.S. 1964 (University of Nebraska) M.S. 1968 (University of Nebraska) Ph.D. 1974 (Texas A&M University) Russell R. Hahn, an Associate Professor of Crop and Soil Sciences, joined the Cornell faculty in 1988. Prior to his appointment to the faculty he was an extension associate (1974-1980) and senior extension associate (1980-1988) in the Department of Agronomy at Cornell. Professor Hahn serves as Department Extension Leader and as extension weed control specialist for field crops in New York State. His field research on weed management strategies provides information for extension programming and serves as the basis for the college’s field crop weed control guidelines. He is a Distinguished Member of the Northeastern Weed Science Society and a Fellow of the Weed Sciences Society of America.

Research Program Much of Dr.Hahn's research has focused on the development of control recommendations for troublesome annual broadleaf weeds such as velvetleaf (Abutilon theophrasti Medicus.) and triazine-resistant biotypes of common lambsquarters (Chenopodium album L.) in corn. The emphasis of this research shifts as weed control and other cropping practices selectively favor the survival of certain weed species or biotypes. Triazine-resistant biotypes of both common groundsel (Senecio vulgaris L.) and common ragweed (Ambrosia artemisiifolia L.) are surviving current weed control practices and are the focus of current research. Renewed interest in no-tillage/zone-tillage production systems and the introduction of herbicide-resistant crops has led to expanded efforts in determining the role of residual herbicides and the importance of application timing in total post emergence weed control programs.

Selected Publications Hahn, R.R. and P.J. Stachowski. 2004. Roughstalk bluegrass suppression in alfalfa/grass hayfields. Proc. Northeastern Weed Sci. Soc. 58:1. Hahn, R.R. and P.J. Stachowski. 2003. Common ragweed problems and control in field corn. What’s Cropping Up? 13(5):6-7. Hahn, R.R. and P.J. Stachowski. 2003. Total post emergence weed control in corn - revisited. What’s Cropping Up? 12(1):1-3. Hahn. R. R. and P.J. Stachowski. 2001. Residual herbicides improve post emergence large crabgrass control in corn. What's Cropping Up? 11 (5) 6. Hahn, R.R. and P.J. Stachowski. 2001. Effect of residual herbicides and application timing on efficiency of glyphosate-resistant soybeans. . Proc Northeastern Weed Sci. Soc. 55:28. Hahn, R. R. and P.J. Stachowski. 2000. Effect of conventional and Roundup Ready weed control programs on yellow nutsledge tuber populations. What's Cropping Up? 10 (5): 6-7. Hahn, R.R. And P.J. Stachowski. 1998. Reduced herbicide rates for narrow-row silage corn. Weed Sci. Soc. Am. Abstracts 38:2. Hahn, R.R., 1998. Postemergence herbicides control triazine-resistant common ragweed and common groundsel. What's Cropping Up? 8(2):3. Hahn, R.R. and P.J. Stachowski. 1998. Wirestem muchly control with herbicide-resistant corn hybrids. What's Cropping Up? 8(4):4. Hahn, R.R. and P.J. Stachowski. 1999. Factors affecting silage and grain yields with glufosinate- and glyphosate- resistant corn. Proc. Northeastern Weed Sci. Soc. 53:67. Hahn, R.R. and P.J. Stachowski. 1999. Timing of total postemergence weed control progressive less critical for soybeans than for corn. What's Cropping Up? 9(3): 2-3.