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The Red Queen and the Hard Reds: Productivity Growth in American Wheat, 1800–1940

Published online by Cambridge University Press:  23 January 2003

Alan L. Olmstead
Affiliation:
University of California, Davis, One Shields Ave., Davis, CA 95616-8617; and Agricultural Economics. E-mail: [email protected].
Paul W. Rhode
Affiliation:
The University of North Carolina, Chapel Hill, Chapel Hill, NC 27599 and the National Bureau of Economic Research. E-mail: [email protected].

Abstract

Standard treatments of U.S. agriculture assert that, before the 1930s, productivity growth was almost exclusively the result of mechanization rather than biological innovations. This article shows that U.S. wheat production witnessed wholesale changes in varieties and cultural practices during the nineteenth and early twentieth centuries. Without these changes, vast expanses of the wheat belt could not have sustained commercial production and yields everywhere would have plummeted due to the increasing severity of insects, diseases, and weeds. Revised estimates of Parker and Klein’s productivity calculations indicate that biological innovations contributed roughly half of labor-productivity growth between 1839 and 1909.

Type
Articles
Copyright
Copyright © The Economic History Association 2002

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References

Adusei, Edward O., and Norton, George W.. “The Magnitude of Agricultural Maintenance Research in the USA.” Journal of Production Agriculture 3, no. 1 (1990): 16.CrossRefGoogle Scholar
Alston, J. M., Marra, M. C., Pardey, P. G., and Wyatt, T. J.. “Research Returns Redux: A Meta-Analysis of Agricultural R&D Evaluations.” Australian Journal of Agriculture and Resource Economics 44, no. 2 (2000): 185216.Google Scholar
Alston, J. M., and Pardey, P. G.. “Attribution and Other Problems in Assessing the Returns to Agricultural R&D.” Agricultural Economics 25, nos. 2–3 (September 2001): 141–52.CrossRefGoogle Scholar
Atack, Jeremy, and Passell, Peter. A New Economic View of American History From Colonial Times to 1940. 2nd ed. New York: W.W. Norton, 1994.Google Scholar
Ball, Carleton R.The History of American Wheat Improvement.” Agricultural History 4, no. 2 (1930): 4871.Google Scholar
Ball, Carleton R., and Allen Clark, J.. “Experiments With Durum Wheat.” U.S. Dept. of Agriculture Bulletin, no. 618 (1918).Google Scholar
Bidwell, Percy Wells, and Falconer, John I.. History of Agriculture in the Northern United States, 1620–1860. Washington, DC: Carnegie Institute of Washington, 1925.Google Scholar
Boss, Andrew, Bassett, L. B., Bull, C. P., et al. “Seed Grain.” In Seventeenth Annual Report, Minnesota Agricultural Experiment Station, 363–79. Delano, MN: The Station, 1909.Google Scholar
Buller, A. H. Reginald. Essays on Wheat. New York: Macmillan, 1919.Google Scholar
Bushnell, William R., and Roelfs, Alan P., eds. The Cereal Rusts. Orlando, FL: Academic Press, 1984.Google Scholar
Campbell, C. Lee, and Long, David L.. “The Campaign to Eradicate the Common Barberry in the United States.” In Stem Rust of Wheat: From Ancient Enemy to Modern Foe, edited by Peterson, Paul D., 16–50. St. Paul, MN: APS Press, 2001.Google Scholar
Carleton, Mark Alfred. “The Basis for the Improvement of American Wheats.” U.S. Dept. of Agriculture Division of Vegetable Physiology and Pathology Bulletin, no. 24 (1900).Google Scholar
Carleton, Mark Alfred. “Cereal Rusts of the United States: a Physiological Investigation.” U.S. Dept. of Agriculture Division of Vegetable Physiology and Pathology Bulletin, no. 16 (1899).Google Scholar
Carleton, Mark Alfred. “Hard Wheats Winning Their Way.” In Yearbook, 1914. U.S. Dept. of Agriculture, 391420. Washington, DC: GPO, 1915.Google Scholar
Carrier, Lyman. The Beginnings of Agriculture in America. New York: McGraw-Hill, 1923.Google Scholar
Carroll, Lewis. Through the Looking Glass. Illustrated by Ralph, Steadman. New York: Clarkson N. Potter, 1973.Google Scholar
Cates, H. R.The Weed Problem in American Agriculture.” In Yearbook 1917. U.S. Dept. of Agriculture, 205. Washington, DC: GPO, 1918.Google Scholar
Chester, K. Starr. “Plant Disease Losses: Their Appraisal and Interpretation.” Plant Disease Reporter. Supplement, no. 193 (1950): 189362.Google Scholar
Clark, J. Allen, and Martin, John H.. “Varietal Experiments With Hard Red Winter Wheats in the Dry Areas of the Western United States.” U.S. Dept. of Agriculture Bulletin, no. 1276 (1925).Google Scholar
Clark, J. Allen, Martin, John H., and Ball, Carleton R.. “Classification of American Wheat Varieties.” United States Department of Agriculture Bulletin, no. 1074 (1922).Google Scholar
Clark, J. Allen, and Quisenberry, K. S.. “Distribution of the Varieties and Classes of Wheat in the United States in 1929.” U.S. Dept. of Agriculture Circular, no. 283 (1933).Google Scholar
Clay, Clarence Albert. A History of Maine Agriculture, 1604–1860. University of Maine Studies, Second Series, 68. Onono, ME: University Press, 1954.Google Scholar
“Climatological Summary for Hays, KS.” [Online], Agricultural Research Center-Hays home page, 9 February 2001. <http://www.oznet.ksu.edu/wkarc/Arch/W_History.htm> (21 February 2001).+(21+February+2001).>Google Scholar
Clinton, George Perkins. “Russian Thistle and Some Plants That Are Mistaken for It.” Illinois Agricultural Experiment Station Bulletin, no. 39 (1895): 87118.Google Scholar
Cochrane, Willard W. The Development of American Agriculture: a Historical Analysis. Minneapolis: University of Minnesota Press, 1979.Google Scholar
Collins, Charles W. Ohio, an Atlas. Madison, WI: American Printing & Publishing, Inc., 1975.Google Scholar
Cook, R. James, and Veseth, Roger J.. Wheat Health Management. St. Paul, MN: APS Press, 1991.Google Scholar
Cox, T. S., Shroyer, J. P., Liu Ben-Hui, R. G. Sears, and Martin, T. J.. “Genetic Improvement in Agronomic Traits of Hard Red Winter Wheat Cultivars From 1919–1987.” Crop Science 28 (1988): 756–60.Google Scholar
Craig, Lee A., Haines, Michael R., and Weiss, Thomas. “Development, Health, Nutrition, and Mortality: the Case of the ‘Antebellum Puzzle’ in the United States.” NBER Working Paper Series on Historical Factors in Long Run Growth, Historical paper no. 130, Cambridge, MA, 2000.Google Scholar
Craig, Lee A., Haines, Michael R., and Weiss, Thomas. “U.S. Censuses of Agriculture, by County, 1840–1880.” [computer file] Unpublished files graciously provided by the authors, Dept. of Economics, North Carolina State University, 2000.Google Scholar
Dahms, R. G.Insects Attacking Wheat.” In Wheat Improvement, edited by Quisenberry, K. S. and Reitz, L. P., 411–43. Madison, WI: American Society of Agronomy, 1967.Google Scholar
Dalrymple, Dana G.Changes in Wheat Varieties and Yields in the United States, 1919–1984.” Agricultural History 62, no. 4 (1988): 2036.Google Scholar
“Dickinson Exp Stn, ND (322188) Period of Record Monthly Climate Summary.” [Online], High Plains Regional Climate Center home page, 5 January 2001. <http://www.hprcc.unl.edu/cgi-bin/cli_perl_lib/cliRECtM.pl?nd2188> (21 February 2001).+(21+February+2001).>Google Scholar
Dondlinger, Peter Tracy. The Book of Wheat: an Economic History and Practical Manual of the Wheat Industry. New York: Orange Judd, 1908.Google Scholar
Elliott, E. E., and Lawrence, C. W.. “Some New Hybrid Wheats.” Washington Agricultural Experiment Station Popular Bulletin, no. 9 (1908).Google Scholar
Elwood, Robert B., Arnold, Lloyd E., Clarence Schmutz, D., et al. Changes in Technology and Labor Requirements in Crop Production: Wheat and Oats. Studies of Changing Techniques and Employment in Agriculture, Report no. A-10. Philadelphia: Works Progress Administration, 1939.Google Scholar
Fisher, Franklin M., and Temin, Peter. “Regional Specialization and the Supply of Wheat in the United States, 1867–1914.” Review of Economics and Statistics 52, no. 2 (1970): 134–49.Google Scholar
Fletcher, Stevenson Whitcomb. Pennsylvania Agriculture and Country Life, 1640–1840. Harrisburg: Pennsylvania Historical and Museum Commission, 1950.Google Scholar
Flint, Charles L.Progress in Agriculture.” In Eighty Years’ Progress of the United States, 2102. New York: New National Publishing House, 1864.Google Scholar
Freeman, E. M., and Stakman, E. C.. “Smuts of Grain Crops.” University of Minnesota Agricultural Experiment Station Bulletin, no. 122 (1911).Google Scholar
Goodman, Lowell R., and Jerry Eidem, R.. The Atlas of North Dakota. Fargo: North Dakota Studies, Inc., 1976.Google Scholar
“Grain and Forage Crops.” North Dakota Agricultural Experiment Station (Fargo) Bulletin, no. 10 (1893).Google Scholar
“Grain and Forage Crops.” North Dakota Agricultural Experiment Station (Fargo) Bulletin, no. 11 (1893).Google Scholar
“GrainGenes.” [Online database], Ver. 1.8+. March 2001. <gopher://greengenes.cit.cornell.edu/> (March 2001).+(March+2001).>Google Scholar
Griliches, Zvi. “Agriculture: Productivity and Technology.” In International Encyclopedia of the Social Sciences, vol. 1, 241–45. New York: Macmillan and Free Press, 1968.Google Scholar
Hamilton, Laura M.Stem Rust in the Spring Wheat Area in 1878.” Minnesota History 20, no. 2 (1939): 15664.Google Scholar
Hayami, Yujiro, and Ruttan, Vernon. Agricultural Development: An International Perspective. rev. and exp. ed. Baltim ore: The Johns Hopkins Univ ersity Press, 1985.Google Scholar
“Hays 1 S, KS (143527) Period of Record Monthly Climate Summary.” [Online], High Plains Regional Climate Center home page, 5 January 2001. <http://www.hprcc.unl.edu/cgi-bin/cli_perl_lib/cliRECtM.pl?nd2188> (21 February 2001).+(21+February+2001).>Google Scholar
Headlee, T. J., and Parker, J. B.. “The Hessian Fly.” Kansas Agricultural Experiment Station Bulletin, no. 188 (1913): 83138.Google Scholar
Hecht, Reuben W., and Barton, Glen Y.. “Gains in Productivity of Farm Labor.” U.S. Dept. of Agriculture Technical Bulletin, no. 1020 (1950).Google Scholar
Hedrick, Ulysses Prentiss. A History of Agriculture in the State of New York. New York: New York Agricultural Society, 1933.Google Scholar
Hibbard, Benjamin Horace. The History of Agriculture in Dane County Wisconsin: a Thesis Submitted for the Degree of Doctor of Philosophy, University of Wisconsin, 1902. Bulletin of the University of Wisconsin, 101; Economics and Political Science Series 1, no. 2, (1904): 67214. Madison, WI: 1904.Google Scholar
Hind, H. Y.The Agricultural History of Canada.” In Eighty Years’ Progress of British North America, edited by H. Y. Hind, T. C. Keefer, et al., 32–64. Toronto: L. Nichols, 1865.Google Scholar
Hind, H. Y.. Essay on the Insects and Diseases Injurious to Wheat Crops. Toronto: Lovell & Gibson, 1857.Google Scholar
Hughes, Jonathan R. T. American Economic History. Glenview, IL: Scott, Foresman, 1987.Google Scholar
Hyslop, J. A. Losses Occasioned by Insects, Mites, and Ticks in the United States. Washington, DC: United States Bureau of Entomology and Plant Quarantine, Division of Insect Pest Survey and Information, 1938.Google Scholar
Johnson, D. Gale. “Agriculture and the Wealth of Nations.” American Economic Review 87, no. 2 (1997): 112.Google Scholar
Johnson, D. Gale, and Gustafson, Robert L.. Grain Yields and the American Food Supply: an Analysis of Yield Changes and Possibilities. Chicago: University of Chicago Press, 1962.Google Scholar
Kiesselbach, T. A.Winter Wheat Investigations.” Nebraska Agricultural Experiment Station Research Bulletin, no. 31 (1925).Google Scholar
Klose, Nelson. America's Crop Heritage: the History of Foreign Plant Introduction by the Federal Government. Ames: Iowa State College Press, 1950.Google Scholar
Klippart, John H. The Wheat Plant: Its Origin, Culture, Growth, Development, Composition, Varieties, Diseases, Etc., Etc. New York: A. O. Moore & Company, 1860.Google Scholar
, Jr. First the Seed: The Political Economy of Plant Biotechnology, 1942–2000. New York: Cambridge University Press, 1988.Google Scholar
Knopf, Henry A. “Changes in Wheat Production in the United States.” Ph.D. Thesis, Cornell University, 1967.Google Scholar
Large, E. C. The Advance of Fungi. New York: Henry Holt, 1940.Google Scholar
Libecap, Gary, and Hansen, Zeynep Kocabiyik. “‘Rain Follows the Plow’ and Dryfarming Doctrine: The Climate Information Problem and Homestead Failure in the Upper Great Plains, 1890–1925.” This JOURNAL 62, no. 1 (2002): 86120.Google Scholar
Loegering, W. Q., Johnston, C. O., and Hendrix, J. W.. “Wheat Rusts.” In Wheat Improvement, edited by Quisenberry, K. S. and Reitz, L. P., 307–35. Madison, WI: American Society of Agronomy, 1967.Google Scholar
Loomis, Ralph A., and Barton, Glen T.. “Productivity of Agriculture: United States, 1870– 1958.U.S. Dept. of Agriculture Technical Bulletin, no. 1238 (1961).Google Scholar
Malin, James C. Winter Wheat in the Golden Belt of Kansas. Lawrence: University of Kansas Press, 1944.Google Scholar
Marlatt, C. L.The Annual Losses Occasioned by Destructive Insects in the United States.” In Yearbook for 1904, United States Department of Agriculture, 461–74. Washington, DC: GPO, 1905.Google Scholar
Marlatt, C. L.. “The Principal Insect Enemies of Growing Wheat.” Farmers’ Bulletin, no. 132 (1901).Google Scholar
Marlatt, C. L.. “Losses Due to Insects, Part I, Insects as a Check on Agricultural Production and as a Source of Waste to Accumulated Supplies.” Report of the National Conservation Commission, Vol. 3, pp. 301–09, 60th Cong. 2nd Sess. Senate Document No. 676 (1909).Google Scholar
McColloch, James W.The Hessian Fly in Kansas.” Kansas Agricultural Experiment Station Technical Bulletin, no. 11 (1923).Google Scholar
Metcalf, Clell Lee, and Flint, Wesley Pillsbury. Destructive and Useful Insects: Their Habits and Control. 4th ed. New York: McGraw Hill, 1962.Google Scholar
Midwestern Regional Climate Center. “Historical Climate Summaries for Wooster_Exp_Stn, OH.” [Online], Midwest Climate Watch home page, 26 January 2000. <http://mcc.sws.uiuc.edu/Summary/Html/339312.html> (21 February 2001).+(21+February+2001).>Google Scholar
Miller, J. D., Hosford, R. M., Stack, R. W., et al. “Diseases of Durum Wheat.” In Durum Wheat: Chemistry and Technology, edited by Fabriani, Giuseppe and Lintas, Claudia, 6692. St. Paul, MN: American Association of Cereal Chemists, 1988.Google Scholar
Minnesota Agricultural Experiment Station. 1894 Annual Report. St. Paul, MN: Pioneer Press Co, 1895.Google Scholar
Montgomery, E. G.Wheat Breeding Experiments.” Nebraska Agricultural Experiment Station Bulletin, no. 125 (1912).Google Scholar
Murray, Stanley N. The Valley Comes of Age: A History of Agriculture in the Valley of the Red River of the North, 1812–1920. Fargo: North Dakota Institute for Regional Studies, 1967.Google Scholar
Norrie, K. H.The Rate of Settlement of the Canadian Prairies, 1870–1911.” This JOURNAL 35, no. 2 (1975): 410–27.Google Scholar
Oerke, Erich-Christain. “Estimated Crop Losses Due to Pathogens, Animal Pests, and Weeds.” In Crop Production and Crop Protection: Estimated Losses in Major Food and Cash Crops, edited by Oerke, Erich-Christain, Dehne, Heinz-Wilhelm, Schönbeck, Fritz, et al., 72741. Amsterdam: Elsevier, 1994.Google Scholar
Ohio State Board of Agriculture. Annual Report for the Year 1857. Columbus, OH: State Printer, 1858.Google Scholar
Olmstead, Alan L., and Rhode, Paul W.. “Biological Innovation in American Wheat Production: Science, Policy, and Environmental Adaptation.” In Industrializing Organisms, edited by Scranton, Philip. London: Routledge Press, forthcoming.Google Scholar
Pardey, Philip G., Alston, Julian M., Christian, Jason E., et al. Hidden Harvest: U.S. Benefits From International Research Aid. Food Policy Report. Washington, DC: International Food Policy Research Institute, 1996.Google Scholar
Parker, William N. “Agriculture.” In American Economic Growth, Davis, Lance E., Easterlin, Richard A., Parker, William N., et al., 369417. New York: Harper & Row, 1972.Google Scholar
Parker, William N. Europe, America, and the Wider World: Essays on the Economic History of Western Capitalism. America and the Wider World, 2. New York: Cambridge University Press, 1991.Google Scholar
Parker, William N.. “Productivity Growth in American Grain Farming: An Analysis of Its 19th-Century Sources.” In The Reinterpretation of American Economic History, edited by Fogel, Robert W. and Engerman, Stanley L., 175–86. New York: Harper & Row, 1971.Google Scholar
Parker, William N., and Klein, Judith. “Productivity Growth in Grain Production in the United States, 1840–60 and 1900–10.” In Output, Employment, and Productivity in the United States After 1800, 523–80. New York: Columbia University Press for NBER, 1996.Google Scholar
Patterson, F. L., and Allan, R. E.. “Soft Wheat Breeding in the United States.” In Soft Wheat: Production, Breeding, Milling, and Uses, edited by Yamazaki, W. T. and Greenwood, C. T., 3641. St. Paul, MN: American Association of Cereal Chemists, 1981.Google Scholar
Patton, P.The Relationship of Weather to Crops in the Plains Region of Montana.” Montana Agricultural Experiment Station Bulletin, no. 206 (1927).Google Scholar
Paullin, Charles O. Atlas of the Historical Geography of the United States. Washington, DC: Carnegie Institution, 1932.Google Scholar
Peterson, R. F. Wheat. London: Leonard Hill Books, 1965.Google Scholar
The Plant Disease Bulletin. Vols. 1–6. Washington, DC: U.S. Dept. of Agriculture, Bureau of Plant Industry, 1917–1922.Google Scholar
The Plant Disease Reporter. Vols. 7–22. Washington, DC: U.S. Dept. of Agriculture, Bureau of Plant Industry, 1923–1939.Google Scholar
Pritchett, John Perry. The Red River Valley, 1811–1849: A Regional Study. New Haven, CT: Yale University Press, 1942.Google Scholar
Quisenberry, Karl S., and Reitz, L. P.. “Turkey Wheat: the Cornerstone of an Empire.” Agricultural History 48, no. 10 (1974): 98114.Google Scholar
Ratner, Sidney, Soltow, James H., and Sylla, Richard. The Evolution of the American Economy. New York: Macmillan Publishing, 1993.Google Scholar
Roberts, I. P., Slingerland, M. V., and Stone, J. L.. “The Hessian Fly: Its Ravages in New York in 1901.” Cornell University Agricultural Experiment Station Bulletin, no. 194 (1901): 239–60.Google Scholar
Roelfs, Alan P.Effects of Barberry Eradication on Stem Rust in the United States.” Plant Disease 66, no. 2 (1982): 177–81.Google Scholar
Roelfs, Alan P.. “Estimated Losses Caused by Rust in Small Grain Cereals in the United States, 1918–76.” U.S. Dept. of Agriculture Miscellaneous Publication, no. 1363 (1978).Google Scholar
Salmon, S. C.Climate and Small Grain.” Yearbook of Agriculture, 1941, U.S. Dept. of Agriculture, 334–35. Washington, DC: GPO, 1942.Google Scholar
Salmon, S. C.. “Developing Better Varieties of Wheat for Kansas.” In Wheat in Kansas, 210–17. Topeka: Kansas State Board of Agriculture, 1920.Google Scholar
Salmon, S. C., Mathews, O. R., and Luekel, R. W.. “A Half Century of Wheat Improvement in the United States.” In Advances in Agronomy, edited by Norman, A. G., 1145. Vol. 5. New York: Academic Press, 1953.Google Scholar
Schafer, E. G., Gaines, E. F., and Barbee, O. E.. “Wheat Varieties in Washington.” Washington Agricultural Experiment Station Bulletin, no. 207 (1926).Google Scholar
Schmidt, Hubert G. Agriculture in New Jersey: A Three-Hundred-Year History. New Brunswick, NJ: Rutgers University Press, 1973.Google Scholar
Sechrist, Robert P. Basic Geographic and Historic Data for Interfacing ICPSR Data Sets, 16201983 [United States] [Computer file]. ICPSR version. Baton Rouge, LA: Robert P. Sechrist, Louisiana State University [producer], 1984. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2000.Google Scholar
Socolofsky, Homer E., and Huber Self. Historical Atlas of Kansas. Norman: University of Oklahoma Press, 1972.Google Scholar
Statistics of Grain Crops, 1921. Wheat.” In Yearbook 1921, U.S. Dept. of Agriculture, 530–31. Washington, DC: GPO, 1922.Google Scholar
Stanelle, Jim. “Certified: This Seed Will Inspire Trust and Confidence.” Seed World. (June 1999) p. 18.Google Scholar
Stucky, Harley J. A Century of Russian Mennonite History in America. North Newton, KS: Mennonite Press, 1973.Google Scholar
Talley, Steven. “Hessian fly genomics research will benefit wheat farmers, others.” Purdue News. (March 2001). http://www.purdue.edu/UNS/html4ever/010119.Stuart.hessian.html. (12 December 2001).Google Scholar
Todd, Sereno Edwards. The American Wheat Culturist: A Practical Treatise on the Culture of Wheat, Embracing a Brief History and Botanical Description of Wheat, With Full Practical Details for Selecting Seed, Producing New Varieties, and Cultivating on Different Kinds of Soil. New York: Taintor Brothers, 1868.CrossRefGoogle Scholar
U.S. Bureau of the Census. Historical Statistics of the United States on CD-ROM: Colonial Times to 1970. Bicentennial edition, electronic edition. Edited by Carter, Susan B., Scott Sigmund Gartner, Haines, Michael R., et al. New York: Cambridge University Press, 1997.Google Scholar
U.S. Bureau of the Census. Statistical Atlas of the United States. Washington, DC: GPO, 1925.Google Scholar
U.S. Bureau of the Census. Thirteenth Census of the United States Taken in the Year 1910. Vols. 6–7. Agriculture: 1909 and 1910, Reports by States, With Statistics for Counties. Washington, DC: GPO, 1913.Google Scholar
U.S. Census Office. Agriculture of the United States in 1860: Compiled From the Original Returns of the Eighth Census. Washington, DC: GPO, 1864.Google Scholar
U.S. Dept. of Agriculture. Report of the Commissioner of Agriculture for the Year 1866. Washington, DC: GPO, 1867.Google Scholar
U.S. Patent Office. Annual Report of the Commissioner of Patents. Agriculture. Vols. 1847 –1855. Washington, DC: GPO, 18481856.Google Scholar
Van Valen, L.A New Evolutionary Law.” Evolutionary Theory. 1 (1973): 130.Google Scholar
Walton, Gary M., and Rockoff, Hugh. History of the American Economy. Orlando, FL: Dryden Press, 1998.Google Scholar
Ward, Tony. “The Origins of the Canadian Wheat Boom, 1880–1910.” Canadian Journal of Economics 27, no. 4 (1994): 864–83.Google Scholar
Weather Extremes - Hays, KS.” [Online], Agricultural Research Center-Hays home page, 9 February 2001. <http://www.oznet.ksu.edu/wkarc/Arch/W_Extremes.htm> (21 February 2001).+(21+February+2001).>Google Scholar
Webster, F. M.The Hessian Fly.” Ohio Agricultural Experiment Station Bulletin, no. 107 (1899): 257–88.Google Scholar