Herbicide Adoption Contributed Greatly to Increased Corn Production


Corn yields tripled in the U.S. between the 1930s and 1980s. Many new technologies and practices contributed to this increase in corn yields: hybrids, fertilizers, herbicides, insecticides, increased plant populations, early planting. A researcher at the University of Minnesota studied all of these factors to determine their contribution to the increase and determined that herbicides contributed about ¼ of the increase due to better weed control.

“Corn (Zea mays L.) yields in Minnesota have increased from the 2,010 kg/ha yield level of the pre-1930’s to the current 6,290 kg/ha average. This increased yield can be attributed to a series of technological, cultural, and management practices adopted by farmers. My objective is to attempt an analysis of the magnitude of the changes and the relative contributions to grain yield each practice has made over the 50-year time period.

Improved weed control by the use of herbicides on 93% of the hectarage has increased yields 23%.”

Author: Cardwell, V. B.
Affiliation: University of Minnesota, St. Paul.
Title: Fifty years of Minnesota corn production: sources of yield increase.
Source: Agronomy Journal. 1982. 74[November-December]:984-990.

Tight Market Standards For Sweet Corn Necessitate Insecticide Sprays

Bugs in corn

Worms in sweet corn

Consumer surveys show that the lack of insect damage is the most important factor when deciding which sweet corn to buy. Processors and stores require larval infestations to be < 5-10% of sweet corn ears. To meet those standards, sweet corn growers throughout the U.S. must use insecticides.

”Minnesota is the second largest producer of processing sweet corn, Zea mays L., in the United States with an annual production of >53,000 ha; the state also produces ≈4,000 ha for fresh market. The European corn borer, Ostrinia nubilalis (Hübner), and corn earworm, Helicoverpa zea (Boddie), continue to be the most important insect pests of sweet corn in the upper Midwest. To minimize economic risks associated with insect damage in sweet corn, most growers rely on insecticides to manage these pests.

Most processors and fresh market growers require larval infestations and brown kernel incidence to be <5-10% of harvested ears.”

”Sweet corn is the most commonly grown vegetable crop in Pennsylvania. Most is grown for fresh-market. Stringent control is required to meet market standards and most acreage (~80%) is sprayed to control corn earworm, fall armyworm, and European corn borer.”

Authors: O’Rourke, P. K., and W. D. Hutchison.
Affiliation: Department of Entomology, University of Minnesota.
Title: Binomial sequential sampling plans for late instars of European corn borer (Lepidoptera: Crambidae), corn earworm (Lepidoptera: Noctuidae), and damaged kernels in sweet corn ears.
Source: J. Econ. Entomol. 2004. 97[3]:1003-1008.

Author: Fleischer, S.
Affiliation: Department of Entomology, Penn State University.
Title: Regional patterns in corn borer and fall armyworm populations: implications for management.
Source: 58th New Jersey Agricultural Convention and Trade Show. 2013 Proceedings. February 5-7. Pgs. 118-119.

Fungal Growth on Sugarbeet Leaves Would Lower U.S. Sugar Production

Fungicide Treatment (Left: Treated - Right: Untreated)

Fungicide Treatment (Left: Treated – Right: Untreated)

The Red River Valley in North Dakota and Minnesota is a major sugarbeet production area. About ½ of U.S. sugar comes from sugarbeets. A disease on the leaves damages the plant’s ability to produce extractable sucrose in the roots. Fungicides kill the fungus before the damage is done to the plants.

“Cercospora leaf spot is the most economically damaging foliar disease of sugarbeet in Minnesota and North Dakota. The disease reduces root yield and sucrose concentration, and increases impurity concentrations resulting in reduced extractable sucrose and higher processing losses.”

“It is difficult to combine high levels of Cercospora leaf spot resistance with high recoverable sucrose in sugarbeet. Consequently, commercial varieties generally have only moderate levels of resistance and require fungicide applications to obtain acceptable levels of protection against Cercospora leaf spot under moderate and high disease severity.”

Authors: M.F.R. Khan1 and A.L. Carlson2
1North Dakota State University & University of Minnesota; 2Plant Pathology Department, North Dakota State University
Title: Efficacy of fungicides for controlling Cercospora leaf spot on sugarbeet.
Publication: Sugarbeet Research & Education Board of Minnesota and North Dakota. 2011 Research report available at: http://www.sbreb.org/Research/research.htm.

Commercial Wild Rice Production in Minnesota Depends on Fungicides

Wild rice originated in Minnesota and the surrounding Great Lakes. It is the only cereal native to North America that has been domesticated from a wild plant. Before commercial production began, wild rice was difficult to obtain. The first commercial field of wild rice was planted in 1950 in Minnesota. After one season, fungal brown spot disease destroyed the second crop. In the next decade, fungal brown spot destroyed much of Minnesota’s wild rice crops – epidemics in 1973 and 1974 resulted in complete crop loss in many paddies. Ever since 1974 Minnesota growers have sprayed fungicides in order to produce commercial wild rice.

“Propiconazole, a systemic ergosterol biosynthesis-inhibiting fungicide, was evaluated for FBS control during 1985-1987 at the University of Minnesota North Central Experiment Station in Grand Rapids. In 1985 and 1986, propiconazole applications at both boot and heading stages of development increased yield by 68 and 40%, respectively, and in 1987 applications increased yield 113%.”

“Registration of propiconozale is crucial, because commercial wild rice production in Minnesota without fungicides may not be economically feasible.”

Author: D.R. Johnson and J.A. Percich
Affiliation: University of Minnesota, St. Paul
Title: Wild rice domestication, fungal brown spot disease, and the future of commercial production in Minnesota.
Publication: Plant Disease. 1992. December:1193-1198.

Modern Fungicides Continue Control of Potato Disease

The disease of potatoes known as ‘early blight’ occurs earlier in the season than the well-known ‘late blight’ disease. Early blight is a significant problem in Wisconsin and Minnesota potato fields. Fungicides have been used for over 100 years to protect potatoes from early blight. Recent research in Wisconsin shows that modern fungicides continue to be most effective with newer chemistries expected to continue effective control into the future.

“Potato early blight is a perennial and potentially destructive disease caused by the fungus Alternaria solani. Appropriately-timed, effective fungicides are necessary to limit yield and quality loss. In 2010, we evaluated 38 fungicide programs for early blight control at the University of Wisconsin Hancock Agricultural Research Station on ‘Russet Burbank.’ Programs included an untreated control, conventional and organic grower standard programs, and newer chemistries.”

“The highest yielding program was the Wisconsin conventional grower standard. Organic treatments were ineffective. Several newer chemistries and modified standard programs were effective. At this time, and in the registration pipeline, there are excellent fungicides for the control of potato early blight that will contribute to good fungicide resistance management practices.”

Authors: Kenneth Cleveland, Jamie Dobbs, Rosemary Clark and Amanda Gevens
Affiliation: University of Wisconsin-Madison, Dept. of Plant Pathology
Title: Evaluating the efficacy of fungicide programs for the control of potato early blight in the Central Sands of Wisconsin.
Publication: American Journal of Potato Research (2012) 89:32.