Corn Invertebrate Loss Estimates from the United States and Ontario, Canada — 2021
Published: 07/22/2022
DOI: doi.org/10.31274/cpn-20220722-0
CPN-2019-21
*Data updated 13 April 2023: Minnesota is now grouped with the western rather than the Great Lakes region states to better reflect growing conditions present in Minnesota corn production areas.
Invertebrate pests (namely insects, mites, and slugs) annually reduce corn yield in the United States and Canada. The abundance and impacts of these pests vary from year to year, and their effect on yield is based on many factors, including weather conditions, crop production practices, and hybrid selection and susceptibility to invertebrate feeding.
Extension workers representing 25 corn-producing U.S. states and Ontario, Canada, estimated the percent yield loss from corn invertebrate pests. These reports account for nearly 13.6 billion bushels (87.6 percent) of the total corn produced in the U.S. and Ontario in 2021 (Figure 1). The yield loss estimates include foliar, root, ear, and stalk feeding invertebrate pests.
This publication documents the impact of major invertebrate pests on corn production during 2021. Extension entomologists began tracking this data in 2021 and will revise estimates annually. It is important to note that methods for estimating losses from invertebrate pests vary by state or province. The estimates may be based on statewide surveys, personal experience, and feedback from university extension personnel, industry representatives, and growers.
Maximum yield before losses due to invertebrates was estimated for each state or province using this formula:
(total harvested bushels/[{100 – percent estimated invertebrate pest loss}/100])
Total bushels lost per invertebrate pest were then formulated ([percent loss/100] x yield before estimated loss) for each state or province. U.S. and Canadian growers have expenses to control invertebrate pests of corn in the form of plant-incorporated protectant fees (included in the cost of seed and not easily estimable), seed-applied insecticides, and soil and foliar insecticides and acaricides. These expenses to prevent potential losses are not included in our calculations; thus, the values in this publication underestimate the impact of invertebrate pests in U.S. and Canadian corn production.
Figure 1. Proportion of 2021 corn production by state or province for the 25 U.S. states and Ontario, Canada that participated in this survey. This figure represents 87.6 percent of the 15.5 billion bushels of corn produced across the entire U.S. and in Ontario, Canada.
Figure 2. Corn rootworms were estimated to reduce overall yield in the U.S. by nearly 600 million bushels in 2021, more than three times the impact of any other invertebrate pest. A western corn rootworm adult (left) and corn root injury (right).
Daren Mueller (left) and Ashley Dean (right)
2021 Conditions and Corn Production
The U.S. produced 15.1 billion bushels of corn in 2021, while the province of Ontario, Canada produced 0.4 billion bushels. The continental U.S. experienced above average temperatures in 2021. Much of the western U.S. experienced below average precipitation. Above average levels of precipitation occurred across many eastern U.S. states; dry conditions can exacerbate the impact of insect injury to roots.
Overall 2021 Invertebrate Losses
In 2021, invertebrate pests reduced corn yield by an estimated 8.9 percent across 25 states and by 1.1 percent in Ontario, translating into an overall loss of 1.3 billion bushels. Corn rootworm was estimated to cause the greatest yield loss overall (Figure 2). Other important invertebrate pests in terms of yield loss were western bean cutworm, twospotted spider mite, corn earworm, and Banks grass mite. Table 1 provides yield loss estimates for invertebrate pests typically reported in corn production in the U.S. and Canada.
Table 1. Estimated corn yield losses (thousands of bushels) due to invertebrate pests in 25 U.S. corn-producing states1 and Ontario, Canada in 2021.
Invertebrate pest | Total U.S. losses (thousands of bushels) | Total Ontario losses (thousands of bushels) |
---|---|---|
Corn rootworms2 | 599,354.6 | 3,771.5 |
Western bean cutworm | 187,232.2 | 377.2 |
Twospotted spider mite | 148,890.0 | 0.4 |
Corn earworm | 139,357.0 | 0.4 |
Banks grass mite | 110,492.1 | 0.0 |
Grasshopper (multiple species) | 28,322.6 | 0.0 |
Black cutworm | 23,501.2 | 0.0 |
Slugs (multiple species) | 9,474.6 | 0.0 |
Seedcorn maggot | 8,990.8 | 0.4 |
Stink bugs3 | 7,338.7 | 0.0 |
Wireworm (multiple species) | 4,930.7 | 0.0 |
Grubs4 | 3,299.6 | 0.4 |
Southwestern corn borer | 2,348.3 | 0.0 |
True armyworm | 1,930.7 | 0.0 |
Hop vine borer | 1,457.7 | 0.0 |
Other arthropods5 | 1,396.0 | 0.0 |
Cornsilk fly | 1,213.6 | 0.0 |
Other cutworms6 | 924.5 | 0.0 |
Fall armyworm | 653.9 | 0.4 |
Stalk borer | 609.4 | 0.0 |
European corn borer | 338.6 | 0.4 |
Sap beetle | 255.8 | 0.0 |
Billbugs | 161.8 | 3.8 |
Asiatic garden beetle | 64.8 | 0.0 |
Aphids7 | 26.4 | 0.0 |
Sugarcane beetle | 9.6 | 0.0 |
Colaspis beetles8 | 4.8 | 0.0 |
Corn flea beetle | 2.6 | 0.0 |
Yellowstriped armyworm | 2.6 | 0.0 |
Cereal leaf beetle | 0.1 | 0.0 |
Beet armyworm | 0.0 | 0.0 |
Chinch bug | 0.0 | 0.0 |
Corn blotch leafminer | 0.0 | 0.0 |
Corn thrips | 0.0 | 0.0 |
Leafroller9 | 0.0 | 0.0 |
Lesser cornstalk borer | 0.0 | 0.0 |
Seedcorn beetle and slender seedcorn beetle | 0.0 | 0.0 |
Sod webworm | 0.0 | 0.0 |
Sugarcane borer | 0.0 | 0.0 |
1 Alabama, Arkansas, Colorado, Delaware, Georgia, Illinois, Iowa, Kansas, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Mississippi, Nebraska, New York, North Carolina, North Dakota, Ohio, South Carolina, South Dakota, Tennessee, Texas, Virginia, and Wisconsin. 2 Diabrotica barberi, D. virgifera virgifera, and D. undecimpunctata howardi. 3 Chinavia hilaris, Euschistus spp., Halyomorpha halys, and Nezara viridula. 4 Popillia japonica (immature) and Phyllophaga spp. 5 Popillia japonica (adult) and Systena frontalis. 6 Nephelodes minians, Feltia jaculifera, Apamea devastator, Euxoa detersa, and Peridroma saucia. 7 Rhopalosiphum padi, R. maidis, and Aphis protaphis middletonii. 8 Colaspis brunnea and Colaspis crinicornis 9 Choristoneura parallela and Xenotemna pallorana.
Invertebrate Pests by Production Region
The states reporting data from the western corn-growing region accounted for 64.7 percent of corn production in the U.S. and Ontario. Corn rootworms caused the most injury in this region (Table 2), due to the high amount of intensive continuous corn and Bt resistance in rootworm populations. Caterpillar and mite pests caused the greatest estimated yield losses after corn rootworm.
The states reporting data from the Great Lakes region accounted for 13.0 percent of corn production in the U.S. and Ontario. Similar to the western region, corn rootworms caused the greatest amount of estimated yield loss (Table 3). Black cutworm, western bean cutworm, seedcorn maggot, and slugs caused the next greatest losses, in descending order. In this region, it is estimated that 5.0 percent of corn yield was lost due to invertebrate activity.
The states reporting data for the Southern region represented 10.0 percent of the total corn produced in the U.S. and Ontario in 2021. Overall, losses due to corn invertebrate pests across southern states were low (1.2 percent) (Table 4) compared to the western corn-growing region (10.4 percent) in 2021. Stink bugs (Figure 3) caused the greatest injury in the southern states, followed by corn rootworms, twospotted spider mite, and Banks grass mite.
Table 2. Estimated corn yield losses due to the five most significant invertebrates in western corn-growing U.S. states1 in 2021.
Rank | Invertebrate Pest | Total losses (thousands of bushels) | |
---|---|---|---|
Region | U.S. | ||
1 | 1 | Corn rootworms2 | 540,357 |
2 | 2 | Western bean cutworm | 179,635 |
3 | 3 | Twospotted spider mite | 146,388 |
4 | 4 | Corn earworm | 138,047 |
5 | 5 | Banks grass mite | 108,051 |
1 Colorado, Illinois, Iowa, Kansas, Minnesota, Nebraska, North Dakota, and South Dakota. 2 Diabrotica barberi, D. virgifera virgifera, and D. undecimpunctata howardi.
Table 3. Estimated corn yield losses due to the five most significant invertebrates in the Great Lakes region of the U.S.1 and Ontario, Canada in 2021.
Rank | Invertebrate Pest | Total losses (thousands of bushels) | |
---|---|---|---|
Region | U.S. | ||
1 | 1 | Corn rootworms2 | 60,213 |
2 | 7 | Black cutworm | 10,530 |
3 | 2 | Western bean cutworm | 7,972 |
4 | 9 | Seedcorn maggot | 7,650 |
5 | 8 | Slugs (multiple species) | 7,650 |
1 Michigan, New York, Ohio, and Wisconsin. 2 Diabrotica barberi, D. virgifera virgifera, and D. undecimpunctata howardi.
Table 4. Estimated corn yield losses due to the five most significant invertebrates in southern U.S. states1 in 2021.
Rank | Invertebrate Pest | Total losses (thousands of bushels) | |
---|---|---|---|
Region | U.S. | ||
1 | 10 | Stink bugs2 | 6,805 |
2 | 1 | Corn rootworms3 | 2,557 |
3 | 3 | Twospotted spider mite | 2,441 |
4 | 5 | Banks grass mite | 2,441 |
5 | 13 | Southwestern corn borer | 1,805 |
1 Alabama, Arkansas, Delaware, Georgia, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, South Carolina, Tennessee, Texas, and Virginia. 2 Chinavia hilaris, Euschistus spp., Halyomorpha halys, and Nezara viridula. 3 Diabrotica barberi, D. virgifera virgifera, and D. undecimpunctata howardi.
Figure 3. Stink bugs caused the greatest injury in the southern U.S. A brown marmorated stink bug adult is shown here.
Adam Sisson
Disclaimer
The invertebrate pest loss estimates in this publication were provided by extension workers from across the U.S. and from Ontario, Canada. This information is only a guide. The values in this publication are not intended to be exact measures of corn yield losses due to invertebrate pests, since they were not quantitatively measured. Participants assume no liability resulting from the use of these estimates. Hence, these losses should be approached with caution when examined for a particular state. However, they can be useful to compare general trends across years or across regions within a given year.
Values reported in this document were accurate as of publication date and do not reflect corrections or updates occurring since that time.
Acknowledgments
Authors
Dominic Reisig, North Carolina State University; Katelyn Kesheimer, Auburn University; Nick Bateman and Glenn Studebaker, University of Arkansas; Ron Meyer, Colorado State University; Francis Reay-Jones, Clemson University; Elson Shields, Cornell University; David Owens, University of Delaware; G. David Buntin, University of Georgia; Nicholas Seiter, University of Illinois; Erin Hodgson and Adam Sisson, Iowa State University; Anthony Zukoff, Kansas State University; Raul Villanueva, University of Kentucky; Tyler Towles, Louisiana State University; Kelly Hamby, University of Maryland; Chris DiFonzo, Michigan State University; Bill Hutchison and Bruce Potter, University of Minnesota; Angus Catchot and Don Cook, Mississippi State University; Jeffrey Bradshaw and Julie Peterson, University of Nebraska; Patrick Beauzay and Janet Knodel, North Dakota State University; Kelley Tilmon, Ohio State University; Tracey Baute, Ontario Ministry of Agriculture, Food and Rural Affairs; Adam Varenhorst, South Dakota State University; Sebe Brown, University of Tennessee; David Kerns and Pat Porter, Texas A&M University; Sally Taylor, Virginia Tech; and Bryan Jensen, University of Wisconsin-Madison.
Data Compilation
Dominic Reisig, North Carolina State University
Sponsors
In addition to support from United States Department of Agriculture - National Institute of Food and Agriculture, this project was funded in part through the National Corn Growers Association, the Grain Farmers of Ontario as well as through local and regional commodity check off programs.
Production data including total harvested bushels for each state was obtained from the United States Department of Agriculture-National Agriculture Statistics Service and the Ontario Ministry of Agriculture Food and Rural Affairs. Climate information from the National Oceanic and Atmospheric Administration-National Center for Environmental Information.
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