Corn Invertebrate Loss Estimates from the United States and Ontario, Canada — 2025

Invertebrate pests (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 effects on yield depend on many factors, including weather conditions, crop production practices, and hybrid selection that influences susceptibility to invertebrate feeding. 

The U.S. produced more than 17.0 billion bushels of corn in 2025, while the province of Ontario, Canada, produced nearly 0.4 billion bushels. Extension specialists representing 28 corn-producing U.S. states and Ontario, Canada, estimated the percent yield loss from corn invertebrate pests. These reports account for more than 16.9 billion bushels (97.3 percent) of the total corn produced in the U.S. and Ontario in 2025 (Figure 1). The yield loss estimates include invertebrate pests that feed on foliar, root, ear, and stalk tissue. Yield-loss estimates do not include diseases transmitted by invertebrates. Estimates are mostly for grain corn (including non-Bt hybrids) but can also include popcorn, silage, and sweet corn. 

This publication documents the impact of major invertebrate pests on corn production during 2025. Extension entomologists began tracking these data in 2021 and 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 farmers. 

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 farmers also have expenses to control invertebrate pests of corn, including technology fees (included in the cost of seed and difficult to estimate), 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 on U.S. and Canadian corn production.

Estimated 2025 Invertebrate Losses

In 2025, invertebrate pests reduced corn yield by an estimated 3.2 percent across 28 states and by 2.5 percent in Ontario, translating into an overall estimated loss of more than 554.6 million bushels. As in 2021, 2022, 2023, and 2024, corn rootworms were estimated to have caused the greatest yield loss overall (Figure 2). Estimated losses from all other invertebrates combined were 50 million bushels less than losses caused by corn rootworms. Other important invertebrate pests in terms of yield loss were western bean cutworm (Figure 3), corn earworm, grasshoppers, twospotted spider mite, and true armyworm. Table 1 summarizes yield-loss estimates for invertebrate pests affecting corn production in the U.S. and Canada; Figure 4 illustrates the proportions of yield loss for the most injurious pests.

Table 1. Estimated corn yield losses (thousands of bushels) due to invertebrate pests in 28 U.S. corn-producing states¹ and Ontario, Canada, in 2025.

¹ Alabama, Arkansas, Colorado, Delaware, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Louisiana, Maryland, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New York, North Carolina, North Dakota, Ohio, Oklahoma, South Carolina, South Dakota, Tennessee, Texas, Virginia, and Wisconsin; ² Diabrotica barberi, D. virgifera virgifera, D. undecimpunctata howardi, and D. virgifera zeae; ³ Chinavia hilaris, Euschistus spp., Halyomorpha halys, and Nezara viridula; ⁴ Nephelodes minians, Feltia jaculifera, Apamea devastator, Euxoa detersa, and Peridroma saucia. May also include Agrotis ipsilon (MD); ⁵ Popillia japonica (immature) and Phyllophaga spp.; ⁶ May also include cutworms in general (MD); ⁷ Rhopalosiphum padi, R. maidis, and Aphis protaphis middletonii; ⁸ Systena frontalis (SD), Meromyza americana (NE), and Dalbulus maidis (KS, LA, MO, OK, TX). The presence of D. maidis was noted in two states, but with no yield losses attributed to it (KS, LA); three states attributed losses to corn stunt, the disease vectored by this insect, but losses due to corn stunt are not included in this report (MO, OK, TX); ⁹ Colaspis brunnea and Colaspis crinicornis; ¹⁰ Chaetopsis massayla, Euxesta annonae, E. eluta, and E. stigmatias; ¹¹ Choristoneura parallela and Xenotemna pallorana.

Invertebrate Pests by Production Region

The states reporting data from the western corn-growing region accounted for 71.5 percent of U.S. and Ontario corn production. Corn rootworms caused the most injury in this region (Table 2), due to the high amount of intensive continuous corn and Bt-resistant rootworm populations. Western bean cutworm, corn earworm, grasshoppers, and twospotted spider mite caused the greatest estimated yield losses after corn rootworm.

The states reporting data from the Great Lakes region accounted for 17.5 percent of U.S. and Ontario corn production. As in the western region, corn rootworm caused the greatest estimated yield loss (Table 3); however, the next greatest causes of yield loss differ in the Great Lakes region. In descending order, grasshoppers, true armyworm, Asiatic garden beetle, and seedcorn maggot caused the next greatest losses. In this region, it is estimated that 1.3 percent of corn yield was lost due to invertebrate activity. 

The states reporting data for the southern region represented 8.3 percent of the total corn produced in the U.S. and Ontario in 2025. Overall, losses due to corn invertebrate pests across southern states were very low (0.9 percent) (Table 4) compared to the western corn-growing region (3.9 percent) in 2025. Stink bugs caused the greatest yield loss in the southern states, followed by southwestern corn borer, corn earworm, corn rootworms, and Banks grass mite.

Yield losses caused by insect-vectored diseases are generally not included in these reports. However, the authors wanted to convey the serious impact of corn stunt, a disease vectored by the corn leafhopper (Dalbulus maidis), in some U.S. states. Although not included in any tables or other data reported here, losses due to corn stunt were estimated to be 14.1 million bushels in Texas and 6.9 million bushels in Oklahoma. These losses indicate that the corn leafhopper, through the spread of pathogens causing corn stunt, was responsible for 4.6 times the next greatest cause of invertebrate pest losses (stink bugs) in the southern region. Missouri also experienced losses attributed to corn stunt, but to a much lesser extent (4,767 bushels).

Table 2. Estimated corn yield losses due to the five most-significant invertebrates in western corn-growing U.S. states¹, in 2025.

¹ Colorado, Illinois, Iowa, Kansas, Minnesota, Missouri, 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. and Ontario, Canada¹, in 2025.

¹ Indiana, Michigan, New York, Ohio, Wisconsin, and Ontario, Canada; 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 2025.

¹ Alabama, Arkansas, Delaware, Florida, Georgia, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, and Virginia; ² Chinavia hilaris, Euschistus spp., Halyomorpha halys, and Nezara viridula; ³ Diabrotica barberi, D. virgifera virgifera, D. undecimpunctata howardi, and D. virgifera zeae.

Disclaimer

The invertebrate pest loss estimates in this publication were provided primarily by extension specialists across the U.S. and 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 for comparing general trends across years or within a given year across regions. Values reported in this document were accurate as of the publication date and do not reflect corrections or updates occurring since that time.

Acknowledgements

Authors

Dominic Reisig, North Carolina State University; Scott Graham, Auburn University; Nick Bateman and Glenn Studebaker, University of Arkansas; Ron Meyer, Colorado State University; Francis Reay-Jones, Clemson University; Ken Wise, Cornell University; David Owens, University of Delaware; Isaac Esquivel, University of Florida; G. David Buntin, University of Georgia; Jocelyn Smith, University of Guelph; Nick Seiter, University of Illinois; Adam Sisson, Iowa State University; Anthony Zukoff, Kansas State University; Dawson Kerns, LSU AgCenter; Kelly Hamby, University of Maryland; Chris DiFonzo, Michigan State University; Fei Yang, University of Minnesota; Whitney Crow and Tyler Towles, Mississippi State University; Chase Floyd and Ivair Valmorbida, University of Missouri; Pin-Chu Lai and Julie Peterson, University of Nebraska; Patrick Beauzay and Janet Knodel, North Dakota State University; Ashleigh Faris, Oklahoma State University; Christian Krupke, Purdue University; Kelley Tilmon, Ohio State University; Tracey Baute, Ontario Ministry of Agriculture, Food and Agriculture; Adam Varenhorst, South Dakota State University; Sebe Brown, University of Tennessee; David Kerns and Pat Porter, Texas A&M University; Tim Bryant, Virginia Tech; and Emily Bick, University of Wisconsin-Madison.

Reviewers

Daren Mueller, Iowa State University and Kiersten Wise, University of Kentucky.

Production data from the United States Department of Agriculture-National Agriculture Statistics Service and Statistics Canada. 

United States Department of Agriculture National Agricultural Statistics Service. Quick Stats Database. Accessed 31 January 2026.

Statistics Canada. Table 32-10-0359-01. Estimated areas, yield, production, average farm price, and total farm value of principal field crops, in metric and imperial units. Accessed 20 January 2026.

Sponsors

In addition to support from the United States Department of Agriculture - National Institute of Food and Agriculture, this project was partly funded by the National Corn Growers Association and the Grain Farmers of Ontario through the Sustainable Canadian Agricultural Partnership (Sustainable CAP), a federal-provincial-territorial initiative.

How to cite: Reisig, D., Graham, S., Bateman, N., Studebaker, G., Meyer, R., Reay-Jones, F., Wise, K., Owens, D., Esquivel, I., Buntin, G. D., Smith, J., Seiter, N., Sisson, A., Zukoff, A., Kerns, D., Hamby, K., DiFonzo, C., Yang, F., Crow, W., Towles, T., Floyd, C., Valmorbida, I., Lai, P., Peterson, J., Beauzay, P., Knodel, J., Faris, A., Krupke, C., Tilmon, K., Baute, T., Varenhorst, A., Brown, S., Kerns, D., Porter, P., Bryant, T., Bick, E. 2026. Corn Invertebrate Loss Estimates from the United States and Ontario, Canada — 2025. Crop Protection Network. CPN-2019-25. doi.org/10.31274/cpn-20260309-0.