Corn Invertebrate Loss Estimates from the United States and Ontario, Canada — 2024

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 effect on yield is based on many factors, including weather conditions, crop production practices, and hybrid selection and susceptibility to invertebrate feeding.

The U.S. produced almost 14.9 billion bushels of corn in 2024, while the province of Ontario, Canada produced nearly 0.4 billion bushels. Extension specialists representing 29 corn-producing U.S. states and Ontario, Canada, estimated the percent yield loss from corn invertebrate pests. These reports account for more than 15.0 billion bushels (98.7 percent) of the total corn produced in the U.S. and Ontario in 2024 (Figure 1). The yield loss estimates include foliar, root, ear, and stalk feeding invertebrate pests. Yield loss estimates are not inclusive of diseases transmitted by invertebrates. Estimates are mostly for grain corn but can also include popcorn and sweetcorn. Data from Florida and Oklahoma were added in 2024.

This publication documents the impact of major invertebrate pests on corn production during 2024. 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 have expenses to control invertebrate pests of corn in the form of technology fees (included in the cost of seed and not easy 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 2024 Invertebrate Losses

In 2024, invertebrate pests reduced corn yield by an estimated 4.0 percent across 29 states and by 1.3 percent in Ontario, translating into an overall estimated loss of more than 610 million bushels. As in 2021, 2022, and 2023, corn rootworms were estimated to have caused the greatest yield loss overall. Estimated losses from all other invertebrates combined were 82 million bushels less than losses caused by corn rootworms. Other important invertebrate pests in terms of yield loss were western bean cutworm, corn earworm (Figure 2), twospotted spider mite, Banks grass mite, and grasshoppers. Table 1 summarizes yield loss estimates for invertebrate pests reported in corn production in the U.S. and Canada; Figure 3 illustrates the proportion of yield loss for the most injurious pests.

Table 1. Estimated corn yield losses (thousands of bushels) due to invertebrate pests in 29 U.S. corn-producing states¹ and Ontario, Canada in 2024.

¹ Alabama, Arkansas, Colorado, Delaware, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, 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 May also include cutworms in general (DE, MD); ⁴ Chinavia hilaris, Euschistus spp., Halyomorpha halys, and Nezara viridula; ⁵ Rhopalosiphum padi, R. maidis, and Aphis protaphis middletonii; ⁶ Popillia japonica (immature) and Phyllophaga spp.; ⁷ Dalbulus maidis (KS). Other states (OK, TX) recorded this insect but attributed losses to corn stunt, the disease vectored by this insect; ⁸ Nephelodes minians, Feltia jaculifera, Apamea devastator, Euxoa detersa, and Peridroma saucia. May also include Agrotis ipsilon (MD); ⁹ Choristoneura parallela and Xenotemna pallorana; ¹⁰ Overall a mix of species (FL); ¹¹ Chaetopsis massayla, Euxesta annonae, E. eluta, and E. stigmatias; and ¹² Colaspis brunnea and Colaspis crinicornis.

Invertebrate Pests by Production Region

The states reporting data from the western corn-growing region accounted for 72.2 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-resistant rootworm populations. Western bean cutworm, corn earworms, and mites caused the greatest estimated yield losses after corn rootworm.

The states reporting data from the Great Lakes region accounted for 19.0 percent of corn production in the U.S. and Ontario. Like the western region, corn rootworm caused the greatest estimated yield loss (Table 3); however, the next greatest causes of yield losses differ entirely in the Great Lakes region. In descending order, slugs, Asiatic garden beetle, black cutworm, and true armyworm caused the next greatest losses. In this region, it is estimated that 1.6 percent of corn yield was lost due to invertebrate activity.

The states reporting data for the southern region represented 7.5 percent of the total corn produced in the U.S. and Ontario in 2024. Overall, losses due to corn invertebrate pests across southern states were very low (1.1 percent) (Table 4) compared to the western corn-growing region (4.8 percent) in 2024. Twospotted spider mite caused the greatest yield loss in the southern states, followed by stink bugs, Banks grass mite, corn rootworms, and southwestern corn borer.

Table 2. Estimated corn yield losses due to the five most-significant invertebrates in western corn-growing U.S. states¹ in 2024.

¹ Colorado, Illinois, Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, and South Dakota; and 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 2024.

¹ Indiana, Michigan, New York, Ohio, Wisconsin, and Ontario, Canada; and 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 2024.

¹ Alabama, Arkansas, Delaware, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, and Virginia; ² Chinavia hilaris, Euschistus spp., Halyomorpha halys, and Nezara viridula; and 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 to compare general trends across years or regions within a given year. Values reported in this document were accurate as of the publication date and do not reflect corrections or updates occurring since that time.

Acknowledgments

Data Compilation

Dominic Reisig, North Carolina State University and Adam Sisson, Iowa State University.

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; Raul Villanueva, University of Kentucky; 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, 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 19 January 2024.

Statistics Canada. Table 32-10-0042-01. Estimated areas, yield, production of corn for grain and soybeans, using genetically modified seed, in metric and imperial units. Accessed 19 January 2024.

Sponsors

In addition to support from 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.