Agronomy Library

Product Selection for Above Ground Insect Larvae

Titan Pro
January 25, 2023

Insect larvae that feed on above ground corn tissue (stalks, leaves, ears) have the potential to decrease yield potential. Larvae that feed on stalks include European corn borer, southwestern corn borer, common stalk borer, and black cutworm (seedling plants). Foliage feeding larvae include European corn borer, fall armyworms, and black cutworm (seedlings). Ear feeding larvae include European corn borer, western bean cutworm, and corn earworm.

European corn borer has shown to reduce yield potential ranging from 6% loss/borer/plant in pre-tassel corn to 3% loss/borer/plant post pollination.1 Weakened stalks and ear shanks from European corn borer tunneling can cause lodging and ear drop (Figures 1 and 2). More common in southern states, southwestern corn borers tunnel into the stalk and girdle corn plants near the brace roots (Figure 2).

Figure 1. Tunnels in stalks from European corn borer larval feeding.


Figure 2. European corn borer feeding in ear shank (left) and southwestern corn borer damage at base of corn plant (right).

Corn earworm larvae feed on corn silks and developing kernels in the ear. Potential yield losses can be from a combination of direct kernel damage and reduced grain quality (Figure 3). Holes in husks resulting from earworm feeding can potentially be entry points for pathogens like Fusarium and Gibberella, which can produce mycotoxins.(2)

Figure 3. Corn earworm, feeding damage, and mold.

Insecticides are one way to help protect plants from insect feeding; however, application timing is critical to successful management. Corn products with Bacillus thuringiensis (B.t.) traits that control specific Lepidopteran pests offer long-lasting plant protection against crop injury. Several B.t. protection options are available including VT Double PRO® Technology which provides dual modes of action against specific above-ground larvae and Trecepta® Technology provides three modes of action to protect against key above-ground pests. (Table 1).

VT Double PRO® Technology provides protection against corn borers (European and southwestern), fall armyworm and corn earworm. Trecepta® Technology, which includes VT Double PRO® Technology and Vip3A, provides control for corn borers (European and southwestern), fall armyworm, corn earworm, western bean cutworm, and black cutworm.

Selecting Products

Corn products should be selected for a particular field based on a combination of agronomic characteristics that include disease tolerance, standability, adaptability to soil type, drought tolerance, yield potential, end use, and a trait package that helps protect yield potential. VT Double PRO® corn products and Trecepta® corn products are available to help protect corn plants from key above-ground pests; however, they do not have B.t. protection for corn rootworm (CRW). Therefore, these products should be used where CRW pressure is not a concern. In areas with CRW pressure, products with SmartStax® or SmartStax® PRO Technologies should be selected.

Article Link

1Potter, B. 2020. European corn borer in Minnesota field corn. University of Minnesota Extension. https://extension.
2Tilmon, K., Paul, P., and Michel, A. 2018. Corn earworm making an unpleasant late-season appearance; watch for molds. C.O.R.N. Newsletter. 2018-32. Agronomic Crops Network. The Ohio State University Extension.
Websites verified 9/9/22.
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ALWAYS READ AND FOLLOW PESTICIDE LABEL DIRECTIONS. B.t. products may not yet be registered in all states. Check with your seed brand representative for the registration status in your state.
IMPORTANT IRM INFORMATION: RIB Complete® corn blend products do not require the planting of a structured refuge except in the Cotton-Growing Area where corn earworm is a significant pest. See the IRM/Grower Guide for additional information. Always read and follow IRM requirements.
Performance may vary, from location to location and from year to year, as local growing, soil and weather condi-tions may vary. Growers should evaluate data from multiple locations and years whenever possible and should consider the impacts of these conditions on the grower’s fields.
Roundup Ready® 2 Technology contains genes that confer tolerance to glyphosate. Glyphosate will kill crops that are not tolerant to glyphosate. Insect control technology provided by Vip3A is utilized under license from Syngenta Crop Protection AG. Herculex® is a registered trademark of Dow AgroSciences LLC. Agrisure Viptera® is a registered trademark of a Syngenta group company. LibertyLink® and the Water Droplet Design® is a trademark of BASF Corporation. Respect the Refuge and Corn Design® and Respect the Refuge® are registered trademarks of National Corn Growers Association. Bayer, Bayer Cross, RIB Complete®, Roundup Ready 2 Technology and Design™, Roundup Ready®, SmartStax®, Trecepta® and VT Double PRO® are trademarks of Bayer Group. ©2022 Bayer Group. All rights reserved. 1219_51731