Wireworms may not be one of the leading corn pests, but where they are present, they can cause significant stand losses. Wireworms are the larvae of click beetles and live in soils across North America, especially in corn-growing regions.1 Their soil-dwelling lifestyle makes them difficult to detect before damage occurs, and once established, they can reduce stands, yield potential and profitability. Effective management requires correct identification, scouting and integration of cultural and chemical strategies.
Wireworm identification
Wireworms look just like their name sounds. They are slender, hard-bodied larvae ranging from ½ to 1 ½ inches long, with a cylindrical, segmented body and reddish-brown color. They have three pairs of short legs near the head.
Adult click beetles are long and narrow with a distinct separation between thorax segments. When flipped on their backs, they snap themselves upright, creating a clicking noise. Eggs are tiny, white and spherical, and are typically deposited near the roots of grasses in spring.
The first year of infestation usually causes little noticeable damage. However, because click beetles can remain in the larval stage for four to seven years, economic damage often increases as infestations progress.2
Scouting and sampling strategies for wireworms in corn
Fields following sod, pasture or small grains are more prone to wireworm activity. Scouting before planting can help estimate risk.
- Option 1: Use a bait trap
Place untreated corn and wheat seed 6 inches deep and cover with black plastic to encourage feeding. After 7–10 days, inspect for larvae. Finding one or more per trap signals potential risk.3
- Option 2: With no bait trap
Dig 1-square-foot sections to a 6-inch depth in five field locations about ten days before planting. This method is labor-intensive and less reliable but may reveal heavy infestations.4
Wireworm damage in corn
Wireworms feed on germinating seeds, hollowing them out before emergence or burrowing into underground stems and roots of seedlings. Symptoms include reduced stands, wilted plants or seedlings that never emerge. Injury often occurs in patches, creating uneven stands. Because symptoms resemble seedling blight or nutrient stress, confirmation through scouting is critical.5
Damage is more likely to occur when corn is planted early and in colder environmental conditions that slow germination. Wireworms also appear in well-drained soils or on ridges and hilltops.
Wireworm control in corn
Controlling wireworms needs to be done proactively and preventively. Little can be done once an infestation is damaging your corn. Here are a few things you can do to get ahead of these pests:
Tillage practices
Shallow tillage before planting may expose larvae and eggs to predators or harsh conditions. While not sufficient alone, it can reduce pressure.
Seed treatments
Neonicotinoid seed treatments are commonly used, but they often do little to specifically control wireworms. However, Teraxxa® is the only seed treatment formulated to rapidly eliminate wireworms across all species and developmental stages, reducing pressure from the start.
Avoid sod and grasses
Infestations are more common in fields that were previously sod or grass. Rotating away from grasses lowers risk.
Apply Nurizma
Most foliar insecticides are ineffective against soil-dwelling pests. Nurizma® applied in-furrow helps manage wireworms as well as other below-ground pests such as corn rootworm larvae, white grubs and seedcorn maggots. Its novel mode of action and low use rate make it a valuable tool for broad-spectrum soil insect control.
The majority of wireworm infestations tend to be small and localized, and not worth excessive intervention. That said, it is always a good idea to proactively manage threats from pests that have the potential to minimize crop yields.
Experts are available to help you make your crop protection decisions. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative.
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Endnotes
- Gill, Harsimran K., et al. Corn Wireworm: Melanotus communis Gyllenhal (Insecta: Coleoptera: Elateridae). University of Florida IFAS, 2024, edis.ifas.ufl.edu/publication/IN1025.
- “Wireworms in Corn.” Purdue University Department of Entomology & Purdue Extension, Field Crops IPM, Purdue University, ag.purdue.edu/department/entm/extension/field-crops-ipm/corn/wireworms.html.
- “Wireworms in Corn.”
- “Wireworms in Corn.”
- “Wireworms and Corn.” Extension, University of Minnesota, 2018, extension.umn.edu/corn-pest-management/wireworms-and-corn
