Wireworms are the larval stage of click beetles (family Elateridae) and are common insects found in agricultural fields and gardens. People frequently encounter these larvae when digging in the soil, leading to concerns about potential danger to human health. While wireworms are a nuisance to crops, they pose minimal direct health risks to people. This article explores the minimal direct health risks associated with the larvae and their broader role as an agricultural pest.
Direct Human Health Risks
Wireworms pose no direct threat to human health. They are subterranean feeders on plant material and possess no mechanisms for defending themselves against humans. The larvae do not have stingers, venom, or toxins that could cause harm through contact.
Their mouthparts are adapted for chewing plant roots and seeds, not for biting mammalian skin. Wireworms are also not known to transmit human pathogens or diseases. The only minor risk is temporary physical irritation from handling the larvae, as their hard, segmented bodies may cause a mild skin reaction in sensitive individuals.
Identifying Wireworms and Their Life Cycle
Wireworms are easily recognizable due to their distinct appearance. The larvae are slender, segmented, and hard-bodied, resembling a piece of stiff wire. They typically range from yellow to yellowish-brown and grow to be between one-half and one and a half inches long when mature.
The larval stage is the most prolonged part of their existence, often lasting between two and six years. Adult click beetles lay small, white eggs in the soil, often preferring grassy or weedy areas. Because the larvae live underground for an extended period, they move deeper during dry or hot periods and closer to the surface to feed when conditions are cooler and moist.
Primary Role as Agricultural and Garden Pests
The harm associated with wireworms is economic and agricultural, not medical. The larvae are generalist feeders, consuming the roots, shoots, and seeds of plants. They cause damage by boring into newly planted seeds, hollowing out the germ and preventing germination, which leads to gaps in crop rows.
Wireworms also tunnel directly into underground crops like potatoes, carrots, onions, and sweet potatoes, making the produce unmarketable. In young corn and cereal crops, the larvae will shred the underground portion of the stem or cut off small roots, causing the seedlings to wilt and become stunted. It is this destructive feeding habit on high-value crops that causes them to be a significant concern for commercial farmers and home gardeners alike.