Wireworms are common soil-dwelling pests that hinder plant establishment and reduce crop quality in gardens and agriculture. These subterranean larvae cause noticeable damage, affecting overall plant health and yield.
What Are Wireworms?
Wireworms are the larval stage of click beetles (Family Elateridae), named for the clicking sound adult beetles make when righting themselves. These larvae are slender, cylindrical, and hard-bodied. Their color ranges from yellow to reddish-brown, giving them a wire-like appearance. They measure 0.25 to 1.5 inches long.
The wireworm life cycle takes two to six years to complete a single generation. Most of this time is spent as larvae, living underground and feeding on plant roots and seeds. Adult female click beetles lay eggs in the soil, especially in grassy or weedy areas. Eggs hatch into larvae, which remain in the top six inches of soil, though they can burrow deeper in dry conditions. Larvae overwinter, and a field may contain multiple generations simultaneously.
How Wireworms Harm Your Plants
Wireworms damage plants by feeding on underground parts, consuming germinating seeds, roots, tubers, and stems. This feeding reduces seed viability or prevents germination, leading to poor stands. Early season damage appears as wilted or stunted seedlings, as wireworms bore into crowns or root systems, cutting off nutrient and water supply.
For root crops like potatoes, carrots, onions, and beets, wireworm damage is problematic. They bore holes and create tunnels within tubers and roots, rendering produce unmarketable. Damage appears as small, round holes on the surface, leading to narrow tunnels within the flesh. While adult click beetles do not cause plant damage, larval feeding can lead to economic losses in various crops including corn, wheat, beans, and other vegetables.
Effective Wireworm Management
Managing wireworm infestations involves cultural practices and direct control methods to reduce populations and minimize plant damage. Early detection is important; monitoring can be done by digging soil samples or using bait traps with germinating seeds.
Crop rotation is a key strategy, as wireworms favor crops like grasses and cereals. Avoiding susceptible crops like potatoes or corn in the same area for consecutive seasons, especially after grass or pasture, disrupts their life cycle and reduces populations. Including non-host crops like alfalfa, clover, mustard, or legumes in rotation decreases wireworm numbers over time.
Soil cultivation, such as tilling or plowing, exposes wireworms to predators like birds and unfavorable environmental conditions, disrupting their habitat. Fall tilling is effective in eliminating overwintering larvae. Soil solarization involves covering soil with clear or black plastic sheeting to heat it, raising soil temperatures to lethal levels.
Proper watering and drainage are important, as wireworms prefer moist, cool, heavy soils. Controlling grassy weeds around planting areas reduces egg-laying sites for adult click beetles. Planting seeds when soil temperatures are warmer speeds up germination, allowing plants to establish quickly and reducing vulnerability to wireworm feeding. Trap cropping, using plants like mustard, radish, or rye, lures wireworms away from desired crops. After attracting pests, these trap crops can be removed and destroyed.