Life Cycle: The larvae overwinter in the soil and become active when soil temperatures reach 55 degrees. Adult females emerge, mate and burrow back into the soil to lay eggs. They can reemerge and go to other sites in the field to lay eggs. The egg laying soil preference can vary from light well drained soils to low spots where moisture levels are higher and clay is present. This often results in ‘hot spot' infestations in the field.
Damage: The wireworms feed on the developing roots of a seedling or a germinating seed. The seedling often dies before emergence or wilts shortly after emergence. Heavy damage can occur in spots in the field requiring replanting of that area.
Economic Thresholds: See the scouting method below.
Scouting Method: Soil sampling (digging for the wireworm) is required to determine if wire worm is present. NDSU suggests when digging soil samples, 12 or more wireworms in 50 ‘3-inch by 3-inch' samples, is likely to result in damage.
Management: There are excellent insecticide seed treatments available that will eliminate wire worm damage. Most seed companies now sell only treated seed with Cruiser® or Idol® primarily for wireworm control.
Research: This is not a research priority since excellent seed treatments are available.
Photos: Visit the Photo Gallery.
Another resource about Insects can be found in the Archive section of The Sunflower magazine.