Wireworms
Egg - Newly laid eggs of the tobacco wireworm are spherical, white, and about 0.5 mm in diameter. Though undescribed, eggs of Conoderus lividus are probably similar.
Larva - Newly hatched larvae of the tobacco wireworm are white and approximately 1.5 mm long. Tobacco wireworms become cream colored and average 13 mm long when they mature. Full grown larvae of the species C. lividus average 24 mm. Both species have a tan to brown, V-shaped notch in their last abdominal segment. Color plate.
Pupa - The brown pupae are slightly larger than adults. They occur in the soil near the food source.
Host Plants - Although tobacco wireworm larvae prefer tobacco, they also attack corn, cotton, potato, bean, peanut, and various truck crops. The adult beetles commonly feed on the weed mullein. Conoderus lividus larvae are most frequently found in bluegrass sod or in fields which were in sod the previous year. C. lividus beetles, on the other hand, are commonly found on trees and shrubs, especially walnut and hickory.
Damage - Wireworm larvae damage peanuts by feeding in the seed, roots, underground stem and pods of the plant. Ragged holes are apparent in infested roots and stems. The above ground symptoms may include poor germination, chlorotic plants, and low productivity.
Life History - Since little is known concerning the life cycle of C. lividus, the following life history is based on the tobacco wireworm. About 240 eggs per female are laid singly on or slightly beneath the soil surface in summer. Larvae hatch and feed on the roots of tobacco, corn or other plants. The larvae overwinter 5 to 9 cm below the soil surface. If crop hosts are planted the following spring, these wireworms feed on the germinating seeds and young seedlings. Pupation then occurs in the soil, and adults emerge during early summer. There is only one generation per year. The average life cycle requires about 348 days, as follows: egg, 10 days; larva, 315 days; pupa, 10 days; and preoviposition period, 13 days.
