Wireworms

Various species

  1. Symptoms: Wireworm damage is very similar to that caused by other soil-inhabiting chewing insects; the only sure means of identifying wireworms as the causal agent is to find them in association with the damaged seedlings (picture at left). The name "wireworm" refers to the tough, wire-like appearance of the larvae. They are 20-30 mm long and are often smooth, hard, and highly polished. They have three pairs of legs (picture at right), and their color may vary from a rich cream to shades of brown.
    Wireworm larvae may attack wheat as soon as the crop is seeded, eating the endosperm of the kernels and leaving only the seed coat. A common sign of wireworm attack is the wilting and/or dying of a number of adjacent plants, either in a row or patch. The stems of affected seedlings will be chewed just above the seed.
  2. Life Cycle: Wireworms are the larvae of click beetles, of which there are many species. The adult beetles (picture below) lay eggs in the soil, usually in the spring, and the larvae may take several years to develop prior to pupating, depending on species. Generations overlap so that all stages and sizes of larvae may be found in the soil at the same time.
  3. Hosts/Distribution: Many species of wireworms are found throughout the world, all of which can attack wheat. These larvae are capable of attacking many different plant species as well.
  4. Importance: Wireworms are among the most damaging soil-infesting insects. Damage is usually most severe where wheat has been seeded after fallow or after a number of years of grass.

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