The Collaborative International Dictionary of English v.0.48:

Wireworm \Wire"worm`\, n. (Zool.)
   (a) One of the larvae of various species of snapping beetles,
       or elaters; -- so called from their slenderness and the
       uncommon hardness of the integument. Wireworms are
       sometimes very destructive to the roots of plants. Called
       also wire grub.
   (b) A galleyworm.
       [1913 Webster]

WordNet (r) 3.0 (2006):

wireworm
    n 1: wormlike larva of various elaterid beetles; feeds on roots
         of many crop plants