The Collaborative International Dictionary of English v.0.48:

San Jos'e scale \San Jo*s['e]" scale\
   A very destructive scale insect (Aspidiotus perniciosus)
   that infests the apple, pear, and other fruit trees. So
   called because first introduced into the United States at San
   Jos['e], California.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

San Jose scale
    n 1: small east Asian insect naturalized in the United States
         that damages fruit trees [syn: San Jose scale,
         Aspidiotus perniciosus]