black canker vs luderick

black canker

noun
  • The larva of the turnip sawfly (Athalia rosae), an agricultural pest having the appearance of a black caterpillar. 

  • Any of several plant diseases causing the formation of dark cankers. 

luderick

noun
  • The fish Girella tricuspidata. 

How often have the words black canker and luderick occurred in a corpus of books? (source: Google Ngram Viewer )