potato bug vs sai bug

potato bug

noun
  • Any of various insects that feed on or harm potato plants. 

  • The Colorado beetle or Colorado potato bug (Leptinotarsa decemlineata). 

  • The Jerusalem cricket, various insects of the genus Stenopelmatus. 

  • The striped blister beetle or old-fashioned potato bug (Epicauta vittata). 

  • The woodlouse, various terrestrial crustaceans of suborder Oniscidea. 

sai bug

How often have the words potato bug and sai bug occurred in a corpus of books? (source: Google Ngram Viewer )