For years, many preferred etrogim from Corfu for the celebration of Sukkot because of the fear that the Erez Israel variety was from grafted trees and therefore invalid. The Erez Israel producers countered that the poor workers of Erez Israel are worthier and therefore their product superior to the Corfu antisemites who were responsible for pogroms and blood libels. Some countered that the Corfu etrogim were grafted, etc.