C.

Botanist and USDA employee Frank N. Meyer introduced a new variety of dwarf lemon from China to California in the 1930s. The “Meyer lemon,” as it was named, soon became popular for being sweeter and less acidic than regular lemons. But in 1956, the Department of Agriculture prohibited the Meyer lemon after the variety was discovered to host the tristeza virus, which can easily spread to other citrus plants through aphids. Inspectors in some California counties even went door to door, making sure Meyer lemon trees were destroyed. It was not until 1976, when an “improved” virus-free Meyer lemon plant was developed at the University of California at Riverside, that it regained popularity.