In 1911, the avocado was a relatively new crop in Southern California and the great USDA plant explorer Wilson Popenoe (pronounced POP e Noe according to Jack Shepherd), describes avocado culture and its problems

https://www.biodiversitylibrary.org/item/137628#page/31/mode/thumb

This is from the first volume ever of the Pomona Journal of Economic Botany which also has a nice description of "wither tip" of citrus in Santa Paula.

https://www.biodiversitylibrary.org/item/137628#page/5/mode/1up