Today, these genetic similarities mean arabica coffee plants are more likely to be hurt by diseases like coffee leaf rust, which causes costly losses every year.
Because certainly by the early 1900s, like everybody understood that potatoes could get blight from spores going through the air and Wheat could get stem rust from the air.
And if you go to today to a coffee farm, the farmer will usually talk to you a lot about the need to increase water use sufficiency to fight diseases like coffee leaf rust, or coffee borer beetle.