Malus sieversii apples supposedly have a MUCH wider range of flavors than domesticated apples, and are very disease and pest resistant. One of my goals is to establish a dozen or or more of the better-tasting Malus sieversii trees on my farm. Getting hold of them is incredibly difficult, but I keep trying.
Look into the spray-free apple series from Jung’s. Liberty, Enterprise and Freedom.
They’ve got to have some of those Malus sieversii qualities bred into them. I have Liberty and it is a fantastic producer with NO bug issues. (I’ve never spray any of our apple/fruit trees).
Beau has planted those three (twice!) on the edge of one of our deer food plots, but even with protection, the deer keep eating them before they can even produce. Of course, they leave the mature, wild apple trees in the pasture alone!
Truly an exercise in futility.