Apple rust mite is an important secondary pest of apple which is much more troublesome if its key natural enemy, the orchard predatory mite Typhlodromus pyri, is not present.
A similar species, the pear rust mite, Epitrimerus piri, is frequently an important pest of pear. Pear trees have smooth, hairless leaves and less prominent leaf veins than apple. They do not favour predatory mites, which are not present in significant numbers in commercial pear orchards. Outbreaks of pear rust mite are frequent on pear, almost an annual event, for this reason.