The most effective pollinators for apple trees are other apple trees of a different variety, particularly those that bloom at the same time as the tree that needs pollination. This is because apple trees are not self-fertile, meaning they require pollen from a different variety of apple tree in order to produce fruit.
In addition to other apple trees, other fruit trees such as pear, crabapple, and quince can also act as good pollinators for apple trees. Honeybees, bumblebees, and other types of bees are also important pollinators for apple trees, as well as other insects such as flies and beetles. It’s important to ensure that there are enough pollinators present in the orchard to ensure proper pollination and fruit set.