If the tree is water-stressed during hot summer weather, fruit will be damaged and might drop prematurely from the tree. Late winter or early spring is the best time to prune apples and pears, but you can prune until mid-summer. Pruning later will stimulate new growth that probably will be damaged by early fall frosts. Mites and aphids can be serious problems. Mites causes damage to foliage and in some cases to fruit.
Aphids suck sap from apple and pear trees.
About two weeks after petal drop is the time to control the larvae of codling moths on apples. These pests infest fruit causing the familiar wormy apple. Spray every two weeks with diazinon or malathion to prevent this problem. Fireblight is spread by bees, as they visit the flowers. If you need to spray, use streptomycin sulfate and spray just when flower buds begin to turn pink, before they come all the way out.