Adult raspberry horntails are sawflies, and their larvae feed inside the tops of raspberry canes, making them wilt over. Often, pruning out infested canes is...
Fruit
Fire blight is caused by a bacteria, and infections primarily start in open flowers.
Codling moth entry in a young apple fruit.
Syrphid fly larvae are maggots, ranging in color from yellow to olive green to bright green.
Syrphid flies are one of the first insect predators to see in spring. They look like bees, but you'll see that they just have one set of wings, like flies.
Lady beetle larva.
Lady beetle adults seek out their prey and lay clusters of bright yellow eggs.
Codling moth larvae feed on seeds inside the fruit.
Powdery mildew shows up on newer foliage first, and foliage may become yellowed and distorted.
This oozing is associated with shothole borer.
The oozing here is not caused by a disease. It is due to bark splitting from excess fruit load the prior year.
Pruning out cytospora is important. But this cut was made through the middle of a canker. You can see the ooze coming through the cut area.
Cutting out the diseased area is not always successful. The healthy bark may be damaged, or you may not get all of the cytospora, as shown here.