Although I have not received any reports of problems with European red mites in apples, now is the time when growers should be scouting for infestations. Most growers know where mite problems show up first, either a particular variety (i.e, Red Delicious) or along a gravel road. Check those spots first and expand your scouting if you find them. The spray thresholds change through the season, so check my publication at https://extension.entm.purdue.edu/publications/E-258/E-258.html to determine if you need to spray. These thresholds are based both on the susceptibility of the trees to losses and on the need to stop increasing populations of mites early so that they don’t get out of hand. As you are choosing miticides to apply, consider rotating between several modes of action, even between years. We currently have a number of effective miticides and if we use them properly, we should have good control materials for many years to come.