Feeding mites have a dark spot on either side of the body which may enlarge to cover most of the body. Overwintering females are orange, and hibernate under bark scales on the tree and in trash on the ground. They move up the tree in late March and April, feeding on leaves. Rapid reproduction occurs in hot, dry weather and the infestation peaks in July and August.
Heavy infestations result in severe bronzing of foliage and premature defoliation.
Fruits on heavily infested trees fail to color and size properly and fruit production for the following year may be lowered. Predator mites have been developed that are resistant to carbaryl and most organophosphates used in apples. One predator to 10 webspinning mites is necessary for the predators to keep control of the pest mites. Use lower rates of miticides to minimize destruction of predators and allow some spider mites to survive. The apple rust mite is an alternative food source for the predator mite.