Here is some info about Spider Mites from Wizzie Brown, Extension Program Specialist - Integrated Pest Management.
Spider mites are common plant pests that are found on the underside of leaves. Their feeding can cause leaves to discolor, causing a speckled appearance. With severe infestations, the plant leaves discolor to a silver or bronze color which may result in the leaves dropping from the plant.
Spider mites are arachnids, closely related to spiders and ticks. Similar to spiders, spider mites can produce silk and often cover leaves with web-bing, especially when there are large populations. The webbing helps to protect the mites and their eggs from natural enemies and harsh environ-mental conditions.