Spider MitesSpider mites are very small arachnids which feed on the underside of leaves.  They cause a stippling damage pattern. Leaf discoloration and eventual leaf death occurs. Under favorable conditions, the spider mite can increase in numbers very quickly. Miticides must be applied as needed for management of this pest. Many landscape plants are vulnerable to activity of certain mites. Common hosts are hemlock, spruce (especially Alberta spruce) burning bush, forsythia, azaleas, and many other species.