Mites, fungus both causes of spruce needle loss

Q. I have nine spruce trees in my yard, all about the same height and age. I'm guessing them to be 40 to 45 years old. Seven are seemingly healthy, but two have me concerned because there appears to be a lot of dying needles on the interior of the trees, and their color overall seems dull to me. These trees are alongside my driveway, and get more water than the others, although they have good drainage. They get a great amount of sunshine throughout the day. Do you have any suggestions on what could be affecting these trees, and what I need to do to bring them back?A. It is normal for almost all evergreens to go through a shedding period every year in late summer and early fall. However, excessive needle loss may be cause by various needle diseases. Spruce mites cause devastating damage to the beautiful Blue Spruce and Colorado Green Spruce. Damage begins as dull green or browning interior needles. Mites multiply by the thousands every 10 to 17 days. If conditions are favorable, (cool, damp spring weather), they rapidly build throughout the summer. The fungus Rhizosphaera kalkhoffiican also causes the spruce to lose needles. Infection occurs in the spring usually on lower branches and works upward around the tree. Sometimes the disease may start higher and then work downward. Any size tree may be attacked but small trees are more susceptible and are more likely to be killed by serious yearly infection. Infected foliage usually turns a mottled yellow in late summer on current year needles. During the late winter and early spring, the needles turn brown and then fall off during the summer and fall leaving current year needles.Since there are other noninfectious diseases that may mimic needle cast symptoms, it is important to get positive identification of the disease. Take several branches to a reputable nursery, or #160;the University of Illinois Extension office at the Friendship Park Conservatory. The phone number is (847) 298-3502.bull; Provided by Mary Boldan, Mary Moisand and Donna Siemro, University of Illinois Extension Master Gardeners. Send questions to Ask a Master Gardener, c/o Friendship Park Conservatory, 395 W. Algonquin Road, Des Plaines, IL 60016, (847) 298-3502 or via e-mail to cookcountymg.com@gmail.com.