It would be difficult to imagine what could have changed two common pathogens at the same time to become more aggressive on the same trees; that is not a probable option at this point. The canker grows slowly, eventually circling and killing a twig or branch. Both Phomopsis and Diplodia are known as pathogens of various species of conifer trees and they can kill branches. For more information, visit Colorado blue spruce is particularly susceptible and can be severly damaged by this disease. Dr. Fulbright's work is funded in part by MSU's AgBioResearch. Close up of lower branches on the 2011-photographed tree showing the total involvement of the lower branches. It was not immediately apparent what was causing these symptoms. Natural Areas Conservation Training Program, Black walnut toxicity (plants tolerant of), Preventing construction damage to trees and shrubs, Trees and shrubs for the four seasons landscape, Sudden Oak Death, Ramorum Blight and Phytophthora ramorum, Eastern United States Wetlands Collection. The disease has progressed from the lower branches up to about the lower third of the tree. piceae), is the most prevalent and destructive fungal disease of Norway and Colorado blue spruce. You can search, browse, and learn more about the plants in our living collections by visiting our BRAHMS website. What could be uniformly stressing these trees across the Lower Peninsula such that so many spruce trees are afflicted with the stress pathogens? Close examination of those needles will show rows of tiny black dots (you may need a hand lens to see these), which are the fungal fruiting structures that produce the spores of the fungus. To have a digest of information delivered straight to your email inbox, visit Two weeks ago we first reported on a severe decline of spruce trees throughout Michigan (see Spruce problems are probably caused by more than a single agent). Spores are dispersed by splashing rain, wind, sprinklers, pruning tools, and possibly by movement of insects and birds. Sometimes infection will start on branches in the middle of a tree, creating defoliation “holes” among healthy branches. July 29, 2011. The rows of black stomata are a diagnostic feature of Rhizosphaera needle cast. Stop by, email, or call. So, it is plausible that the death of the branches and trees can occur via continuous re-infection by needle-loving pathogens. We have been receiving more contacts from people noticing the spruce decline around the state. Reference to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned. Photo 1. Photo 5. Jeffrey W. Dwyer, Director, MSU Extension, East Lansing, MI 48824. The spores of Rhizosphaera needle cast are released from spring until fall; thus, working near trees in wet weather should be avoided throughout the growing season. This time the photo was taken in mid- July 2011. Check out the MSU Sports & Commercial Turf Management Certificate Program! Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status or veteran status. Thirty-year-old Colorado blue spruce tree photographed in 2009. Use up and down arrow keys to explore within a submenu. Minimize stress of established trees by taking care not to injure the root system or compacting the surrounding soil. Symptoms spread upward and around the tree. But upon closer inspection (Photo 3), there are sections of needlecast and branch death around the base of the tree that are beginning to become noticeable, hence the reason the photos were taken in 2009. The following menu has 3 levels. Thirty-year-old Colorado blue spruce tree photographed in 2009. From a distance, the tree looks healthy with vigorous growth. West aspect of tree. The former option would be the best for the wallet and environment, but can we find the stress? Other hosts include white, black, Engelmann, Sitka, and Serbian spruce; Austrian, mugo, Eastern white, and Japanese red and black pine, as well as Douglas-fir and Siberian fir. In Photos 1 and 2, you can see a Colorado blue spruce from its east and west aspects in July 2009. Within the cankered area, black, pinhead-size fruiting structures (pycnidia) of the fungus can be seen with a microscope or hand lens and are a positive sign of the disease. Use enter to activate. Photo 2. Cytospora canker rarely affects trees less than 15 to 20 years old. Our trees. Use left and right arrow keys to navigate between menus and submenus. In moist conditions, the fungus inside older needles produces black fruiting structures (pycnidia) that appear as distinct rows of black, pinhead-size dots. Like Cytospera, this fungus is also spread during wet weather and may also infect Serbian spruce, mugo, and white pines. Use a three-to-four-inch layer of organic mulch to retain moisture and reduce rapid soil temperature fluctuations. On severely infected trees, the fungus will enter the trunk through wounds (usually where the branch meets the trunk of the tree), killing the cambium layer and leaving dead bark. Chemical control is not useful in controlling this disease. A third fungus has also been isolated from the branches, but identification will take at least another week. Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. At first, needles have a purplish hue, eventually turning brown and dropping, leaving dry, brittle twigs and branches. MSU is an affirmative-action, equal-opportunity employer. This disease can be frustrating because severe defoliation can occur quite rapidly and without indication that the disease is even present. This dead tissue is called a “canker.” A conspicuous white resin or “pitch” covers the cankered portion of the branch or trunk, sometimes flowing several feet down the trunk of the tree. A close up view (Photo 6) shows discolored needles, branches devoid of previous years’ needles (needlecasting), and dead branches.