The rapid decline of many spruce trees in Michigan and surrounding states appears to be related to an increase of canker diseases coupled with other disease and insect problems that plague the species. Spruce spider mites. The most common needle problem of blue spruce in Maryland is a fungal disease caused by Rhizosphaeria kalkoffii.. The most common disease of blue spruce is Rhizosphaera needle cast, a fungal disease that usually requires fungicides for management when it occurs. When severe, limbs over the entire tree can be affected. Needlecasts. Use left and right arrow keys to navigate between menus and submenus. 2. For some disease issues, such as needlecasts, fungicides may be effective in preventing or controlling the disease. Right, Needle damage caused by mites. Check out the MSU Fruit and Vegetable Crop Management Certificate Program! Diplodia kills needles at the tips of branches Symptoms often start on the lower half of the tree and progress upwards. However, a recent survey by Michigan State University researchers suggests two other fungal pathogens, Diplodia and Phomopsis, were much more commonly associated with branch death and tree decline than Cytospora (Photos 8-9). The fungus kills current year shoots and sometimes branches, and can disfigure or even kill them under severe conditions. As lateral shoots are killed, whole branches may die back to the trunk and the tree becomes disfigured. 2. I have read about the Needle Cast problem. Needle Cast or Needle Blight. Left, Gall caused by Cooley spruce adelgid. READ LABEL INSTRUCTIONS ON CONTAINER FOR DILUTION RATES AND METHODS OF APPLICATION. However, if pine shoot moth larvae cause the damage, either the larvae or its tunnel will be found inside the shoot. Tiny spores called conidia erupt from the pycnidia in wet weather. Diplodia and Phomopsis are both considered weak or secondary pathogens, so it is unclear at this point why they appear to cause major disease problems for spruce. When we see diseases in blue spruce, which is not often, it usually is one of two different types--Cytospora C Middle, New shoot tips killed by Phomopsis tip blight. ), and junipers (Juniperus spp.). Austrian pine (Pinus nigra) is the most susceptible host, although the following pines are also susceptible: Scots pine (Pinus sylvestris), red pine (Pinus resinosa), Mugo pine (Pinus mugo), Ponderosa pine (Pinus ponderosa) and occasionally Eastern white pine (Pinus strobus). Explore this online platform for Chicago-area residents to share their favorite stories about trees. This article was published by Michigan State University Extension. This distinction is important since not all insecticides will control mites. Reference to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned. As with any tree health problem, the first step in dealing with declining spruce trees is to diagnose the problem and identify the cause. The user is responsible for determining that the intended use is consistent with the label of the product being used. Damage from gall adelgids is mainly aesthetic. Building the urban forest for 2050. Check out the MSU Landscape and Nursery Management Certificate Program! 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. Keep the tree watered during dry periods. After the needles have fully expanded, the shoot can no longer be infected by the fungus. Trees may produce ridges of wound tissue around older canker infections as the tree attempts to restrict the fungus’ growth. Maintain tree health because the disease is more severe on trees that are under stress. The needles begin to die several weeks after infection. The following menu has 3 levels. Also, in many cases there may be more than one issue that is affecting your tree’s health. Some locations have an additional infection period in September and October. As they do so, they cause the shoots to deform and produce galls that resemble cones (Photo 6). Maintain a layer of mulch under the tree to conserve moisture. Use up and down arrow keys to explore within a submenu. Blue spruces are a favorite conifer of Iowans and several reasons. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464). 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. Douglas-fir, white, Norway, and blue spruce may also be infected, but infection of these species usually develops only on trees that are injured or stressed and when infected pine … Tip blight is very common in the blue atlas cedar during humid or wet weather. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. Adelgids are small insects that feed on shoots by sucking plant sap. Because the fungus can also infect wounded tissues, avoid pruning trees from late spring to early summer when they are most susceptible. This is a difficult question. June 28, 2019. Right, Resin oozing from a branch canker caused by Cytospora. Generally all needles on the current season’s shoot are killed.Often resin droplets are seen on the dead shoots. White spruce is somewhat susceptible. Eastern red cedar, creeping and Rocky Mountain junipers, arborvitae, Douglas-fir, true firs, larch and jack pine are most commonly affected by the disease. Canker diseases. It is important to note that fungicide treatments for needlecasts only protect new growth. As the name implies, trees with needlecast diseases shed needles. When the conidia land on a susceptible plant part, they infect it by penetrating the plant through wounds or stomates, usually in mid- to late spring. Tip blights are fungal diseases that typically cause dieback to new, emerging shoots (Photo 4). In landscapes, Colorado blue spruces have been planted on some sites that are marginal for their success. Colorado blue spruce trees have long been among the most popular conifers for landscaping in Michigan and the upper Midwest. Canker diseases are caused by fungi that infect branches or the main stem of trees. Key site factors for blue spruce trees are full sunlight, good air movement and excellent soil drainage. As a result, trees affected by needlecasts often have an outer “shell” of live needles on current shoots and dead needles on older shoots (Photo 3). Bert Cregg, Christine McTavish, Andrew Jarosz, Jill O'Donnell, and Dennis Fulbright Michigan State University - Photo credits: Jill O’Donnell, MSU. Wind and rain disseminate the conidia. Symptoms: On the lower branches, yellowing of first-year needles in mid-summer on 8-15 year-old trees. Lirula needle blight can infect white spruce (Picea glauca), including Black Hills spruce and Colorado blue spruce (Picea pungens). Tip blights. Tip blights are fungal diseases that typically cause dieback to new, emerging shoots (Photo 4). Tip blights. In wet seasons it is not uncommon to see the branches of the entire tree show browning tips. In both cases, the insect pests are tiny and you may need a hand lens to see them. Michigan’s climate is generally more humid, especially in the summer, which is ideal for fungal pathogens to thrive. For large or important landscape trees, homeowners should contact a professional arborist or tree care company. When the new needles (candles) are expanding, they become stunted, turn yellow, and then turn tan or brown. Alternative conifers for Michigan landscapes. Later in fall after the needles have died, the pycnidia appear on the base of the needles or on second year seed cones. The most common needle problem of blue spruce in Maryland is a fungal disease caused by Rhizosphaeria kalkoffii.. Our trees. Numerous insect pests can impact spruces in Michigan’s landscape, but the two most common are gall adelgids and spruce spider mites. Photos 3-5. In addition to being a beautiful tree that maintains color year round, these trees make an excellent wind break and for the most part grow quite well here. Inner needles first become discolored … A fungus called Diplodia pinea causes the disease. In fact, it is not uncommon to see healthy, thriving spruce trees near or adjacent to trees that are in severe decline. ; Then the needles turn brown, or sometimes purplish brown, before they defoliate through the late summer into fall. Blue spruce trees are widely planted due to their good growth rate, stately form and, of course, their blue foliage. 2. Needlecast fungi often infect needles on the current year’s shoots. Douglas-fir, white, Norway, and blue spruce may also be infected, but infection of these species usually develops only on trees that are injured or stressed and when infected … Candles can only be infected by the fungus while they are elongating in the spring. 1. 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