![]() Brown spot needle blightīrown spot needle blight ( Mycosphaerella dearnessii, syn. Dead needle tips and needle base remains green. Reports suggest that pruning infected branches helps reduce disease. The best protection of new needles can occur when applying copper-based fungicides as the new needles emerge from the needle sheaths and as the spores are released from the fruiting bodies. ![]() The black fruit bodies appear in the fall however, the spores are released the following spring and summer. New needles are susceptible once they emerge from the needle sheaths. Dothistroma spores spread by wind and rain and can infect needles throughout the growing season. The black fruiting bodies of the fungus can be seen in the dead spots or bands on the needles. Characteristic symptoms of Dothistroma infection is the presence of needles showing browning at the tip of the needle while the base of the needle remains green. This common pine pathogen kills needles of all ages and can weaken or kill Austrian pine trees. The foliage of the lower half of the tree turns brown in March to April.ĭothistroma needle blight is caused by the fungus Mycosphaerella pini. Dothistroma needle blightĪustrian pine is commonly affected by Dothistroma needle blight. In addition, several possible fungal pathogens can cause these symptoms as well. Winter burn occurs frequently on dwarf Alberta spruce but can occur on other conifers as well. In some cases, trees will have a snowline below which no damage occurs since those needles were under snow when the rest of the tree was drying. The most common symptom of winter burn is brown or red foliage on the exposed (often south) side of the tree. Many conifers are subject to needle drying of winter burn during the winter. Sensitive trees such as white pine can usually survive one-year’s damage but repeated acute damage can ultimately disfigure or kill trees.Īnother culprit is winter injury. Acute damage caused by direct salt exposure is easy to spot since the damage is usually greatest on the side of the trees facing the road. Many plants, especially eastern white pine, are sensitive to salt spray from roadways. Road crews apply sodium chloride and other deicing materials to keep roads clear in the winter. Photo by Bert Cregg, Michigan State University.Ĭonifers located along the road can be damaged by road salt. Environmental – related issues Road salt damage on white pine. Photo by Bert Cregg, Michigan State University. Pine identification left to right: Scots (Scotch) pine, Austrian pine, eastern white pine. Older Scots pines have orange-reddish bark, whereas the bark on Austrian pines is grey. Scots pines have shorter (1 1/2'” or less) needles and smaller cones than Austrian pines. Hard pines have two or three needles in each fascicle. Austrian pine and Scots pines are part of group known as hard pines along with our native jack pine and red pine. ![]() White pines have long (4” or longer), slender cones. The needles are thin and soft and often pale green. White pines have five needles in each fascicle. Determining the number of needles in a fascicle is the first step in identifying pines. Unlike many other conifers, needles on pine trees are clustered together in groups called fascicles. The most common pines in residential and commercial landscapes in Michigan are eastern white pine, Austrian pine and Scots (or Scotch) pine. Depending on the type of pine tree, there are several common causes of needle browning in pines. As spring arrives, we begin to see browning of pine needles in plantations, landscapes and along roadsides.
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