Brown spot needle blightīrown spot needle blight ( Mycosphaerella dearnessii, syn. Repeat the application two or three times as needed at seven- to 10-day intervals. This year (2013), you might start earlier since trees are ahead of normal. To protect foliage from infection, apply a registered fungicide containing copper or mancozeb in mid-June through mid-July. The best protection of new needles can occur when applying copper-based materials 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. The 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. Photo credit: Jill O’Donnell, MSU Extension Needle tips turning brown on Austrian pine. These spots enlarge to form distinct brown to reddish-brown bands. The main symptom is dead needle tips beyond the yellow to tan needle spots. Recently, we have also found Dothistroma on white pine. This common pine pathogen kills needles of all ages and can weaken or kill Austrian pine trees. Dothistroma needle blightĭothistroma needle blight is caused by the fungus Mycosphaerella pini Rostr. Symptoms of these diseases are very similar and knowing the tree species and when you are seeing the symptoms can help you identify which one you may have. For Christmas tree plantations and highly valued ornamental trees, the use of fungicides may be necessary.The two most common needle blights Michigan State University Extension educators and specialists find on pines in Christmas tree plantations are Dothistroma and brown spot needle blights. Remove and dispose of all infected material, including needles on the ground if practical. In late summer, fall and into the following spring, black fruiting bodies can be seen with noticeable tearing of the needle epidermis.Infected needles commonly have dead brown tips, yellow and brown bands and green bases.Yellow and tan spots appear early in the summer, later coalescing into brown bands with yellow halos encircling the needle by late summer and fall.Damage is first noticeable in the lower branches.Branches look bare from accelerated 2 nd and 3 rd year needle losses with only tufts of current year needles remaining.Brown or reddish brown needles that drop prematurely are characteristic of this disease.In late summer and into the fall fruiting bodies form on infected needles in the tree and on the ground.Most infections occur in late spring and can take several months for symptoms to appear needle tip browning and spots begin to develop over the summer and into the fall.Warm wet weather is required for spores to germinate and penetrate healthy needles.Disease overwinters on dead infected needles remaining on the tree and on the ground and is spread though spores distributed by wind, rain splash and contaminated equipment. Scots ( Pinus sylvestris) and Austrian pine ( Pinus nigra) are most commonly affected, but all pine species are susceptible to infection. The disease seldom kills trees but can cause significant defoliation on 2- and 3-year-old needles with current year needles also being infected in severe disease years.Most damaging on low branches and small trees.The disease causes brown needle spots, needle browning, and needle drop.
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