![]() Photo credit: Jan Byrne, MSU Diagnostic Services. Several fungicide products with chlorothalonil, mancozeb or copper are labeled for control. In rainy conditions, the spray interval may need to be shortened. Needle spots can appear on needles at any time of the year, but most commonly we find them during August and September when the tree suddenly turns brown just before harvest.īottom of Scotch pine trees browning in August-September.Įven though we see the symptoms in the fall, fungicide applications should be timed when the new needles are about half grown (May-June) and a second spray about three weeks later. Scirrhia acicola) is relatively new to Scotch pine in Michigan. 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. 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.
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