Brown spot needle blight treatment6/23/2023 ![]() ![]() Quentin Tyler, Director, MSU Extension, East Lansing, MI 48824. Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. 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. MSU is an affirmative-action, equal-opportunity employer, committed to achieving excellence through a diverse workforce and inclusive culture that encourages all people to reach their full potential. Shear healthy plantations first so pathogen spores will not be carried into them from affected plantations.Sterilize tools after shearing affected plantations by dipping in denatured alcohol for three minutes.Do not shear infected trees during wet weather because spores released at this time may be carried from tree to tree, on workers’ clothes or shearing tools. ![]() Michigan State University Extension advises adjusting your shearing practices to avoid moving spores into other plantations: Photo by Jan Byrne, MSU Diagnostic Services. Several products with chlorothalonil or mancozeb are labeled for control.īlack fruiting bodies on dead needles. Shorten the spray interval in rainy conditions. Apply the first application when the new needles are about half-grown (May-June) and a second spray three to four weeks later. Brown spot can be controlled by fungicidal sprays. Short-needled Scots pine varieties such as Spanish and French-green are more susceptible to fungal attack than the long-needled varieties. On brown needles, you will find numerous black fruiting bodies. If you look closely at last year’s foliage, you will find reddish-brown, resin-soaked spots with yellow margin on green needles. These can appear on needles at any time of the year, but most commonly during August and September on Scots pine. The fungus causes two kinds of needle spots. On trees that have been severely infected, only the very top of the tree may still be green. The symptoms of brown spot needle blight infection are now beginning to show up in Scots pine Christmas trees. Scirrhia acicola) was first reported in Michigan in the fall of 2010. Brown spot needle blight ( Mycosphaerella dearnessii, syn. ![]()
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