Austrian pines are very susceptible to both this disease and another disease, Diplodia tip blight, such that they are not a good choice for this area. The best way to avoid Dothistroma needle blight in Iowa is to avoid planting Austrian pine.
#Bronze spot needle blight free#
If you are uncertain about the type of sample feel free to contact us.ĭothistroma on the needles of an Austrian Pine Branches can be packed into a box with paper towel for shipping. Samples should include symptomatic needles, living and still attached to a branch. To confirm Dothistroma needle blight we need to examine a sample under the microscope. If your sample is from outside of Iowa please do not submit it to the Plant & Insect Diagnostic Clinic without contacting us Contact information for each states diagnostic laboratory for U.S.
Please see our website for current forms and fees. The Iowa State University Plant & Insect Diagnostic Clinic can help you to investigate and confirm if you plant has this disease.
Type of Sample Needed for Diagnosis and Confirmation However, symptoms typically first appear in early fall, although they may not be noticed immediately. The fungus is active throughout the growing season and can infect any age of needle during wet weather. An entire tree may progressively lose its needles, decline, and die over the course of a few years.ĭothistroma needle blight is caused by the fungus Dothistroma pini (also called Mycosphaerella pini). Typically, the most severely affected branches are towards the bottom of the tree. Diseased needles may drop prematurely, several months after they are infected. The needle tips beyond the bands dry out and turn brown a couple weeks after the bands appear, while the bases remain green. Affected needles have reddish brown spots or bands.
Symptoms of Dothistroma needle blightĭothistroma needle blight is a common fungal disease that causes browning of needles of Austrian, ponderosa, and mugo pines. Fungicide sprays may be used if symptoms are found and are applied in the spring.ĭothistroma needle blight is especially common on Austrian pines.Dothistroma needle blight can be prevented by keeping trees in good vigor through watering and mulching, and promoting air circulation through appropriate pruning, adequate spacing, and weeding. Avoid planting the highly susceptible Austrian pine.Symptoms are similar to brown spot needle blight, but Dothistroma occurs primarily on Austrian and ponderosa pine and brown spot is more common on Scots pine.Infection usually occurs first on the lower branches of the tree and spreads upward.Brown bands will appear on infected needles and the portion beyond the band will die.
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