Answer: Needle blight is a common fungal disease that causes browning of needles of Austrian, ponderosa, and mugo pines. Affected needles have reddish brown spots or bands. The needle tips beyond the bands dry out and turn brown a couple weeks after the bands appear, while the bases remain green. Diseased needles may drop prematurely, several months after they are infected. Typically, the most severely affected branches are towards the bottom of the tree. An entire tree may progressively lose its needles, decline, and die over the course of a few years.
Before spraying with a fungicide, you'll want to have a positive diagnosis of the problem. Take some of the affected needles into your cooperative extension office for inspection. If the problem is needle blight, fungicide sprays may be used. Sprays should be applied twice in the spring after new growth appears, once in mid-May and again 4 to 6 weeks later. Effective sprays include Bordeaux mixture and copper fungicides. Be sure to apply according to label directions.
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