![]() ![]() This spring's new growth is initially resistant to infection and will not become susceptible until midsummer, around July. The second application, which protects the current season's new growth, is made after considerable new growth has taken place, usually around mid June. The first application should be done in mid May, and protects the existing needles from infection. Read and follow all label directions carefully before application. Infection of susceptible needles can be significantly reduced with liquid (Tenn-Cop 5E or Black Leaf Liquid Copper Fungicide) or fixed copper formulations (Basic copper sulfate or Tribasic Copper Sulfate) or with Bordeaux mixture applied twice during the growing season. Symptoms appear about three to four months after the first infection, usually becoming visible in late fall. Germinating spores enter the needles through natural openings and the infection process begins. Initial infection of the tree by fungal spores occurs during rainy periods from May to October. As the spots enlarge, the entire needle turns. Usually the greatest amount of needle drop is seen in the late spring or early summer following infection. In March and April, brown spots or bands with yellow haloes appear on the previous years needles. Lower branches of trees are most severely infected although the entire tree can be affected. Typically, clusters of needles within a shoot are infected. Initially, the tip of the needle dies while the base remains green, but eventually as the disease progresses, the base of the needle also dies, and the entire needle drops off the tree. The fungus grows within these tissues, killing that portion of the needle beyond the lesion. These bands are often bordered by a yellow, chlorotic ring on each side. These spots darken and become brown or reddish-brown then spread to form a band around the needle. Yellow or tan spots appear on needles of the current year's or older growth. ![]() Scotch pine is usually not severely damaged. Twenty pine species are affected by this disease, but in the central and eastern United States the fungus is found most commonly found on, and causes the greatest amount of damage, to Austrian and Ponderosa pine. This disease is responsible for much of the premature needle drop that occurs in windbreaks and ornamental pine plantings. One of the most common fungal diseases of pines in Nebraska is Dothistroma needle blight. My Austrian pine tree has a lot of brown needles. ![]()
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