Symptoms of pine tree diseases develop from a variety of problems, such as fungal infection. From yellowing of leaves and complete defoliation, to visible physical changes and death of plant parts, symptoms provide a wealth of information that allows you to key in on the underlying disease affecting your pine tree. Always follow care requirements to keep trees vigorous and able to fight illness.
Symptoms of the disease needle casts include yellowing or browning of pine tree needles during which they take on the appearance of being scorched by heat. Needles may also be "cast" from the tree (fall to the ground). Symptoms first appear late in the autumn season after black fungal spots develop, spread spores and cause needle color change. While pine trees usually only suffer a patchy appearance due to large areas of missing pine needles, this disease can lead to tree death. Though more than 40 different fungi are responsible for needle casts, the most prevalent culprits include Hypoderma hedgcockii, Hypoderma lethale and Lophodermium pinastri, according to the Oklahoma Cooperative Extension Service. For control, remove and destroy diseased needles; additionally, fungicide application controls needle casts, but must be conducted by a professional when needles have reached half of their growth potential and again when they are full size.
Dothistroma Needle Blight
Symptoms of dothistromia needle blight include early defoliation when needles drop from the pine tree as well as overall diminished vigor. During the autumn season, light brown or yellow marks may appear on the tree as well as what appear to be bands of water on pine needles. Both of these types of spots may transition into a red-brown hue with yellow borders and needle tips will die, potentially breaking off. These symptoms are caused by fungal infection that spreads sporadically from the markings that form on trees. For control, collect and destroy affected plant parts. Also, apply copper fungicides in two separate treatments. For the first treatment, apply halfway through the month of May and apply the second coat in the middle of June, as suggested by the Oklahoma Cooperative Extension Service.
Diplodia Tip Blight
Diplodia tip blight symptoms include the decline of cone scales and rot just below the soil line on younger pine trees. Branch dieback is prevalent among more established pines, stunting the normal growth patterns of pine needles; needles change from green to a brown color and extreme resin counts emerge from buds. Also present on more mature trees are black fungal growths that inhabit the surfaces of pine cone scales. When this fungal infection enters pine trees through cracks and wounds, there is no control for younger trees. For more established trees, however, prune affected areas and destroy collected plant parts. Apply a copper fungicide in the beginning of the spring season at bud break and two additional treatments spaced one week apart in application, according to the Oklahoma Cooperative Extension Service.