![]() The fungus produces a toxin that quickly kills the tissue at the infection site and causes it to turn purplish red, giving this disease its common name, red-band needle blight. Next, yellow to tan spots become visible and then eventually change to become larger, reddish-brown lesions banding the needle (Figure 2). This symptom occurs briefly and is usually not detected. In late summer, infected needles may show dark green bands that look water soaked. Courtesy of Tracey Olson, PDAĪfter infection takes place, symptoms are not visible for 3–6 months on average. Infection from cast needles on the ground below the tree is negligible.įigure 1. Current-year needles are not susceptible until they have elongated and hardened off, usually around July. Second-year or older needles are susceptible to infection throughout the season. The spores are spread by wind and splashing rain and enter healthy needles through the stomata. Beginning in May, spores are released from dark brown or black fruiting bodies that rupture through the epidermis of previously infected needles (Figure 1). Red-band needle blight infection occurs throughout the growing season during wet periods. The fruiting bodies are visible in the diseased area with a hand lens and are typically covered by a flap of needle epidermis. Eventually, tiny, dark brown or black fruiting bodies are produced and release spores. Only the base of the needle will be green, with the remaining portion tan or brown. ![]() Although initial symptoms include dark green bands on the needles, these are quickly replaced with brown or reddish brown lesions. This disease, also referred to as Dothistroma needle blight, is called red-band needle blight because of the most common symptom found in the field.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |