![]() ![]() This discoloration is frequently restricted to particular annual increment of foliage. The most conspicuous symptoms of needle blights are red, yellow or brown discoloured needles, which may later turn grey. ![]() the "sexual" fruiting body, which is generally large, occurs along the mid-ribs of the lower needle surface e.g., Lirula punctata. the "asexual", which occurs like small dots on the upper surface of the needles, e.g., Lirula punctata.Ģ. Generally two types of fruiting bodies develop during the life cycle of blight fungi:ġ. Lower branches and understory trees are frequently the most seriously blighted as the more humid conditions favor infections.Įconomic damage caused by the needle blights is conjectural. ![]() Blights are more common following wet springs. Isthmiella quadrispora causes damages on 2-year old infected needles.Ĭlimatic conditions influence spore dissemination and germination, and thus the frequency and severity of infection. The degree of damage can be influenced by the age of the host tree older trees are more resistant to damage and infection of older needles is eventually harmless. Heavily infected trees have an unsightly appearance caused by needle discolouration. Seedlings may be severely damaged if a high percentage of the foliage is infected. Only a few of the many blight diseases in British Columbia are known to cause serious damage which is limited to increment loss tree mortality is not known. Severe infection can result in significant growth reduction. Needle and shoot blights are caused by a related group of fungi (Ascomycetes), which cause more damage to coniferous foliage in North America than any other group of fungi. When transplanting trees, always allow for adequate spacing to promote air circulation and to help reduce infection.This blight is widely distributed throughout the range of its hosts in the interior regions of British Columbia. During drought conditions, consider a combination of watering deeply, mulching to moderate soil temperature, and properly fertilizing to optimize nutrients. Repeat the application during the wet season, when environmental conditions are conducive for fungal development. Treatment includes pruning severely affected branches and disposing of fallen needles, followed by applying an appropriate fungicide in spring. With proper treatment, there is hope for conifers infected by this fungal pathogen. This disease can be difficult to control. Trees that lose first-year needles for several consecutive years appear thin, lose lower branches, and may eventually die. Between 15 and 18 months after infection, needles typically begin to drop. As fungi mature, rows of black fruiting bodies may appear on needles. Infected needles of other plant species typically become off-green before turning tan or brown. One of the earliest symptoms of rhizosphaera needle cast in Colorado spruce is mottled-yellow needles that progressively turn bright yellow, then purplish-pink and eventually brown. How to Identify Rhizosphaera Needle Cast: Other conifer hosts include deodar cedar, douglas fir, true firs, hemlocks, pines and coast redwood. Many types of spruce are very susceptible to rhizosphaera needle cast, including Colorado spruce and Engelmann spruce. However, this fungal infection can affect conifers anytime during the growing season. Cool, rainy weather and long periods of leaf wetness make this a common spring condition. Rhizosphaera is a fungal genus that affects cone-bearing shrubs and trees throughout the Northern hemisphere. ![]()
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