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Lirula needle blight8/25/2023 ![]() We comply with the Federal Trade Commission 1998 Children’s Online Privacy Protection Act (COPPA). The 4-H Name and Emblem have special protections from Congress, protected by code 18 USC 707. Reference to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned. This information is for educational purposes only. Quentin Tyler, Director, MSU Extension, East Lansing, MI 48824. Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status or veteran status. MSU is an affirmative-action, equal-opportunity employer, committed to achieving excellence through a diverse workforce and inclusive culture that encourages all people to reach their full potential. When the spores are mature, a crack in the needle opens along this line. Photo: Jan Byrne, MSU. Spores are produced beneath the elongated, slightly raised, black line along the infected needles. Microscopic view of spore producing structure in the needle. For more information, visit the University of Minnesota Extension Lirula needle blight fact page. Protectant fungicides effective against other needlecast diseases such as chlorothalonil or mancozeb may provide control. Shear healthy trees first and disinfect tools often.Ĭurrently, no information is available on the effectiveness of fungicides for control of this disease.Promote good air movement by providing adequate spacing or controlling weeds.Avoid planting spruce where Lirula needle blight occurs.Inspect nursery stock for signs of infection.MSU Extension recommends following these general plant health guidelines: Not much is known about controlling Lirula. Spores are released from these structures on third year needles. On second year needles, you will find a raised black line, which is a spore producing structure on the midrib on the underside of the needle. The current year’s needles appear to be the most susceptible. In late spring through midsummer, infected needles release spores that spread by splashing and dripping rain to new needles. The fungus overwinters in infected needles on the tree. Lirula macrospora takes several years to complete its lifecycle. Unlike other needlecasts we find on spruce, the brown needles killed by Lirula can remain attached for several years. White spruce, including Black hills spruce, is a more susceptible species. ![]() Hosts include Colorado blue spruce ( Picea pungens), and white spruce ( Picea glauca). Lirula needle blight is caused by the fungus Lirula macrospora. In subsequent years, the needles stay attached but turn purple to gray. The following year, the infected needles develop a black line on them. These affected needles turn yellow or brown in late summer. Severely defoliated trees can lose nearly all of their >1-year-old needles, but associated tree mortality is rare.Recent samples of browning interior needles on Black hills spruce sent to Michigan State University Diagnostic Services found Lirula needle blight. Lirula needle blight is a fungal disease that first presents on two-year-old needle growth. Red-brown foliage discoloration and premature needle shed symptoms become apparent in late summer and fall, 1.5 years after infection. In spring (and summer if conditions are suitable), primarily infecting new needles. Spores are rain-splash dispersed from fruiting bodies Rhizosphaera: Small black fruiting structures occupy pores for gas exchange (stomata) on needles (generally requires a hand lens for identification). Trees compared to smaller trees in young-growth stands. Symptoms generally appear in older groups of adjacent needles. Lophodermium: Fruiting structures are black and elliptical, often with black zone lines crossing needles. Smaller trees are often more severely affected than large trees. Thinning and pruning trees to increaseĪir movement in the crown can reduce infection. Although usually not necessary, chemical control is effective when applied around bud break. One-year-old needles, and tan two-year-old needles, often interspersed with healthy foliage. This results in a distinctive pattern of green new growth, red-brown Red-brown foliage discoloration symptoms become apparent one year after infection, with needles turning tan-brown after two years. Spores are released from mature fruiting structures on infected two-year-old needles in spring to infect newly emerging foliageĭuring shoot elongation. Lirula: Fruiting structures are black and elongated on the undersides of needles. Rhizosphaera and Lirula needle casts are considered more damaging than Lophodermium needle cast in Alaska. Where persistent needle wetness promotes foliage disease. Symptoms are often most severe in the lower and interior tree crown, These diseases can be distinguished based on the fungal fruiting structures on needles, and (when severe) also on the pattern of foliage discoloration.
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