Young trees sustain the most severe damage, but trees of any size can be affected. Blue spruce trees are most commonly and most severely impacted. Rhizosphaera needle cast is the most common disease on spruce trees that is received in the Plant and Insect Diagnostic Clinic. Always read and follow the pesticide label according to manufacturer instructions. Brown needles have tiny, black fungal fruiting structures in rows on either side of the midvein on the underside of the needle. Again, if you apply fungicides for needle cast disease, we ask you to make one of those applications one month after your first application. In the following growing season, sporodochia produce more spores and continue the disease cycle. We sometimes see spruce needle rust or another secondary fungus, but those instances are few. Late in the second season or at the start of the third season sporodochia produce spores, resulting in the appearance of irregular, fuzzy black lines along both sides of needles. Infected needles typically fall from trees by the end of the third summer after infection, but may also fall earlier during the second season. Rhizosphaera needle cast is a fungal disease of spruce trees that causes needles to turn brown and fall off. Stigmina needle cast is often mistaken for Rhizosphaera needle cast. Rhizosphaera needle cast damage in spruce. Avoid planting susceptible spruce trees. Trees can be protected from Rhizosphaera needle cast with properly timed fungicide applications. This genus also infects several conifer species including; fir, cedar, spruce, and pine Signs and symptoms of Rhizosphaera needle cast Norway spruce is susceptible to a variety of diseases, but the two main ones are cytospora canker disease and Rhizosphaera needle cast. Norway, black, blue, and white spruce are hosts to this pathogen. Both diseases occur because of fungus growth on the trees, but each has different symptoms. Another common spruce tree disease is rhizosphaera needle cast. Labeled fungicides include products containing the active ingredients azoxystrobin, chlorothalonil, copper hydroxide, copper salts of fatty and resin acids, copper sulfate, mancozeb, mono- and di-potassium salts of phosphoric acid, pyraclostrobin, sulfur, and thiophanate-methyl. The recent pattern of milder than usual winters and cool spring temperatures combined with wet conditions in the northeast have favored development of a fungal disease known as "needle cast". Please see our website for current forms, fees, and instructions on collecting and packing samples. The Colorado blue spruce is the most susceptible spruce to this disease. Needles with signs (evidence) of the pathogen, Type of sample needed for diagnosis and confirmation. Rhizosphaera needle cast is caused by the fungus Rhizosphaera kalkhoffii. The Iowa State University Plant & Insect Diagnostic Clinic can help you to investigate and confirm if your plant has this disease. The fungus Rhizosphaera kalkhoffii causes needle cast of spruce. Spruce and coniferous trees are susceptible to environmental, insect and disease problems that can cause the trees to discolor, lose needles and possibly die. 2150 Beardshear Hall No fungicides are currently labeled in the United States specifically for stigmina needle cast, however, fungicides labeled for needle diseases of spruce trees may be used in the state where they are registered. Early detection and proper diagnosis is important in the treatment of… Now is a critical time to inspect spruce trees for Rhizosphaera needle cast, a common disease of spruce trees in Minnesota. Ames, IA 50011-2031 The most abundant spread of spores and infection within the canopy occurs in the first two months after budbreak, but spore production and infection can occur as long as temperatures are above 50 °F. Microscopic observation is required to distinguish both diseases from each other. Field identification is based on symptoms, but accurate identification requires laboratory analysis.Healthy spruce trees will retain 5 or more years of needles. Remove infected spruce trees means of preventing stigmina needle cast. If your sample is from outside of Iowa please do not submit it to the Plant & Insect Diagnostic Clinic without contacting us. The best evidence for needle cast are tiny black dots arranged in rows on infected needles. Contact information for each states diagnostic laboratory for U.S. residents. Norway spruce is relatively resistant. By late summer approximately one year after initial infection, entire needles or parts of infected needles appear darker and range from yellow to tan to brown or purple in coloration. Copyright © 2020ISU Extension and Outreach Early in the spring following initial infection, new spores are produced. (800) 262-3804, Iowa State University | PoliciesState & National Extension Partners, Like us at Plant and Insect Diagnostic Clinic, Like us at Department of Plant Pathology and Microbiology, Contact information for each states diagnostic laboratory for U.S. residents. It mostly occurs on spruces that are not being grown in their native habitat. Cytospora canker, needle cast, and rust diseases, mites, eastern Spruce gall adelgid, Cooley’s Spruce gall adelgid, bagworms, spruce budworm larvae, sawfly larvae, Reproductive System: Monoecious : Propagation: Through pollens : Wildlife Value: Cone scales are consumed by caterpillars, and barks are fed by moths : Cultivars: 1. Stigmina needle cast is often mistaken for Rhizosphaera needle cast. Use of fungicides is possible, but may only be sensible for larger-scale growers such as nurseries and Christmas tree farms. Microscopic observation is required to distinguish both diseases from each other. Acrocona 2. Rhizosphaera needle cast is most severe on Colorado blue spruce, with Norway spruce being resistant. In areas where stigmina needle cast is prevalent, the most effective management tactic is tree selection. This fungus infects the young growing needles of Colorado blue spruce, white spruce and Norway spruce. Needle casting disease of spruce is currently managed with fungicides after the new growth has expanded to 0.5 to 2.0 inches in length, typically in May. Stigmina needle cast is a fungal disease of spruce trees caused by the pathogen Stigmina lautii. Colorado and Engelmann spruce are very susceptible, but Norway and white spruce are somewhat resistant. Spruce trees can show brown needles starting from the lower limbs and progressing up the tree. Immature sporodochia, which are fungal fruiting bodies, develop on needles by late spring and overwinter. However, as 2017 was a banner year for the fungus, I commonly saw it on white spruce and even on Norway spruce, which is supposedly resistant to the disease. Stigmina needle blight: Year-old needles turn yellow, brown and then fall in the Spring a year after infection. Spruce Needle Cast Confusion; April 21, 2004: There is only one major needle cast disease to deal with in Illinois, Rhizosphaera needle cast. Symptoms progress over the course of 3 years, leading to needle discoloration and severe thinning of foliage on the lower two-thirds of trees. For rhizosphaera needle cast disease to take hold, needles … With needle cast, needles may look yellow by mid to late summer and turn brown or purplish brown by late winter or early spring. In both cases, sprays must occur yearly. White spruce is somewhat susceptible. Rhizosphaera needle cast is caused by fungal pathogens within the genus Rhizosphaera. Norway, black, blue, and white spruce … The first indications of disease appear as tiny black spots (sporodochia) on stomatal pits along with faint yellow bands around the needles. Trees stressed from drought, poor planting practices or other factors are more likely to suffer from Rhizosphaera needle cast. Stigmina needle cast is a fungal disease of spruce trees caused by the pathogen Stigmina lautii. Rhizosphaera needle cast disease is caused by the fungus Rhizosphaera kalkhoffii Bubak. White specks of wax from stomatal pits may be visible on top of the sporodochia at this stage. Some spruce trees, such as Colorado Blue Spruce may be susceptible to environmental stress. Spruce in both urban and rural landscapes can be affected. In this case, there are two options: (1) spray only during the first two months after bud-break to save only the youngest, most visible needles for aesthetic purposes, or (2) spray season-long to prevent infections entirely until the diseased needles fall off. Young and old needles are equally susceptible, but due to tree growth patterns new needles appear green and healthy while older needles will show more advanced stages of symptoms. White spruce is moderately resistant and Norway mostly resistant. Fruiting Bodies (sporodochia)- signs of the fungal pathogen. May 18, 2020.