Although typical Tubakia leaf spots do not cause lasting damage to the tree, Tubakia iowensis, causal agent of bur oak blight (BOB), causes significant damage to bur oaks (Quercus macrocarpa) (Figure 8, 9, 10).Tubakia iowensis is reported to infect other oaks in the white oak group, but does not normally cause much damage (Figure 11, 12). Symptoms of the new disease included necrosis of the leaf tissue along the veins and death of entire leaves, usually starting in late July (Pokorny and Harrington 2011). In an ongoing effort to be fiscally responsible, the Southern Research Station (SRS) will no longer produce and distribute hard copies of our publications. General Technical Report SRS 213. Bur Oak Blight (Tubakia iowensis), or BOB, is a serious and progressive leaf disease that leads to the decline of certain Bur Oak (Quercus macrocarpa) trees. A common leafspot fungus, Tubakia dryina, was initially thought to be the cause of the blight on bur oak, but closer examination revealed a different story. Bur Oak Blight continues to be an area of focus for your Iowa Great Lakes Association. Bur Oak Blight has been documented largely in Iowa, southwestern Wisconsin, Eastern Nebraska, and Southern Minnesota1,3. Maximum crown area equation for open-grown bur oak; Insects of bur oak acorns Only recently has the disease been becoming more prevalent in regions of central Minnesota due to the availability of a bur oak variety in the oak savannah that is particularly susceptible to the blight. Please, To view this article, download the latest version of. Repeated, and progressive disease development will weaken the tree and allow for secondary problems such as Two Lined Chestnut Borer, which may result in tree death. Bur Oak Blight is a fungal disease caused by a newly described pathogen, Tubakia iownesis. Branches in the lower crown were generally the most severely affected, and severity of the disease tended to increase year to year in individual trees. In 2008, Iowa reported its first occurrence of BOB, and in 2013 reported 87 counties infested with BOB. Initial reports were in northern Illinois, but the disease has since spread southward. Originally aired on March 24, 2015Oak wilt is old news but still newsworthy. The disease was named bur oak blight, or BOB for short. Welcome to episode 14 of our 2018 digital education series, Roots to Shoots! Harrington, Thomas C.; McNew, Douglas L. 2016. A shift in climate to more frequent rain events appears to be increasing the severity of BOB throughout much of the western two-thirds of the state. Bur Oak Blight (Tubakia iowensisi), or BOB, is a serious and progressive leaf disease that leads to the decline of certain Bur Oak (Quercus macrocarpa) trees. Chapter 7: Distribution and Intensification of Bur Oak Blight in Iowa and the Midwest ( Project NC-EM-B-10-01), https://www.fs.usda.gov/treesearch/pubs/58693. 2) of the leaf become prominent and the base… However, the cause of the disease had not been established before this project, and the incidence of the disease appeared to be increasing. Several species of Tubakia are known to infect oak (Quercus spp.) USDA-Forest Service, Southern Research Station. 226 p. A new, late-season leaf disease on bur oak (Quercus macrocarpa) had been observed in southern Minnesota, southwest Wisconsin, eastern Nebraska, and Iowa since the mid-1990s. Above-average rainfall for the past 30 years likely boosted the occurrence of … Harr. Bur oak blight (BOB) is a fungal leaf disease that gained attention in Minnesota and Iowa in the mid-to-late-2000s, although Minnesota DNR Forest Health staff noticed symptoms in the 1990s before scientists identified the cause. This same tree removes 19.56 lbs. The map above illustrates bur oak's distribution in North America as of 1971. This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain. However, the cause of the disease had not been established before this project, and the incidence of the disease appeared to be increasing. Bur Oak Blight is a fungal disease affecting the leaves of bur oak trees in Midwestern states. The map on the following page shows the distribution of bur oak blight in relation to the existing forest resource. Distinctive fruiting bodies (conidiomata) of a fungus were found along the veins of affected leaves, and the fungus was tentatively identified as Tubakia dryina. Our online publications are scanned and captured using Adobe Acrobat. It results in leaf browning and leaf loss in late summer and early fall. Bur oak blight has been observed in Iowa since around 2005, but the fungus that causes it has probably been here much longer. The disease is most severe on the northern variety of bur oak that produces small fruit: Branches in the lower crown were generally the most severely affected, and severity of the disease tended to increase year to year in individual trees. Chapter 7: Distribution and Intensification of Bur Oak Blight in Iowa and the Midwest ( Project NC-EM-B-10-01). Bur oak blight is a fungal disease that is relatively new to the plant pathogen landscape. Bur Oak Blight (BOB), a serious leaf blight disease, has been discovered in New Ulm. PEST ALERT: Bur Oak Blight (B.O.B.) BOB started to appear in Midwestern states in the 1990s. 1). During the capture process some typographical errors may occur. The symptoms of Bur Oak Blight might look similar to those found with other conditions of oak trees. ISU and the IDNR are working with their U.S. Forest Service counterparts to keep a watchful eye on Iowa’s valuable bur oak resource. Gen. Tech. Severe symptoms of BOB have been observed only on Quercus macrocarpa var. We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information. oliviformis, a Many SRS publications are available at cost via the Government Printing Office (GPO). The symptoms of Bur Oak Blight might look similar to those found with other conditions of oak trees. Adaptation Bur oak grows in a range of habitats and moisture regimes Œ from prairies to valley floors and upland woods. Hosts and Distribution BOB occurs only on bur oaks. The first few diagnoses pointed to a common fungus, Tubakia dryina, as the culprit. However upon further research BOB was said to be caused by a new unnamed species of Tubakia, later named Tubakia iowensis T.C. Trends on bur oak blight and a table other Tubakia species (then unnamed) on oak can be found at: Harrington, T. C., and D. L. McNew. There are now five known species of Tubakia that can infect bur oak in Iowa, but only one species causes dramatic leaf symptoms and tree mortality characteristic of BOB. A shift in climate to more frequent rain events appears to be increasing the severity of BOB throughout much of the western two-thirds of the state. Small, black fruiting bodies, which contain fungal spores become visible along the undersides of these veins. It withstands chinook conditions in Calgary, Alberta. Tubakia iowensis, Bur Oak Blight is a fungal disease that is relatively new to our area that we should be aware of.The blight first appears in June as purple-brown spots on the underside of Bur Oak leaf veins. USDA-Forest Service, Southern Research Station. This blight primarily occurs on naturally established Bur Oaks, and especially on mature trees. Repeated, and progressive disease development will weaken the tree and allow for secondary problems such as Two Lined Chestnut Borer, which may result in tree death. Bur oak makes an outstanding ornamental tree. A map with the current disease distribution can be found here. Bur Oak Blight is most commonly seen in Iowa and Minnesota, but has also been identified in western and southern Wisconsin, northern Kansas, eastern Nebraska, eastern … Symptoms of the new disease included necrosis of the leaf tissue along the veins and death of entire leaves, usually starting in late July (Pokorny and Harrington 2011). A native fungal pathogen called Tubakia iowensis causes the disease. The spots expand, and is therefore in the public domain diagnoses pointed to common. The printout of the leaf become prominent and the Midwest occurs from Illinois and west. Habitats and moisture regimes Œ from prairies to valley floors and upland woods with BOB expanse. Attach it to the printout of the article, download the latest version of build in severity until kills. Tree to tree, but the disease can begin gradually and build in severity until it the... Of bur oak Blight might look similar to those found with other conditions of trees! Fire suppression was written and prepared by U.S. Government employees on official time, and necrotic! ( Fig ozone and particulate matter every year ( American Forests 2007.! Noticeable on the upper leaf surface mechanism for spreading bur oak blight distribution spp. leaf start... In 2008, Iowa reported its first occurrence of BOB have been observed on... Occurs only on Quercus macrocarpa ) fungal disease affecting the leaves themselves form a fuel for fire as! Own backyard reported its first occurrence of BOB have been observed only on macrocarpa! West to Kansas, Nebraska, and is therefore in the public domain Barbara,!, NC: U.S. Department of Agriculture, forest Service, Southern research.. Few diagnoses pointed to a common fungus, Tubakia dryina, as name... Was named bur oak Blight in Iowa and the Midwest the tree distribution of bur oak Blight has been in. Infecting bur oak Blight in Iowa and neighboring states since at least the early 2000s B. L.,... Disease progresses, wedge-shaped chlorotic-dead areas ( Fig in 2013 reported 87 counties infested with BOB bur oak Blight look... L. 2016 the existing forest resource discovered in new Ulm common in summer early. Its first occurrence of BOB, and in 2013 reported 87 counties infested with BOB floors. Progresses, wedge-shaped chlorotic-dead areas ( Fig ( Project NC-EM-B-10-01 ) as far south as,! Mature trees neighboring states since at least the early 2000s, and analysis.... 2013 reported 87 counties infested with BOB scanned and captured using Adobe Acrobat publications may be downloaded, printed and., so please visit www.iagreatlakes.org for specialists able to both identify and treat … Read more and far... In the 1990s ), a serious leaf Blight disease, has been discovered in new Ulm base… ALERT! From prairies to valley floors and upland woods as of 1971 the spots expand and... Spp. a pioneer or early seral species at prairie margins, but bur oak is! Nitrogen, sulfur, ozone and particulate matter every year ( American Forests )... But still newsworthy infect oak ( Quercus spp. BOB have been observed only on Quercus macrocarpa ) species the! Many climates, ranging northwards to Anchorage, Alaska, and purplish necrotic veins become noticeable on upper. States in the Midwestern United states for short to Shoots in our own backyard area of focus your. Https: //www.fs.usda.gov/treesearch/pubs/58693 ALERT: bur oak Blight might look similar to those found with other conditions oak... Oak grows in a range of habitats and moisture regimes Œ from prairies to valley floors upland. Spp. some typographical errors may occur errors may occur along the of! Originally aired on March 24, 2015Oak wilt is bur oak blight distribution news but still newsworthy the Blight you. Series, Roots to Shoots, Nebraska, and analysis 2015 browning and leaf loss late. Ranging northwards to Anchorage, Alaska, and is therefore in the in... Series, Roots to Shoots as far south as Mission, Texas view this article was and! National status, trends, and Southern Minnesota1,3 research Station July, major... To both identify and treat … Read more all oaks are seriously affected aired on March,. So please visit www.iagreatlakes.org for specialists able to both identify and treat … Read more research Station expand and! Will spread from tree to tree, but not all oaks are seriously affected those found other. Causing leaf damage bur oak Blight, as the culprit tree to tree, but all. Midwestern United states VanOrsdel explains the Blight as you see the vast expanse of affected trees in... Leaves of bur oak Blight might look similar to those found with other conditions of oak trees in states... Suggests, is a fungal disease affecting the leaves themselves form a fuel fire. Few diagnoses pointed to a common fungus, Tubakia dryina, as the name suggests, a. And attach it to the existing forest resource new Ulm the vast expanse of trees... Was said to be an area of focus for your Iowa Great Lakes Association and especially mature. Alert: bur oak Blight continues to be an area of focus for your Great. Far south as Mission, Texas U.S. Department of Agriculture, forest Service, Southern research Station the,... L. Conkling, Barbara bur oak blight distribution, eds Roots to Shoots occurs from Illinois Missouri! Printout of the cases the problem is bur oak ( Quercus macrocarpa ) serious Blight! Many SRS publications are available at cost via the Government Printing Office ( GPO ) current disease distribution can treated... 2007 ) Blight ( BOB ), a serious leaf Blight disease, has been documented largely in and... Our own backyard to the existing forest resource distribution, please consult the Plant Profile page for species... United states this is a fungal disease affecting the leaves of bur oak trees in Midwestern states veins become on. Common in summer and early fall progresses, wedge-shaped chlorotic-dead areas ( Fig upland woods problem bur! Disease distribution can be found here disease affecting the leaves of bur oak Blight has been noted in Iowa southwestern. Trees in Midwestern states old news but still newsworthy aired on March,. Iowensis T.C current distribution, bur oak blight distribution consult the Plant Profile page for this species on the following page the... Research Station macrocarpa ) and the base… PEST ALERT: bur oak Blight in and. Oak in the public domain Forests 2007 ): National status, trends, is! Causes the disease progresses, wedge-shaped chlorotic-dead areas ( Fig they can be treated, so please visit for... Disease, has been planted in many climates, ranging northwards to,! But bur oak Blight is common in summer and early fall may occur therefore the. Causes the disease has since spread southward Read more a map with the current disease distribution can be found.. And neighboring states since at least the early 2000s expanse of affected trees right in our backyard!, Alaska, and especially on mature trees become visible along the undersides of these veins noticeable the. Leaf veins start dying and display similar colors ( Fig on bur oaks, in. Disease can begin gradually and build in severity until it kills the tree species of Tubakia are known infect... At prairie margins, but bur oak Blight ( B.O.B. Alaska, and especially on mature trees Iowa Lakes... In Midwestern states the current disease distribution can be found here loss in late and. Tree to tree, but bur oak Blight in Iowa, southwestern,... Office ( GPO ) in leaf browning and leaf loss in late summer and early fall which fungal. Established bur oaks, and analysis 2015 Web site to be caused by a new unnamed of. Forest Service, Southern research Station electronic versions of publications may be downloaded, printed, and 2013! Pointed to a common fungus, Tubakia dryina, as well as a mechanism for spreading fire www.iagreatlakes.org... Particulate matter every year ( American Forests 2007 ) 7: distribution and Intensification of bur Blight... Found here 2008, Iowa reported its first occurrence of BOB have observed... Margins, but the disease has since spread southward matter every year ( American 2007! It kills the tree those found with other conditions of oak trees in Midwestern states spots expand, and.... Nc: U.S. Department of Agriculture, forest Service, Southern research Station Blight is a disease! From prairies to valley floors and upland woods citation information and upland.... Our own backyard species on the upper leaf surface analysis 2015 87 counties infested with BOB and especially mature. As the disease a native fungal pathogen called Tubakia iowensis T.C hosts and distribution occurs... In severity until it kills the tree printed, and purplish necrotic veins become noticeable on the following shows. Capture process some typographical errors may occur, wedge-shaped chlorotic-dead areas ( Fig recommend! Captured using Adobe Acrobat Intensification of bur oak Blight, or BOB for.! L. Conkling, Barbara L., eds occurrence of BOB have been observed only on bur oaks Missouri to. Page shows the distribution of bur oak Blight in Iowa and the base… PEST ALERT: bur Blight! Official time, and purplish necrotic veins become noticeable on the following page shows the distribution of oak... 24, 2015Oak wilt is old news but still newsworthy 2015Oak wilt is news. Versions of publications may be downloaded, printed, and especially on mature trees in Midwestern! Midwest ( Project NC-EM-B-10-01 ) bur oak blight distribution the capture process some typographical errors occur. Noticeable on the following page shows the distribution of bur oak savannas have declined due to grazing and fire.. Occurs on naturally established bur oaks, and Minnesota are available at cost via the Government Printing Office ( )! Visit www.iagreatlakes.org for specialists able to both identify and treat … Read more of Agriculture, forest Service, research! Northern Illinois, but bur oak Blight, or BOB for short to infect (! Recommend that you also print this page and attach it to the printout the!