Bur oak blight, caused by a new species of Tubakia

Blighted bur oak trees Pycnothyria

A recently published review of the disease is found at: Harrington, T. C., and D. McNew. 2016. Bur oak blight. Pp. 16-19 In: Diseases of the Great Plains. A. D. Bergdahl and A. Hill, eds. U.S. Forest Service, Gen. Tech. Rep. RMRS-GTR-335.  Fort Collins, Colorado. (pdf of book chapter)

The formal description of bur oak blight and Tubakia iowensis was recently published in Mycologia and is available as a pdf. (Harrington, T.C., D. McNew and Hye Young Yun. 2012. Bur oak blight, a new disease on Quercus macrocarpa caused by Tubakia iowensis sp. nov. Mycologia 104: 79-92).

We recently described three new species of Tubakia on oaks: T. macnabbii, T. tiffanyae and T. hallii after Sande McNabb, Lois Tiffanyi and Richard Hall, our late colleagues at Iowa State University. These new species are generally not as serious as bur oak blight, but they can cause significant defoliation on some trees. Harrington, T. C., and D. M. McNew. 2017. A reevaluation of Tubakia, with three new species and six new combinations. Antonie van Leeuwenhoek   https://doi.org/10.1007/s10482-017-1001-9

Harrington, T. C., and D. L. McNew. 2016. Distribution and intensification of bur oak blight in Iowa and the Midwest. Pp. 105-110 In: K. M. Potter and B. L. Conkling, eds. Forest Health Monitoring: National status, trends, and analysis 2015. US Forest Service Gen. Tech. Rep. SRS-213. (pdf of book chapter).

A brief update and comparison of BOB with the invasive laurel wilt can be found here: Harrington, T. C. 2013. Exotic pathogens or shifts in climate? Luarel wilt and bur oak blight. pp. 39-41 In: Proceedings, 24th USDA Interagency Research Forum on Invasive Species. Pubication FHTET 13-01. Forest Health Technology Enterprise Team: Fort Collins, CO. 124 p. (pdf of manuscript).

A poster of the disease cycle is available.

This is a link to a 2010 video (actually a powerpoint presentation) on bur oak blight, caused by an undescribed Tubakia - "What about BOB?"

An article (Feb. 2011) on bur oak blight was published in the ISU Extension 2011 Horticulture & Home Pest Newsletter, and a recent update (Sep. 2012) includes some discussion of potential fungicide control for high-value trees 2012 Horticulture & Home Pest Newsletter.

There's also a short video clip from a 2008 TV news report on the disease.

The US Forest Service has issued a 2-page pest alert on bur oak blight.

The current (as of Fall 2015) ISU distribution map of confirmed Tubakia iowensis is shown below as magenta counties superimposed on the gray distribution of Quercus macrocarpa. We think this BOB distribution roughly coincides with the distribution of Q. macrocarpa var. oliviformis. Thanks to the numerous cooperators in Iowa and neighboring states for sending samples!

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