Bur Oak Blight in

Minnesota

Tree Care Advisor Core Course Training 2012

You’ve Prepared Your Community

for…

Dutch Elm Disease

You’ve Prepared Your Community

for…

Oak Wilt

You’ve Prepared Your Community For

Emerald Ash Borer

But…What About BOB?

Prepare Your Community for

Bur Oak Blight = BOB

Bur Oak Blight…the details

Fungal Foliar Disease (Leaf Spot)

Tubakia species

Bur Oak Specific

1. What Does it Look Like?

Note “wedge-shaped”

symptomology

2. Is It In Minnesota?

Yes

Confirmed in Hennepin, Mille Lacs and

Sherburne Counties

3. What Trees Are Affected?

Only Bur Oak…to date

4. How Does It Spread?

4. How Does It Spread?

Spores from infected leaf blades and petioles

Spring infection

5. Recognizable Symptoms?

Summer (July >) leaf spotting and blotching

Leaves turn brown/gray

Worse at bottom of crown and interior

Many leaves retained through winter

Worsens each year

6. Can Anything Be Done?

Baby Steps

Maintain Health: Water Management, Mulch

Chemical Injections: Propiconazole

7. For More Help and Information…

For BOB testing:

•Collect branch tips with symptomatic and healthy

leaves from several locations on the tree;

•Wrap them in dry paper toweling (no plastic bags,

please), and send them to:

Plant Disease Clinic

Department of Plant Pathology

495 Borlaug Hall

1991 Buford Circle

St. Paul, MN 55108