History Sit back and relax Make sure you’ve got a drink! Prepared for you by Eugene V. Bobukh.
You’ve prepared y our c ommunity for:
18
Minnesota First Detectors You’ve prepared your community for: Dutch Elm Disease
description
You’ve prepared y our c ommunity for:. Dutch Elm Disease. You’ve prepared y our c ommunity for:. Oak Wilt. You’ve prepared y our community for:. Emerald a sh borer. But… . What a bout BOB?. Prepare Your Community for B ur O ak B light: BOB. Bur Oak Blight: the details. - PowerPoint PPT Presentation
Transcript of You’ve prepared y our c ommunity for:
Minnesota First Detectors
You’ve prepared your community for:
Dutch Elm Disease
Minnesota First Detectors
You’ve prepared your community for:
Oak Wilt
Minnesota First Detectors
You’ve prepared your community for:
Emerald ash borer. But…
Minnesota First Detectors
What about BOB?
Prepare Your Community for
Bur Oak Blight: BOB
Minnesota First Detectors
Bur Oak Blight: the details
Fungal foliar disease (leaf spot) Tubakia species complex found in Europe and
Asia Bur oak-specific
Minnesota First Detectors
What Does it Look Like?
Note wedge-shaped blotches
Minnesota First Detectors
Is it in Minnesota?
Yes Confirmed in 3 counties
Hennepin Mille Lacs Sherburne
Minnesota First Detectors
BOB is found in a limited area
USDA, NRCS. 2011. The PLANTS Database (http://plants.usda.gov, 25 February 2011). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
Bur oak distribution is in green and the area with reported BOB occurrences is circled in red
Minnesota First Detectors
New find?
Symptoms noticed in upper Midwest since 1990s
Symptoms have increased in recent years
First symptoms recorded from southern MN
Minnesota DNR Forest Health Specialist found late-season disease attacking bur oaks
Minnesota First Detectors
What Trees are Affected?
Only bur oak - to date
Minnesota First Detectors
How Does it Spread?
Minnesota First Detectors
How Does it Spread?
Spores from infected leaf blades and petioles Spring infection
Minnesota First Detectors
5. Recognizable Symptoms?
Seen after mid-July Leaves turn brown along veins and in V-shaped
areas
Worse at bottom of crown and interior Slow-spreading but worsens each year Trees infected one year show symptoms the
following year
Minnesota First Detectors
BOB Symptoms
Leaves fall off after becoming completely brown During summer, black fruiting structures form
along leaf veins and petioles Can be easily seen with 10X magnifying lens Leaf symptoms usually more severe on lower
crown Trees infected with BOB susceptible to
secondary pests like two-lined chestnut borer and Armillaria root rot
Minnesota First Detectors
Hosts
Unique feature: some (but not all) infected leaves remain on tree during winter; healthy bur oaks shed all their leaves in the fall
Even a small number of leaves hanging on over the winter indicate BOB may be there
Leaf petioles remain intact Black fruiting bodies forming in late fall are
overwintering stage of the fungus Healthy trees are mixed with dying trees;
probably due to variation in resistance
BOB Symptoms
Minnesota First Detectors Other pests affecting bur oak
Fred Baker, bugwood.org
Joe O’Brien, bugwood.org
Steve Katovich, bugwood.org
Oak anthracnoseTwo-lined chestnut borer
Oak wilt
Minnesota First Detectors
Can Anything be Done?
Maintain health: water management, mulch Chemical injections: Propiconazole
Minnesota First Detectors
What to do if you see BOB
Contact the Minnesota Department of Agriculture “Arrest the Pest” hotline at 651-201-6684 (metro) or 1-888-545-6684 (toll free)
Contact info also found in the Forest Pest First Detector Manual
