Disease Digest

Disease, Demystified

What are control strategies for managing oak wilt disease? What do we know about beech leaf disease? Does rose rosette virus affect ‘Knockout’ roses? Which crabapples have good genetic resistance to apple scab disease and how does this compare to 20 years ago? Does apple scab on the fruit matter (as seen on the lead slide for this bygl-alert)?

 

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Jim Chatfield
Erik Draper

Don't Pick That Scab!

As a committed crabarian, I cringe along with everyone when driving into a town or walking along a street and seeing the barren, defoliated canopies of certain crabapples this summer and now into the fall. Out darn scab! (double apologies to W.S.).

 

Apple scabSymptoms of apple scab on...
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Jim Chatfield
Bent Science Salon: Weird Things in the Woods chatfield.1 Thu, 09/07/2017 - 14:16

  Come one, come all. The Bent Science Salon officially opens in two weeks, on Thursday, September 21 at 7:00pm. First up: Weird Things in the Woods, channeled through a Weird Thing himself, yours truly, Jim Chatfield. This is only the first of these salons, continuing on the third Thursday of every month: next will be Dan Herms on Plant Phenology (Not Phrenology) and Climate Change, on October 19.

 

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Jim Chatfield

More Beech Diagnostics

American beech (Fagus grandifolia) is one of our most elegant woodland and parkland trees; it puts the sylvan in silviculture. There are many problems afoot, however, both large and small.

 

  For this alert, though, let us set aside the death and life realities of killer beech bark disease and the Boggsian itty-bitty bite/peench story of the beech blight (boogie-woogie) aphids (http://bygl.osu.edu/node/883). Let us look at...

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Jim Chatfield

Peony Measles

Cultivate your own garden, said Voltaire at the end of Candide.  Looking homeward, I note that peony measles, first seen in mid-July has continued to develop.  Measles, or red spot or leaf blotch or Cladosporium leaf blotch disease are alternative names for this fungal disease. It is caused by, you guessed it, Cladosporium paeoniae or, who knew, with its new moniker, Dicholocladosporium chlorocephalum. 

 

  On the upper leaf surface, reddish and brownish “measles”-like spots develop earlier in summer, now coalescing into purple blotches...

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Jim Chatfield

Crepe Myrtles For Ohio

While in Maryland and Virginia recently our Extension Nursery Landscape and Turf Team of diagnosticians admired crepe myrtles (Lagerstroemia indica) in whites, reds, and lavenders.  Absolutely gorgeous trees for their flower displays and their attractive bark.
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Jim Chatfield

The Other Guignardia...

Joe Boggs wrote a great article “Guignardia Leaf Blotch Running Rampant” the other day, which caused me to reflect on another Guignardia fungus often ignored, but very important.  The other Guignardia, Guignardia bidwellii, is one responsible for causing the disease Black Rot of Grape.
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Erik Draper
Curtis E. Young
Guignardia Leaf Blotch Running Rampant boggs.47 Tue, 07/25/2017 - 10:38
Our continual wet weather over much of Ohio this season has been a two-edged sword. On one hand, we haven't had to drag hoses to water our landscapes. On the other hand, a number of fungal plant pathogens that require wet conditions to infect and produce their associated diseases are running rampant. Such is obviously the case for Guignardia aesculi; the fungus responsible for Guignardia Leaf Blotch of Aesculus.
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Joe Boggs
Gallignostics chatfield.1 Mon, 07/17/2017 - 10:21

  Let us call this A Case of Gallignostics. Plant galls are defined as abnormal plant growths caused by a gall-maker; the gall-maker being certain insects, mites, fungi, and bacteria. From horned oak gall to bacterial crown gall, from maple bladder galls to cedar-apple rust galls, there are many galls of interest to horticulturists. Relative to all this, Joe Boggs recently got an e-mail from Michael Goldman of the Grange Insurance Audubon Center:

 

  I'm a big fan of the BYGL, and found something here that might be interesting for it.  The pictures I took look like some...

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Jim Chatfield
Joe Boggs