[MPWG] Japanese stiltgrass disease update June 2 2010

[ForestRuss at aol.com]

MPWG:
 
The disease that was discovered to be killing Japanese stiltgrass,  
Microstegium vimineum, in Calhoun County, West Virginia during 2008 and  2009 has 
spread to new sites. The first signs of disease this year was in  scattered 
locations starting about May 7.  
 
In areas where the disease was active last fall there was limited  
germination of stiltgrass this spring and many plants that have  developed in those 
areas now show disease signs.  
 

Two years ago this road was completely dominated by stiltgrass that grew so 
 tall and thick that all the water bars on the road were obscured.  This  
area was hit by the disease last fall as the seed was starting to set.  The  
dominant greenery in this photo is black Cohosh and white aster.  Nearly  
all stiltgrass present at the site is diseased.  Within 100 feet of this  
photo there is healthy stiltgrass that is almost 18" tall. 
 
 
The following three photos were taken in an abandoned field area that had  
become a stiltgrass savannah.  The site has  scattered apple  trees and deer 
had helped to spread the stiltgrass across the hillside.   This savannah 
covers more than fifteen acres and showed no signs of disease in  2009.
 

The trail in the foreground has a heavy cover of sickly stiltgrass.   For 
several hundred feet of this trail nearly 100% of the stiltgrass plants are  
covered with lesions.



In some areas the thatch from last year is still easy to find because there 
 is very little new growth for 2010.

There are areas with no living stiltgrass plants and the natives are taking 
 off.
 

It appears that the fungus killing stiltgrass can survive a forest  fire.  
In early April a forest fire 
burned over 20 acres of Crummies Creek including areas where I had  
photographed the disease last year.  Some Japanese stiltgrass seed  survived the 
fire and germinated in early May but now nearly all plants are  showing 
disease signs.
 
At this time no one has determined the vectors for spread of the  disease 
but a paper on some of the specifics of the "Bipolaris"  disease has recently 
been published by Luke Flory of Indiana  University.
 
Sincerely,
 
Russ Richardson, Certified Forester
Crummies Creek Tree Farm
PO Box 207
Arnoldsburg, WV 25234
 
 
 
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