March 2015 practical winery & vineyard 49
35
30
25
20
15
10
5
0
35
30
25
20
15
10
5
0
Vineyard on Russian River BGSS Average
2009 2010 2011 2012 2013 2014
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2001
Graton Creekside BGSS Average 2001–2013
No trap data
2003–2005
BGSS
trapped
per
week
BGSS
trapped
per
week
These graphs are representative of west Sonoma
County blue-green sharpshooter (BGSS) counts.
Each bar is the average of all the block's traps for
one week. Monitoring at the Graton vineyard site
began in 1999. No Pierce's disease was observed
until 2005, and the uniform vine age along the
riparian area seemed to indicate PD had not been
an issue since planting several decades previously. Trapping was done from 1999 through 2001 at a number of riparian sites and discontinued because
no PD symptoms or dead vines were observed. During that time, blue-green sharpshooters were trapped in numbers that would usually translate to a
high incidence of PD. From 2005 through about 2007, PD-infected vines were found regularly in vineyards. After 2007, BGSS counts and PD incidence
declined to extremely low, virtually non-existent levels.
Monitoring at the Russian River vineyard site began in 2009, and counting dead vines due to PD was initiated after removal of dead vines that had
accumulated over several years. It is my observation that BGSS populations in west Sonoma County vineyards have increased since 2010, with PD
incidence lagging behind by a few years. BGSS may have hit a peak in some vineyards in 2012, 2013 and 2014. PD is known to be a cyclical disease as the
increased numbers of BGSS and diseased vines seem to be indicating for growers in west Sonoma County.
Laura Breyer, MS, Breyer's Vineyard IPM Service, Windsor, Calif.
2009 2010 2011 2012 2013 2014
BGSS March–May 16 15 113 209 159 142
PD vines removed na na 49 97 100 526
Data from one 30-acre vineyard on the Russian River.
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