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Vineyard IPM Scouting Report for week of 8 July 2013 UW-Extension Door County and Peninsular Agricultural Research
Station
NO. 10
Show and Tell – anthracnose and downy mildew Often I have written about a number of pests that often are or can be a problem in grape production. In many of these arti-cles, I have told about the biology and ecol-ogy of the pest and how to manage the pest. All of these articles are archived with a table of contents on the Door County UW-Extension website. Over time I have found that many growers appreciate this informa-tion and use it as a reference. However, for many of you, one of the main areas that you would like more information about is how to identify certain pest problems. This became readily apparent from the Wiscon-sin Grape Growers Educational Committee Survey that found pest identification was the most important topic of survey respon-dents. Often times when scouting, growers will recognize leaves, shoots, tendrils, berry clusters that appear to have a problem, but are not quite sure what the problem may be. Sometimes to help in diagnosis you will turn to the internet for help in trying to de-termine or identify a particular problem. You may search through hundreds of pic-tures, but none of them seem to resemble your problem. Over the past few years, I have been trying to assemble a collection of my own pictures that will help you in identifying pest problems. The problem is that it is very difficult to get pictures of pest or disease symptoms in vineyards because most of the vineyards are managed so well. When the opportunity arises to document actual vineyard pest problems in Wisconsin I am giddy with anticipation. I know these pest problems don’t make the growers happy, but the problems provide the opportunity for them as well as all of you to learn. continued on page 2.
Anthracnose on a shoot and leaves of Frontenac, 7.10.2013
Downy mildew on a berry cluster of wild grapes at PARS on 7.8.2013
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So this week is my opportunity to share with you some recent scouting pictures. Remember grade school and the opportunity to learn something new from your class-mates. Show and Tell is today. Take the opportunity to view the pictures and keep this report as a reference for two major disease problems – anthracnose and downy mil-dew. Also I would like to remind you that you can always send me digital pictures in which I will try to identify your problem. In addition, you can send pictures to the Plant Disease and Diagnostic Clinic at UW-Madison. The clinic fee schedule states that there is a $20.00 charge for examination and diagnosis of digital pictures. You may also send plant material for diagnosis of pest problems to the Disease and Diagnostic Clinic. Please see the website above for sample submission preparation and fees.
Anthracnose lesions on a shoot (A), leaf (B) of Fron-tenac and on a leaf (C), shoot (D), and berry cluster (E) of La Crosse.
A
B
C
D
E
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Anthracnose lesions on a leaf (A) and berry cluster (B) of Petite Pearl and anthracnose lesions on a leaf (C) and berry cluster (D) of Louise Swenson. Note: Petite Pearl has been reported to have good disease resistance to powdery mildew, downy mildew, and black rot, but apparently is moderately susceptible to anthrac-nose according to my current observations.
A
D C
B
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Downy mildew lesions on top of leaf (A and B), bottom of leaf (C), tendril (D), shoot (E), and on phylloxera galls (F). This is the worst infection of downy mildew that I have ob-served on wild grapes in a number of years.
B
C D
E F
A
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Brianna at PARS 7.9.2013
Foch at PARS 7.9.2013
Frontenac at PARS 7.9.2013
Development of wine grapes in the grape variety trials at the Peninsular Agricul-tural Research Station (PARS) Sturgeon Bay, WI and West Madison Agricultural Research Station (WMARS), Madison, WI
Brianna at WMARS 7.10.2013
Foch at WMARS 7.10.2013
Frontenac at WMARS 7.10.2013
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13
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Development of wine grapes in the grape variety trials at the Peninsular Agricul-tural Research Station (PARS) Sturgeon Bay, WI and West Madison Agricultural Research Station (WMARS), Madison, WI
La Crosse at WMARS 7.10.2013
Marquette at WMARS 7.10.2013
La Crescent at PARS 7.9.2013
La Crosse at PARS 7.9.2013
Marquette at PARS 7.9.2013
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La Crescent at WMARS 7.10.2013
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Petite Pearl at PARS 7.9.2013 Petite Pearl at WMARS 7.10.2013
NY76 at PARS 7.9.2013 Frontenac gris at PARS 7.9.2013
Leon Millot at PARS 7.9.2013 Vignoles at PARS 7.9.2013
Grape progress update of other varieties in the grape variety trial located at the Peninsular Agricultural Research Station.
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Noiret at PARS 7.9.2013 MN 1200 at PARS 7.9.2013
MN 1258 at PARS 7.9.2013
Pristine phytotoxicity
MN 1200 at PARS 7.9.2013
Grape progress update of other varieties in the grape variety trial located at the Peninsular Agricultural Research Station.
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Degree Day1 (base 50) Accumulation from April 1 to July 7, 2013 at Pen-
insular Agricultural Research Station in Sturgeon Bay, WI
Date 2013 2012 5 Year Average2
4/1 to 7/7 754 997 861
1Modified method. 2Average from 2008 to 2012.
Degree Day1 (base 50) Accumulation from April 1 to July 7, 2013 at West
Madison
Date 2013 2012 5 Year Average2
4/1 to 7/7 1098 1369 1233
1Modified method. 2Average from 2008 to 2012.
Accumulated degree days1 (base 50) for the month of March in Sturgeon Bay and
Madison, WI.
1Modified method. 2Data from http://www.doa.state.wi.us/degreedays/
Year Madison WI Sturgeon Bay WI
GDD (base 50, ceiling 86)
2013 12 0
2012 252 106
2011 13 3
2010 72 38
2009 51 12
2008 1 0
2007 90 41
2006 22 7
2005 40 9
2004 49 11
Please scout your vineyards on a regularly scheduled basis in an effort to manage problem pests. This report
contains information on scouting reports from specific locations and may not reflect pest problems in your
vineyard. If you would like more information on IPM in grapes, please contact Dean Volenberg at (920)746-
2260 or [email protected]