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Vineyard IPM Scouting Report for week of 21 June 2010

UW-Extension Door County and Peninsular Agricultural Research Station

Sturgeon Bay, WI

Scouting in the Vineyard I am sure many of you are familiar

with the cliché “An ounce of prevention is worth a pound of cure”. This cliché has a couple of meanings when applying inte-grated pest management in the vineyard. First, scouting results in early detection of pests and may reduce the risk of pest outbreaks. Be aware that economic thresholds have not been established for most grape pests. Realize, however, that for some pests, for example, downy mil-dew, powdery mildew, black rot, and mul-ticolored lady beetles at harvest that eco-nomic thresholds are extremely low. Sec-ond, when pesticides are needed to pro-tect the crop, these protective pesticides or “ounce of protection” may save you money down the road by not having to fight a pest outbreak. Prevention starts with scouting and there are some basic concepts that you should understand when scouting in the vineyard.

How often and when should a vine-yard be scouted? The vineyard should be scouted regularly with a minimum of once per week. I like to scout the same vine-yard on the same day of each week during the growing season to see how pests and the crop are progressing. This regular schedule will let you track vine/grape development (phenology) -see page 2 throughout the growing season. How many vines should you sample? You should scout a minimum of 100 vines per vineyard. These vines should be lo-cated on the perimeter of the vineyard and the interior of the vineyard. You should randomly scout the vines or sample different vines/clusters each week. As the growing season progresses, you will want to scout leaves within the can-opy for potential pests and also inspect grape clusters. If a pest(s) are found at a certain sampling site, the pest and location needs to be recorded. Keeping concise clear records on pest(s) location, grape variety, and date helps you es-tablish a history that may be beneficial in future growing seasons. To re-identify leaves or grape clusters that have had pest problems, the leaves or grape clus-ters can be marked with plastic marker tape or survey tape. This allows you to track the progress of the pest(s) or evaluate the pesticide efficacy if a pesticide has been applied.

Keep good scouting records by us-ing a scouting form as above devel-oped by Rufus Isaacs at Michigan State University. For copies of this form, see the following link at, www.isaacslab.ent.msu.edu/grapescout/scout.pdf

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Before you begin scouting, you should construct an accurate vineyard map. The map should identify grape varieties, wooded perimeter areas, and the location of wild grapes that are nearby. Sites that are adjacent to the vineyard such as wild grapes on fence lines or border areas should be monitored along with the vineyard for risk assessment.

As you progress in your vineyard and keep accurate records, you will soon identify areas that have high pest potential, often referred to as “hot spots”. These hot spots may be near wooded perimeters, wild grapes, or areas where air flow is impeded. Once these “hot-spots” are identified they should be scouted first for disease and insect pests.

To save on that pound of cure for grape pests, establish monitoring sites in the vineyard, scout on a regular schedule, keep accurate records of pests, and identify “hot-spots” for pests in the vineyard.

Dormant Early bud swell

Late bud swell

Bud burst

1- to 3-inch shoots

4- to 8-inch shoots

10- to 16-inch shoots

Immediate prebloom

First Bloom

Full bloom

Buckshot berries

Bunch closure

Veraison

Ripe for harvest

The fourteen major developmental stages (phenology) of grapes. When scouting the vineyard, be sure to record the stage of development of the grapevine or berries on the IPM scouting form.

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What’s lurking

in or near the vineyard this week?

Grape Tumid Galls were found on wild grapes this week at the Peninsular Agri-cultural Research Station. The galls can often be found on leaves, petioles, and flower clusters. Within the galls is a developing larva that upon maturity will exit the gall and drop to the ground and pupate within the soil. The galls seldom ever cause economic loss in the vineyard. When scouting , evaluate grape leaves close to the ground as these leaves are often the preferred egg laying sites of the Grape Tu-mid Gallmaker. Note: the Grape Tumid Gallmaker is of-ten referred to as the Grape Tomato Gall in the older lit-erature.

Top of leaf

Bottom of leaf

Gall on leaf and leaf petiole

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Brianna at PARS 6.21.2010 Brianna at WMARS 6.21.2010

Foch at PARS 6.21.2010 Foch at WMARS 6.21.2010

La Crescent Flowering at PARS 6.21.2010 La Crescent at WMARS 6.21.2010

Development of wine grapes at the Peninsular Agricultural Research Station (PARS) Sturgeon Bay, WI and the West Madison Agricultural Research Station (WMARS), Madison, WI. Buds damaged by frost at PARS on 5/8 and 5/9/2010

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1New buds selected at PARS this week for following phenology since buds featured in previous

issue (week of 5.10.2010) of the IPM report were damaged by frost.

6.22.2009

6.22.2009

6.22.2009

6.22.2009

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Development of wine grapes at the Peninsular Agricultural Research Station (PARS) Sturgeon Bay, WI and the West Madison Agricultural Research Station (WMARS), Madison, WI. Buds damaged by frost at PARS on 5/8 and 5/9/2010

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La Crosse at PARS 6.21.2010

Marquette at PARS 6.21.2010

La Crosse at WMARS 6.21.2010

Marquette at WMARS 6.21.2010

Wild grape at PARS 6.21.2010 Pea sized berries

1New buds selected at PARS this week for following phenology since buds featured in previous

issue (week of 5.10.2010) of the IPM report were damaged by frost.

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Date 2010 2009 5 Year Average2

6/20/2010 648 482 592

Degree Day1 (base 50) Accumulation since April 1, 2010 at Peninsular

Agricultural Research Station in Sturgeon Bay, WI

Date 2010 2009 4 Year Average2

6/20/2010 907 699 788

Degree Day1 (base 50) Accumulation since April 1, 2010 at West Madison

Agricultural Research Station, Madison, WI

1Modified method. 2Average from 2006 to 2009.

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 dean.volenberg@ces.uwex.edu

1Modified method. 2Average from 2005 to 2009.

Year Degree days (base 50)

2010 42

2009 12

2008 0

2007 37

2006 9

2005 8

2004 9

Accumulated degree days1 (base

50) for the month of March at Pen-

insular Agricultural Research Sta-

tion.

1Modified method.

Date Low °F

5/3/2010 44

5/4/2010 48

5/5/2010 41

5/6/2010 37

5/7/2010 32

5/8/2010 291

5/9/2010 291

Low temperatures reported

at Peninsular Agricultural

Research Station, Sturgeon

Bay, WI.

1Frost damage reported to

some grape varieties in grape

variety trial.