Editor: Imed Dami, PhD
Assistant Professor and Extension Viticulture Specialist
Department of Horticulture and Crop Science
Ohio Agricultural Research and Development Center
1680 Madison Avenue
Wooster, OH 44691-4096
Phone: (330)-263-3882
Fax: (330)-263-3887
E-mail: dami.1@osu.edu
www.oardc.ohio-state.edu/grapeweb/

 

 
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Content:
AARS FIELD DAY
MID-SUMMER INSECT CONCERNS
SCOUTING AND GENERAL VINEYARD MAINTENANCE
VARMINTS AND VERAISON
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AARS Field Day
By David Marrison
Attend the Ohio Grape and Wine Field Day at the Ashtabula Agricultural
Research Station Thursday, August 16, 2007 from 2:00 to 4:30 pm. Some of
the topics that will be discussed at this event include: Cabernet Franc
training systems and clonal evaluation studies, insect and disease
management update, Traminette rootstock evaluation, South Centers
Viticulture update and a wine tasting of experimental cultivars will follow.
Several of the resource people involved in the Ohio Grape and Wine Field
Day will also be participating in the Twilight Tour. see attachment for
complete details

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Mid-Summer Insect Concerns
Roger Williams and Dan Fickle

Many areas of the state are experiencing high populations of Japanese beetles this season despite wide spread drought conditions.  Grapes are usually more drought tolerant than other agricultural crops but when combined with defoliation from foliar feeding adult Japanese beetles it’s a recipe for sever vine stress, even for cultivars we normally consider tolerable to Japanese beetle like Concord and Niagara. Young vines are extremely susceptible to defoliation as shown in this picture.  There are several pesticides labeled for control of this pest but remember even though we have probably reached peak numbers in most areas of the state the adults will still be active for several weeks so more than one application of pesticide may be necessary to prevent sever defoliation. 
It is once again time to be concerned about controlling late season grape berry moth.  This is the generation that inflicts the most damage to ripening fruit and facilitates bunch rots late in the season.  Larval damage is usually visible as reddish “stung” areas on the green berries often accompanied by webbing together of the fruit.  Scouting perimeter areas for berry moth damage should be conducted every couple of weeks until mid September.  If bunch damage exceeds 3/100 (3%) control measures should be considered.  Remember we now have a pyrethroid labeled for grapes (Baythroid, Bayer) which has a 3 day harvest interval and therefore may be used for late season insect problems. Consult your small fruit spray guide for recommendations.  *See attachment for complete document with pictures.

http://www.hort.purdue.edu/hort/ext/extpubs.shtml

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Scouting and General Vineyard Maintenance

By David Scurlock
 
Scouting the vineyard for insects and disease problems is one of those thankless jobs that can pay off with early detection of problems that may go unnoticed.  Routine walking through the vineyard in especially known problematic areas in the past can alert you early so that you can action. Try to adopt a time each week to survey as much of the vineyard that you have time for to look for trouble.  If you don’t find it first it will find you and the results will not be the same.
INSECTS: This year the Japanese Beetles are eating their way through the hearts of many vineyards across the state.  Luckily they can be easily kept in check with Sevin or Danitol.  There are other pesticides that are effective against the beetle. Refer to your spray guide and find one that does the job and is economical. The Japanese Beetle will have several flushes throughout the season so it is not just a one time cure.  You generally will get flushes of beetles after rains that soften the ground allowing the adults to emerge.
DISEASE: The dry weather has been beneficial in respect to the absence of disease.  The production of Phomopsis occurred early in the season.  I have not noticed any problems with other disease symptoms at this time. 
CANOPY: Open up the canopy through the removal of laterals to allow light to mature and color the fruit and rid the vine of off bloom(off bloom is fruit that sets on laterals and lowers fruit quality if picked at harvest).  Remove suckers at the base of vines to promote top growth unless you need trunk replacement parts. 
WEEDS: Weeds thrive no matter what.  If you have a young vineyard the best thing that you can do for them is keep a weed free environment.  The weeds compete for nutrients as well as water.  Your application of a pre-emergent herbicide such as Surflan after planting may be losing its effectiveness at this stage and you may have to do some spot spraying or hand hoeing to keep the weeds in check.  Older vines are going to be more tolerant to some weed competition.
FERTILIZATION: Check the overall growth and color of your vines.  The addition of foliar sprays to correct symptoms may be necessary as a quick fix.  Foliar sprays of  potassium nitrate can be used to correct potassium problems, but long term benefits are better with soil applications of potassium. Nitrogen uptake can also be in limited supply to the clusters due to drought conditions. A couple foliar applications of Urea around veraison at 10 pounds per 100 gallons will boost assimilable nitrogen without any negative side effects.  Soil tests should be part of your regular maintenance program every third year and petiole tests should be performed every year.  The time to collect petioles is now through August 15.   Petioles should be taken from a couple of leaves that are approximately 7 to 10 leaves from the tip of a shoot.  These are defined as the most recently fully expanded leaves.  Try not to get damaged leaves.  These leaves should be fully exposed to the sun, not from under the canopy.  Depending on variety approximately 50 petioles should be collected per sample from 25-30 vines representative of the area you are trying to analyze.  There is no magic number of vines.  There can be 600 to1000 vines per acre or more depending on spacing, so you must decide how to divide up your vineyard for the best representative sample.  Testing can save you money in the long run by supplying just what the vine says it needs.

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Varmints and Veraison

By David Scurlock
 
Veraison is coming up very soon and it is not too early to start thinking about critter control.  I would like to use the definition of a weed as an analogy of a varmint.  A weed is any plant that is growing where it is not wanted.  A varmint is any animal that is eating where it is not wanted.  Varmints can take on the innocent persona of a Robin.  In large enough numbers they can rapidly come in conflict with the grape producer.  A plan to curb the diet through the use of scare tactics such as propane cannons, bird squawk boxes, raptor perches, scare eyes, sucrose applications and netting are a few things in our arsenal to deter feeding habits.  Once the birds have started feeding even the physical barrier of the netting is sometimes not enough to keep the birds from causing damage.  The physical damage to the berries then allows secondary critters to come in such as insects and disease. Clusters that have been protected with sprays throughout the season are now vulnerable to bunch rot and can cause the grower to harvest a crop early to save from losing it all together.  Other varmints that come into play at this time are raccoons, possums, turkeys and deer.  They all have appetites and the candy store aromas from the vineyards are calling their numbers.  Particularly in a dry season the grape vineyard is an open invitation to many animals. Box traps are devices that can be placed on game trails or areas that you anticipate animal activity.  These traps must be checked on a regular basis so that the captured animal can be relocated without suffering.  There are a number of repellents that can be found by surfing the web.  Some of these chemicals taste bad(hot sauce) and others repel(blood by-products and coyote urine).  Changing up your deterrents so that animals do not become accustomed to them is your best strategy.  Dogs have been used inside orchards that are surrounded by the Invisible Fence System.  Here again the dogs need to be looked after and even they need to sleep sometime.  Deer fence, either electric or just an eight to ten foot barrier, is another consideration. Cost, time and animal pressure will dictate what combination of methods is best for your situation.