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eViticulture

2006 Best Management Practices Report

Demonstration and Verification of Best Management Practices for Winegrape Production in the Ozark Mountain Region

Viticulture Consortium, East 2006 Progress Report

Prepared by: Andy Allen, Donn T. Johnson and R. Keith Striegler

Objectives

  1. To conduct surveys to establish a benchmark and quantify progress in adopting grape best management practices and to identify constraints to implementation in Arkansas and Missouri.
  2. To demonstrate grape best management practices.
  3. To disseminate information about grape management, pests and diseases in a timely manner.
  4. To produce a Wine Grape Integrated Production Systems Workbook for use in grower grape best management practices workshops.

Summary of Major Accomplishments and Results

Objective 1: To conduct surveys to establish a benchmark and quantify progress in adopting grape best management practices and to identify constraints to implementation in Arkansas and Missouri.

  • Results from the survey conducted in fall 2005 regarding current grapevine canopy, insect and disease management practices have been compiled and summarized. The summary is included as a separate appendix to this report. A manuscript is being prepared for submission to HortTechnology. Results will also be published in the ICCVE newsletter.

Objective 2: To demonstrate grape best management practices.

  • Demonstration blocks were maintained by Keith Striegler and Andy Allen at each of the six cooperating vineyard sites in Arkansas and Missouri. These locations were Altus and Hindsville, Ark.; Ste. Genevieve, St. James, Hermann/Augusta and Columbia, Mo.

    Vines were balance pruned during the winter of 2005-2006. Selected canopy and crop load management practices were to be performed in each of these blocks, depending on the variety and trellis system.

    At Altus, Ark., the vineyard block was Merlot trained to a Vertical Shoot Positioned (VSP) trellis, and the management practices used were shoot thinning, leaf removal within the fruiting zone, cluster thinning and all treatment combinations.

    At Hindsville, Ark., the vineyard block was Chambourcin trained to a high-wire, single-curtain trellis, and the management practices were shoot thinning, shoot positioning, leaf removal, cluster thinning and all treatment combinations.

    At Ste. Genevieve, Mo., a block of Chardonel trained to VSP was used, and the practices used were the same as those at Altus.

    At St. James, Mo., the block was Chardonel trained to a high-wire, single-curtain trellis system, and the management practices included shoot thinning, shoot positioning, cluster thinning and all treatment combinations.

    At Rocheport, Mo., the block was Vignoles trained to a high-wire single-curtain trellis system, and the practices included shoot thinning, shoot positioning, leaf removal and all treatment combinations.

    At Hermann, Mo., a block of Vignoles trained to a high-wire, single-curtain trellis was used. The treatments in this case were designed to reduce cluster susceptibility to bunch rot by altering the very tight cluster architecture of Vignoles, which is highly susceptible to bunch rot. These treatments included leaf removal, brushing of the clusters and spraying with Stylet oil, all at trace bloom.

    These demonstration blocks, with the exception of Ste. Genevieve and Altus, were harvested the day before the growers harvested the entire variety block. Yield, cluster counts, and, where appropriate, bunch rot incidence data were collected. Also, berry samples for average berry size and fruit composition analysis were collected. Other variables were calculated from these data.

    In the Altus, Ark., Merlot block, the vines displayed uneven budburst and shoot growth possibly as a result of winter injury. Consequently, we were unable to use this block.

    In the Hindsville, Ark., Chambourcin block, few statistically significant treatment differences were observed in 2006 (data not shown). Hot, dry conditions and an inadequate supply of irrigation water combined to give a growing season with several periods of severe water deficit.

    The Chardonel demonstration block at Ste. Genevieve, which could not be used in 2005 due to poor vine growth, was moved to a more vigorous area of the vineyard in 2006. Unfortunately, very low crop level throughout the Chardonel blocks at this vineyard precluded data collection during the 2006 season. This was most likely the result of very severe drought stress during the 2005 growing season combined with high crop loads on a majority of the vines.

    In the St. James, Mo., Chardonel block, the treatments had no significant effect on any of the variables measured except cluster number per vine . Treatments that featured the combination cluster thinning and shoot thinning significantly reduced cluster number per vine.

    At the Rocheport, Mo., Vignoles block, the number of berries per cluster and cluster weight were significantly increased by shoot thinning, while shoot thinning was associated with significantly lower titratable acidity. Leaf removal was similarly but less consistently associated with the effects. Although not significantly different, shoot thinning, and to a lesser extent leaf removal, was also associated by higher Brix and pH levels compared to control and shoot positioned-only vines. Canopy management practices had inconsistent and insignificant effects on all other variables measured.

    In the Vignoles cluster architecture modification study at Hermann, Mo., two studies were conducted. The control, leaf removal and brushing treatment vines from 2005 were untreated in 2006. Yield and cluster numbers were collected at harvest to determine if there were any carryover effects of the treatments from 2005 on yield.

    Prior studies in other areas had indicated that leaf removal at trace bloom severely reduced bud fruitfulness in the subsequent season. We hypothesized that with the longer and warmer post-harvest growing season in Missouri that the vines would overcome the negative effects of leaf removal at trace bloom.

    Neither leaf removal nor brushing in 2005 had any carryover effects on yield or fruit composition in 2006. In the second investigation, the cluster modification treatments were applied to vines in another location within the same vineyard. Spraying with a 2 percent solution of Stylet Oil at trace bloom was added to the control, leaf removal and brushing at trace bloom treatments.

    Only leaf removal at trace bloom had a significant effect on any variable. Leaf removal reduced the percent rot clusters when compared to the Stylet oil treatment and reduced cluster weight, berry weight, berries per cluster, and the number of berries in the interior of the cluster compared to the untreated control vines.

    There was no significant effect of any treatment on fruit composition, although fruit from leaf removal treatment vines was slightly more mature than other treatments.

    Vineyard pruning workshops were conducted at each location in January 2006. Half-day field workshops ("Tailgate meetings") were held in March/April, May, June and July at the six demonstration vineyard sites. The sites with their average attendance for 2006 (in parentheses) were:

    • Arkansas: Altus (14 growers) and Hindsville (6)
    • Missouri: Ste. Genevieve (15 growers), St. James (10), Hermann (17) and Rocheport (15).

    During these workshops, Keith Striegler, Andy Allen, Donn Johnson and Barbara Lewis talked to between 65 and 90 growers and extension personnel each month. In addition, George Leavitt, Ph.D., was brought in as a special guest speaker during the June tailgate meetings to discuss grapevine trunk diseases and powdery mildew. The best winegrape management practices topics covered included:

    • Demonstration of canopy and crop load management practices including shoot thinning, shoot positioning, leaf thinning and cluster thinning.
    • Petiole and soil sampling for vineyard nutrient management.
    • Irrigation.
    • Weed management.
    • Pesticide use and pre-harvest intervals.
    • Demonstration of grape pest scouting and decision-making pest management program for grape berry moth, grape aerial phylloxera, grape root borer, grape scale, Japanese beetle and green June beetle.

    Growers in these six demonstration vineyards in Missouri and Arkansas were shown when and where to set out pheromone traps for grape berry moth (at edge of woods by vineyard by April 1 and move to vineyard center in mid-May). These growers or a scout, already under their employ, kept weekly insect trap count records for Missouri vineyards and Arkansas vineyards.

    Trap data were conveyed weekly to Donn Johnson by phone or e-mail and uploaded into a table of trap catch on two Internet pages:

    At field workshops in June and July, growers were shown how to make cluster damage estimates by inspecting 300 clusters for worm damage during each generation of grape berry moth. The recommended economic threshold was to apply insecticide only to the vineyard edge vines for first generation in May and early June and the whole vineyard for later generations only if more than one percent of clusters had new worm damage.

    In 2006, Donn Johnson and Barbara Lewis installed a Spectrum™ WatchDog weather station (Spectrum Technologies, Inc., 12360 South Industrial Dr., East Plainfield, IL 60585; 800-248-8873) at each of the six demonstration vineyard locations during the March/April tailgate meetings. This weather station has software to model occurrences of black rot, botrytis, downy and powdery mildew infection events.

    The grower, vineyard manager or another designated employee at each of the sites was instructed in how to download the data from the weather station and plug it into the disease models to determine if there had been any infection events in their vineyards. They also e-mailed the weather station data to Donn Johnson.

    Johnson used weather data from local official reporting weather stations near the demonstration vineyards to run the models and posted the results for each area on his Web site. In 2007, the software's predictive capabilities will be used to predict infection events for each of the diseases, and this information will be communicated to growers via Web site, electronic advisory and phone in order that they may take action if necessary when a disease event is forecasted in their area.

Objective 3: To disseminate information about grape management and pest and disease events in a timely manner.

  • Information on key insect pests and diseases was collected during the 2006 season. This information, as well as recommendations for canopy management and other viticultural practices, was provided to growers electronically (Web site) and face-to-face at vineyard workshops. A summary of insect pest and disease information follows:

    • Grape Berry Moth (GBM)

      The mean season total catch of GBM in pheromone traps in vineyards varied considerably relative to risk (increased with percentage of vineyard adjacent to woods) as follows:

      • Missouri at Ste. Genevieve (25.5 moths = low risk)
      • Hermann (112.5 = high risk)
      • Rocheport (23 = low to moderate risk)
      • St. James (180 = high risk by shed and 176.5 = moderate to high risk by tower)
      • Arkansas at Hindsville (75.7 = high risk and only 14.3 = low risk and all caught before placement of mating disruption ties on June 1).

      All vineyards reported less than 1 percent cluster damage due to feeding by GBM larvae. No GBM damage was observed in the three mating disruption blocks in Hindsville, Ark. Daily maximum and minimum temperature and rainfall data for select grape growing counties in Missouri and daily maximum and minimum temperatures for grape growing zones in Arkansas were used to generate graphs of cumulative degree-days for GBM (developmental base 47.14В°F and upper threshold of 93В°F).

      Each graph noted predicted periods of grape berry moth hatch (spray periods) for each generation in each grape-growing county in Arkansas and Missouri This information was available on the Arkansas/Missouri Fruit IPM Web site. This site also had specific vineyard trap catch data and management recommendations.

    • Japanese Beetle (JB)

      In 2005 in Northwest Arkansas, adult JB flight occurred from June 1 to mid-August in Springdale, Ark. Season total counts of adults per JB Jumbo trap in Arkansas were:

      • 91,394 in rural Elkins
      • 86,364 in the Springdale vineyard
      • 62,663 in urban Fayetteville
      • 45,852 in University of Arkansas-Fayetteville Farm
      • 33,100 in the Hindsville vineyard
      • 55 in rural Berryville

      Whereas in Missouri, counts were:

      • 3,868 in Ste. Genevieve
      • 12 in Purdy
      • 0 in St. James, Hermann and Rocheport

      In 2006, adult JB flight occurred from June 1 and ended in mid-August in Fayetteville, Ark. Season total counts of adults per JB Jumbo trap were:

      • 131,879 in rural Elkins (a third more than 2005)
      • 67,284 in urban Fayetteville
      • 31,823 in the Hindsville vineyard

      In addition, we glued 14 JB yellow funnels with floral/pheromone dual baits to tops of 3-gallon plastic storage boxes. Traps were placed 200 feet apart on the north perimeter of the University of Arkansas-Fayetteville Organic Fruit Farm. These traps mass trapped a total of 484,274 JB. This trapping significantly reduced foliar damage to the organically managed small fruits, grapes and apple trees compared to a block of conventionally sprayed apples a quarter mile to the east.

    • Green June Beetle (GJB)

      The flight of GJB in the Ozarks was observed from late-June to late-August. The overall GJB population in 2006 was higher and more widespread than in 2005 as evidenced by the fact that most fruit growers from Altus, Ark., to Purdy, Mo., applied insecticide spray to minimize GJB damage to ripe fruit.

      In 2006, we obtained funding to collect and identify semiochemicals produced by GJB adults. To detect a broader range of volatiles, we used a SPME fiber (50/30 carboxen/DVB/PDMS fiber from Supelco, Bellefonte, Pa.) to collect headspace volatiles for 30 minutes from GJB adults feeding on ripe nectarine, apple and peach.

      We inserted SPME fiber sample for 30 seconds in either a Shimadzu GC/MS (University of Arkansas Mass Spectrometer Laboratory, Fayetteville, Ark.) or a Varian Chrompack CP-3800 GC/MS (USDA Dale Bumpers National Rice Research Center, Stuttgart, Ark.) with injection temperature at 200В°C, initial oven temperature = 50В°C for 1 minute, ramp rate of 10В°C per minute to 280В°C and hold 4 minutes.

      It was hypothesized that a lure charged with both the Mix-M floral odor mixture and a mixture of volatiles produced by fermenting peach plus cyclohexanecarboxylic acid would improve trap catch of GJB adults.

      In 2005 in Hindsville, Ark., we compared two mixtures for attractiveness to GJB adults. TRE#8706 was a mixture designed after Mix-M that contained: 0.82 gm phenylacetaldehyde; 0.84 gm (R)(+) limonene; 0.79 gm 2-phenylethanol; 0.36 gm methyl salicylate; and 0.7 gm methyl-2-methoxybenzoate.

      TRE#9722 was our GJB headspace volatile mixture that contained: 2.79 gm (R)(+) limonene; 0.25 gm 2-phenylethanol; 0.42 gm methyl salicylate; and 0.04 gm methyl-2-methoxybenzoate.

      Both mixtures were provided by TrР№cР№ Inc., Adair, Okla. The lower funnel opening of several yellow Japanese Beetle (JB) Jumbo traps was enlarged to accommodate GJB adults. These modified JB traps were placed in a field adjacent to a grape planting containing ripe fruit.

      Each trap was baited with a TrР№cР№ floral lure cup dispenser containing 3.5 ml of either mixture TRE#8607 or TRE#9722. Traps were arranged in a RCB design with three replicates. From July 15 to Sept. 1, 2005, a total of 1,298 GJB were captured in the TRE#8607 baited trap compared to 178 GJB in traps baited with TRE#9722. Thus, something was missing from our GJB mixture TRE#9722.

      In 2006, we compared a series of odor mixtures for attractiveness to GJB adults. All tests were conducted in a field adjacent to a planting of ripe nectarines and peaches in Bethel Heights, Ark. Traps were arranged in a RCB design with two or more replicates. Brown, 25 ml bottles were filled with 4 ml of a mixture, not capped and hung by a wire inside the trap capture pail.

      Nitidulid mixture had both an aqueous and oil mixture: 50 ml water + 11.4 ml ethanol + 38.5 ul acetaldehyde + 3.1 ul 2-methyl-1-propanol + 6.87 ul 3-methyl-1-butanol (isoamyl alcohol) + 1.36 ul 2-methyl-1-butanol; and 50 ml mineral oil + 0.066 ul ethyl acetate + 0.0115 ul ethyl caprylate (ethyl octanoate) + 0.0115 ul ethyl caproate (ethyl hexanoate) (described by Bartelt and Hossain, 4).

      GJB mixture also had both an aqueous and oil mixture: 50 ml water + 36.7 ul phenylacetaldehyde + 36.7 ul 2-phenyl ethanol + 36.1 ul benzyl alcohol + 40.3 ul hexanoic acid; and 50 ml mineral oil + 42.8 ul 3-methyl-butyl acetate (isoamyl acetate) + 36.3 ul cyclohexanecarboxylic acid ).

      500X GJB mixture was modified to include a more concentrated mixture of ingredients: 100 ml ethanol + 1ml acetaldehyde + 1 ml ethyl acetate + 1 ml 3-methyl-1-butanol (isoamyl alcohol) + 1 ml cyclohexanecarboxylic acid + 1 ml 3-methyl-butyl acetate (isoamyl acetate) + 1 ml hexanoic acid + 1 ml 2-phenyl ethanol + 1 ml 2-phenylethyl acetate + 1 ml phenylacetaldehyde.

      The addition of the Nitidulid mixture to Mix-M mixture significantly increased the GJB trap capture compared to Mix-M alone on July 20 or the natural attractant of GJB feeding on peach or GJB mixture or 500X GJB mixture of peach volatile which were all similar on later dates.

    • Grape Root Borer

      Season total pheromone trap catches more than doubled from 2005 to 2006. In Missouri vineyards in Ste. Genevieve, there were 31 and 65 GRB moths per trap in 2005 and 2006, respectively. In Hermann there were 11 and 130, and in St. James there were 8 and 34 compared to 5 and 33 in Hindsville, Ark.

      Survey of 100+ vines per vineyard in late August resulted in low GRB pupal skin counts in Missouri: Ste. Genevieve (4 skins), St. James (1), Rocheport (0); and in Arkansas: Altus (1) and Hindsville (0).

      Grape phylloxera (GP) were observed in most demonstration vineyards. More research is needed on GP in the Ozark region. Therefore, a two-year grant proposal was submitted to the Missouri Grape and Wine Board Research Committee that has three objectives:

      1. To derive an economic threshold by regressing the impact of a series of geometric treatment increases in initial infestation rates of foliar grape phylloxera to grapevine performance (yield, juice quality, pruning weight and return bloom).
      2. To compare and demonstrate spray and timing effectiveness of Thiodan against grape phylloxera to that by new formulations of Assail®, Admire Pro® and Danitol®.
      3. To survey and rank infestations of foliar and root grape phylloxera on the major wine grape cultivars growing in the Ozark Mountain Region as self-rooted or grafted on rootstocks.

      Results for the first year of that project are reported under the title of the project: Control and Survey of Aerial and Root Grape Phylloxera on Grape Cultivars.

      At field workshops, growers were trained to make decisions about managing grape insect pests by monitoring pheromone trap catches for GBM, GRB, JB and GP.

      Tables of pest trap counts were updated weekly or as data were received from growers or scouts and available on the Internet at:

      Temperature and rainfall (daily and cumulative) data were downloaded for each of the four vineyards in Missouri from the University of Missouri Extension. Spectrum Technologies Watchdog weather stations were in each vineyard in Missouri and Arkansas to allow for an end-of-season comparison of in-vineyard weather station temperature data to that of the nearest County or region temperature data provided by the University of Missouri Extension and the Arkansas Cooperative Extension Service.

      The regional temperature data for Clarksville, Ark., that was used for the Altus vineyard site (10 miles apart) came from the Arkansas Cooperative Extension Service.

      Graphs of cumulative daily DD for GBM were available for all six vineyards on the Internet. Arkansas data was used to generate graphs of cumulative DD for GBM development.

      Missouri data was used to generate graphs of cumulative DD for GBM development.

Objective 4: To produce a Wine Grape Integrated Production Systems Workbook for use in grower grape best management practices workshops.

  • A meeting of the principle participants in this project was held in September to discuss subject matter and format for the workbook. This workbook will be composed during the winter of 2006 to 2007 for use in the 2007 season.

Dissemination Activities

Dissemination of information is a key objective of this project and in 2006 was accomplished through the use of a Web site and the vineyard field workshops in March/April, May, June and July. A season wrap-up meeting was held in December 2006 at four of the locations.

Detailed data may be obtained by contacting:

MaryLou Dumbleton
Jordan Hall
NYSAES/Cornell University
Geneva, NY 14456
Phone: 315-787-2290
Fax: 315-787-2276
E-mail: mld2@cornell.edu

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