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Michigan Grape & Wine Industry Council 2012 Research Report

Michigan Vineyard IPM Scouting Program

Rufus Isaacs1, Steve Van Timmeren1, Diane Brown-Rytlewiski2, Annemiek Schilder3, Duke Elsner2,

Paul Jenkins1, and Beth Bishop1 1. Department of Entomology, 2. MSU Extension, Michigan State University. 3. Department of Plant Pathology, Contact isaacsr@msu.edu, for more information on this project. ABSTRACT This project has demonstrated that reduced-risk pesticides can be successfully integrated into commercial grape production while maintaining effective pest control and in some cases improve pest control compared to broad-spectrum pesticides. In addition, the use of regular insect and disease scouting along with degree day models allows for better timing of pesticide sprays and a reduced number of unnecessary sprays. An electronic newsletter was published regularly through the growing season. This newsletter contained current scouting information from southwest and northwest Michigan as well as timely articles on topics ranging from grape berry moth control to crop estimation and frost protection. Several grape workshops were held in southwest and northwest Michigan during the growing season as well. These workshops provided information on current insect and disease topics as well as sprayer calibration and spray deposition. Presentations at winter grower meetings reinforced the information delivered during the summer. GOALS & OBJECTIVES This project aims to demonstrate IPM techniques to the Michigan grape industry using a combination of formal presentations and hands-on demonstrations. This includes insect and disease scouting to provide timely information for determining if and when to spray as well as sprayer demonstrations to maximize pesticides that do have to be applied. Objectives: 1. Demonstrate performance of scouting and reduced-risk management in commercial grape vineyards. 2. Deliver information on IPM and cultural controls to the Michigan grape industry. 3. Deliver training programs on sprayer calibration and vineyard spraying in 2012. RESULTS & CONCLUSIONS This project has supported the delivery of relevant and timely information to the grape industry regarding vineyard management. It has also supported the gathering of weekly scouting information used to present timely updates and recommendations in the Michigan Grape & Wine Newsletter published by Paul Jenkins and MSU Extension. The scouting information has also been taken at vineyards where reduced-risk insect and disease management programs have been used, and this has allowed demonstration of their efficacy under commercial conditions, resulting in improved pest control and reduced dependence on broad-spectrum pesticides. During 2012 we

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also organized and delivered several workshops covering insect and disease-related topics as well as sprayer calibration vineyard spraying. OUTCOMES Growers have been able to see the performance of new pest management programs at commercial scales and the sites have provided venues through the growing season for discussion of relevant issues in the plant pathology, entomology, and horticultural realms. Our ongoing extension program has helped improve vineyard management in Michigan and we have had highly positive feedback from growers on the information being provided. Feedback from growers at post-harvest meetings indicate increasing adoption of certain reduced-risk products such as Intrepid into spray programs, as well as an increase of the use of scouting to determine if sprays are necessary and the grape berry moth degree model to time sprays. PROJECT PERIOD This project was conducted during 2012 as a continuation of this extension project. WORK ACCOMPLISHED DURING THE PERIOD Objective 1. Demonstrate performance of scouting and reduced-risk management in commercial grape vineyards. The integration of reduced-risk pesticides into the management programs of the demonstration vineyards in this study show these products can be used successfully in a commercial setting. Reduced-risk products have consistently performed as well as their conventional counterparts and at no point did the use of reduced-risk products cause unacceptably high levels of insect or disease damage. In fact, in some cases the reduced-risk products have consistently outperformed their broad-spectrum counterparts. For example, at the Concord demonstration vineyard in Van Buren County, Intrepid has been the reduced-risk product used in a grape berry moth (GBM) control program since 2005. The corresponding conventional program has included many different broad spectrum products including pyrethroids (such as Baythroid and Brigade), organophosphates (such as Imidan), and carbamates (Sevin). The top graph in figure 1 shows how GBM-infested clusters at harvest were lower in the reduced-risk vineyard in every year since Intrepid was first used in 2005. In addition, during April and May a higher number of adult GBM were caught in traps in the conventionally-managed vineyard (Figure 1-bottom graph). This indicates that the lower level of GBM-infested clusters in the reduced-risk vineyard results in a lower number of adults emerging the following spring. Another example was the use of reduced-risk fungicides at the Vignoles demonstration vineyard in Berrien County. ProPhyt and Phostrol have been used as part of a program to control Phomopsis since 2006. The percentage of berries that were infected with Phomopsis was lower in the reduced-risk managed vineyard than in the conventionally-managed vineyard in every year since the first use of the product in 2006 (Fig. 2). Scouting in the demonstration vineyards provided growers with detailed timely information on the insect and disease pressure in their vineyards. Growers were able to use this information to determine when and how many pesticides to apply. In addition, our recent work on a separate Michigan Grape & Wine Industry Council project has shown that potato leafhopper damage to vines early in the season has a minimal impact on fruit quality at harvest. This information was used to help guide the spray program at the Chardonnay demonstration vineyard in Allegan

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County. The grower was able to ignore early season potato leafhopper damage and instead time a spray for controlling grape berry moth instead. 2. Deliver information on IPM and cultural controls to the Michigan grape industry. In 2012 the Michigan Grape and Wine Newsletter was again produced by Paul Jenkins. Scouting at vineyards in southwest and northwest Michigan took place on a Monday and the newsletter was distributed via email by the end of the day on Tuesday. In addition to current scouting information, the newsletter contained timely articles on a wide range of topics including disease and insect control and various aspects of viticulture. A total of 12 issues of the newsletter were produced in 2012 which were distribution to well over 600 people around the Great Lakes region. Also, grape workshops were held in southwest and northwest Michigan in 2012, with three workshops held in each region throughout the summer. Workshops focused on insect, disease, and vine management-related topics relevant to the time of the season (Figure 3). 3. Deliver training programs on sprayer calibration and vineyard spraying in 2012. In addition to the regular grape workshops, and additional couple of the workshops were conducted that focused on sprayer calibration, spray deposition, and effectively targeting pesticide sprays. These workshops included the use of a patternator which quantifies where pesticide liquid is being targeted (Figure 4). Also, the use of water sensitive paper placed in the canopy provided attendees with an excellent visual of where their pesticide sprays are ending up in the canopy and how to calibrate their sprayers to maximize spray coverage (Figure 5). Attendance at the workshops ranged from 20 to 60 growers depending on the region. COMMUNICATIONS ACTIVITIES, ACCOMPLISHMENTS, AND IMPACTS Results from this project have been shared during summer and winter grower meetings, including the SWMREC Viticulture Days, Great Lakes Expo, Southwest Hort Days, and the Northwest Orchard and Vineyard Show. The information was also presented in the twelve newsletters that were distributed via email through the growing season. FUNDING PARTNERSHIPS This project was co-sponsored by National Grape Cooperative during 2012.

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Figure 1. The percentage of clusters infested with grape berry moth at the end of September (top) and the average number of adult grape berry moth caught in traps from 2004 to 2012 in a Van Buren Concord vineyard receiving either a conventional or reduced-risk insecticide spray program for grape berry moth control. Use of reduced risk products in this vineyard began in the 2004 season, with use of improved timing for berry moth control starting in 2006.

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Figure 2. The percentage of grape berries infected with Phomopsis in a Vignoles vineyard receiving either a conventional or reduced-risk fungicide program for Phomopsis control.

Figure 3. A presentation about insect management at a grape workshop in northwest Michigan.

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Figure 4. Using a patternator at a sprayer demonstration workshop in northwest Michigan in 2012.

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Figure 5. Use of water sensitive paper to show spray deposition within a grape canopy at a sprayer demonstration workshop in northwest Michigan in 2012.