There will be two grape sessions at the Great Lakes Fruit, Vegetable & Farm Market EXPO in Grand Rapids December 6-9. The grape session will be Tuesday afternoon on December 6. The talks will address changes in pesticides and cultural practices.

Dr. Rufus Isaacs will report on the Grape IPM program that is being evaluated in Michigan vineyards. This program compares a scouted vineyard where soft insecticides are being used with another “grower standard” vineyard where the grower uses his standard spray program to control insects. As older insecticides are being phased out of agriculture, newer softer materials are registered to take their place. The mode of action of the newer insecticides is different than insecticides and in many cases the new materials control group of insects but have little impact on other insects in the vineyard. Control will differ between different materials and insects that are not pests may increase and become pests.

Dr. Mike Ellis has spoken to Michigan fruit growers about disease control several times and his talk will point to the critical control windows for applying fungicides to grapes. In 2005, a dry growing season reduced disease pressure and loses to disease. Dr. Ellis’ talk will focus how effective certain fungicides are in controlling diseases and the timing required to get the most of your fungicide spray dollar.

Dr. Tom Zabadal, from SWMREC (Southwest Michigan Research & Extension Center) will discuss the different ways that growers can increase vine size. One way to increase yields is to increase the amount of fruiting wood that the vineyard can sustain year after year.

Great Lakes Expo-Grape Session, Tuesday December 6, 2-4 pm
Evaluation of Insect IPM programs in Michigan Grape Vineyards, Dr Rufus Isaacs, MSU Department of Entomology
Critical periods for applying fungicides to grapes, Dr Mike Ellis, Ohio State University, Department of Plant Pathology
Techniques to Increase Vine Size, Dr. Tom Zabadal, Southwest Michigan Research & Extension Center
Reducing Asian Multicolored Ladybug in Michigan Vineyards, Dr. Rufus Isaacs, MSU Department of Entomology

A year ago, if you had told me that 2005 would be a drought year, where blueberries would burn up in the field, but grapes would have both excellent yields and quality and almost no disease pressure, I would have doubted it. Now having seen it, I believe.

The summer of 2005 was a long string of hot cloudless days that were almost perfect for grapes. During the summer, I was reminded of the growing conditions out west. These were the kind of conditions that growers in the western pool have in Eastern Washington every year. If every year in Michigan was like 2005 then irrigation would almost be required to grow most crops such as grapes, vegetables and tree fruit, it would even be common in field crops.

There was another blessing of the dry conditions and that was that we had very light disease pressure. Lake Michigan suppressed rain almost from the beginning of the growing season. There were only a few spring rains. This meant that if growers had good control of grape diseases early then there was little chance for diseases to develop later in the year. I was amazed that we saw very little downy mildew. I have become accustomed to seeing downy mildew increase all summer long but not this year. Annemiek Schilder writes in her article about how the dry conditions were poor for disease development but another advantage to having low disease pressure is the leaves are healthy and productive.

If the dry conditions suppressed disease development they did not seem to do much about insects. Grape berry moth and Japanese beetle were still a problem but grape leafhopper was scarce all year and I do not know why. Grape berry moth continues to be the insect that drives the grape insecticide program. The more I try to understand and control this pest the more I wonder if there is any easy way to control it. Several well timed sprays during the year seem to do the trick in some years and other years, it seems that there is a huge rush of moths just before harvest and the only way to control it is to spray as often as you can and I know that is not a profitable way to control this pest.

Hard Cider Workshop at Cornell University
December 5–9, 2005
Dr. Peter Mitchell, international consultant and authority on fermented ciders and parries, will conduct hands-on workshops in the Vinification Lab in Geneva, N.Y. Contact Dr. Ian Merwin at Cornell at im13@cornell.edu for more information. Dr. Merwin’s website is www.hort.cornell.edu/department/faculty/merwin/index.htm

Federal Disaster Assistance for Vineyard Losses
After the wine grape losses in 2003 in the NW, the Grape and Wine Council conducted a seminar in Traverse City in February 2005 to help growers understand the mechanisms to apply for federal disaster assistance in poor years. The Grape and Wine Council, through MDA Director Mitch Irwin, also assisted growers in getting appropriate price guidelines for vinifera wine grape varieties that will be used to pay disaster claims. Wine grape growers are urged to register their vineyards with the Farm Service Agency of USDA as soon as possible, to start building the yield and price history for their operations that will form the basis of any future claims. Regional offices are listed in the blue

Agricultural Statistics – Info on Grape Industry Needed
The Michigan Field Office of the National Agricultural Statistics Service (NASS) Division of USDA will be conducting its fall/ winter surveys of grape growers and grape processors (wineries and juice processors). This information is published on the NASS website which is accessible from www.michigan.gov/mda Click on Statistics and Resources button on the left side of the home page.

General observations
In contrast to the cool rainy summer of last year, 2005 was extremely dry and warm. Drought conditions were serious in the western and northern parts of the state and even affected fruit quantity and quality. The good news was that the dry weather was not very conducive to diseases, therefore fewer fungicide sprays were needed and fruit quality was generally better than in previous years. In general, cool, wet years like 2004 promote fungal and bacterial disease development, whereas hot, dry years tend to increase insect pest pressure (e.g., grape berry moth). Most fungi and bacteria need free moisture in the form of rain or dew to grow and infect plants, and often also for spore production and dispersal. The lack of precipitation definitely thwarted pathogen activities. The only fungi that were content without rain were the powdery mildews, which were quite common on numerous crops this year. Diseases that resulted from infections in previous years, e.g., cane diseases and virus infections, were evident but were obviously not related to the weather in 2005.

Grape disease situation
Due to the warm, dry summer, diseases were less of a problem in grapes than in previous years. Phomopsis cane and leaf spot (caused by the fungus Phomopsis viticola) was found in many vineyards, but infection pressure was generally low. Clusters that were left hanging for a long time developed rachis and berry infections, but incidence and severity were much lower than in previous years. Black rot (caused by the fungus Guignardia bidwellii) was also detected here and there, but both incidence and severity were much lower than in previous years. For example, in untreated areas of our ‘Concord’ research plot at the Trevor Nichols Research Station in Fennville, black rot affected only about 3% of the berries, compared to 60% of the berries in 2004. So a 95% reduction in disease due to the weather alone!

Powdery mildew (caused by the fungus Uncinula necator) showed up later than expected, considering that we had moderate to high relative humidity during most of the season. However, rain is needed for the initial release of ascospores to get the epidemic started, and it is possible that the lack of precipitation could have delayed or diminshed spore dispersal. In addition, high temperatures (in the 90’s) tend to shut down powdery mildew development and we did reach these temperatures on numerous occasions. Powdery mildew was eventually found on a few berries in ‘Concord’ grapes but this level of disease was not of concern. By the end of the season, powdery mildew was visible on ‘Concord’ and Niagara’ leaves in some vineyards. However, it occurred late enough to be of little consequence to yield or fruit quality. Infections of leaves and clusters were noted in susceptible wine grapes.

Downy mildew (caused by the fungal-like organism Plasmopara viticola) on grape clusters and leaves showed up late, and severity was generally low. Dew in August and September may have helped to move the disease along, but negative effects were minimal. Yellow spots observed on leaves earlier in the season (June/July) were not downy mildew but most likely caused by small herbicide (e.g., Chateau, Gramoxone) droplets that drifted into the canopy. While the symptoms looked somewhat alike, these spots never developed white sporulation on the back.

Anthracnose (caused by the fungus Elsinoë ampelina) appeared on some wine and table grape varieties (e.g., Marquis, Mars, Vidal) that had the disease last year. However, lesions showed up later than normal, and were less severe and mainly restricted to the leaves, canes, and tendrils. Since fruit infections are most important economically, these did not have much of an effect on the current crop.

Some apparent Botrytis (caused by the fungus Botrytis cinerea) infections of clusters (tip necrosis) were observed soon after bloom in a few wine grape vineyards, but in general, fruit quality has been excellent this year. Botrytis infections were commonly seen in berries that were infested with grape berry moth, but considered secondary since wounds made by the berry moth larvae predispose the berries to infection.

Eutypa dieback (caused by the fungus Eutypa lata) symptoms (leaf cupping, yellowing, and stunting of shoots) were fairly obvious in spring and early summer. However, these infections probably occurred years ago. Interestingly, foliar symptoms, which appear to be caused by a toxic substance produced by the fungus in the wood, do seem more severe during years with cold springs in which shoot expansion is slowed considerably, possibly allowing the toxin to do more damage to shoot tissues. While the weather was relatively warm after budbreak, there was a cool period in late April/early May which may explain the clarity of Eutypa symptoms.

Conclusion
The warm dry year aided grape growers tremendously with disease control, so then they were left to battle insects! While stretching fungicide spray intervals may have made some growers nervous, this past season would have been ideal for a reduced spray schedule combined with field scouting and possibly a dormant sulfur or copper application. The other benefit of a dry year is that inoculum levels for next year’s epidemics will be reduced.

Insecticides
Baythroid (cyfluthrin) is a pyrethroid insecticide registered for control of a broad spectrum of insect pests. We have had little direct experience of this product in Michigan vineyard trials, but expect it to be active on many key pests. This material is toxic to mite predators and should be used carefully to prevent mite population buildup. Baythroid 2E is restricted to 2 applications per year and a total of 2.8 oz per season. 3 day PHI.

Venom (dinotefuran) belongs to the neonicotinoid class and is registered on grapes as a 20 SG for the control of leafhoppers, thrips and mealybug at 0.44-0.66 lb/acre. This locally systemic material has long residual inside the foliage, and because the residue is quickly absorbed into the plant, negative impact on natural enemies is minimized. Do not apply more than 1.32 lbs of Venom 20 SG per acre pre season. 1 day PHI.

Miticides
Acramite (bifenazate) belongs to a new class of miticides called carbazates. It is a contact miticide that is primarily active against motile stages of European red mite and two spotted spider mite, but also nymphal stages that hatch after application. For best performance maintain spray tank water at or near pH 7.0. 14 day PHI.

Envidor (spirodiclofen) is a miticide labeled for use in grapes, pome fruits and stone fruits for control of the European red mite and two-spotted spider mite. Envidor is part of a new chemical class called tetronic acids, and has a novel mode of action characterized as a lipid biosynthesis inhibitor (LBI), and is active by contact to all life stages. Envidor 2SC is restricted to one application per season, and 20 fl oz per acre per year, for all labeled fruit crops. 14 day PHI.

FujiMite (pyridaben) is an insecticide/miticide registered that works as a contact miticide/insecticide providing good knockdown and residual control of mites and leafhoppers, and should be applied when pest populations are beginning to build and before they reach economic thresholds. It is effective on a broad spectrum of mite pests, but requires thorough coverage to ensure pests will contact the product. FujiMite 5EC is restricted to two applications per season, and a total of 2 pints per acre per year. 14 day PHI.

Nexter (pyridaben) (used to be Pyramite) is an insecticide/miticide that acts as a contact miticide/insecticide that provides knockdown and residual control of mites and leafhoppers and should be applied when pest populations are beginning to build and before they reach economic thresholds. It is effective on a broad spectrum of mite pests, but requires thorough coverage to ensure pests will contact the product. 7 day PHI.

Wine Grapes Session, Great Lakes Expo Wednesday 9:00-11:00 a.m.

9:00 a.m. Developing a Relationship Between a Distributor and Your Winery, Tom Zuiderveen, Kent Beverage Company
9:20 am –11:00 a.m. Michigan Wine & Grape Council Research Reports
Integrating and Optimizing IPM into Michigan Vineyards, Dr Rufus Isaacs, MSU Department of Entomology
IR-4 Screening of New Insecticides for Grapes, Dr. John Wise, MSU Department of Entomology
Crop Estimation, Evaluation of Viticulture Cultivars, Evaluation of Training Systems, Dr. Stan Howell, MSU Department of Horticulture
Utilizing GIS in Michigan for Vineyard Site Selection, Dr Jeff Andresen, MSU Department of Geography
Eliminating Crown Gall from White Vinifera Clones, Dr. Tom Zabadal, SWMREC, MSU
Anthracnose in Michigan Wine Grapes, Dr. Annemiek Schilder, Plant Pathology Dept. MSU
Reducing Bell Pepper Characteristics in Red vinifera Wine , Dr. Stan Howell, MSU Department of Horticulture

Call you local Extension office for more information