Southwest Michigan Horticultural Days held this past February at Lake Michigan College had over 45 different exhibitors. Attendance showed an increase, and programming included sessions on vegetables, farm labor, tree fruit and grapes. The Hospitality/Wine Tasting held at the Ramada Inn, in Benton Harbor was attended by many and representatives from the Michigan Grape and Wine Industry Council.

The Michigan Grape Society held their meeting on the second day of the show . President, Ed Kerlikowske opened the meeting and appointed tellers for the election and a secretary to fill in for the meeting. A survey of those present was taken to see if they had received their MGS Newsletter. Some members had not. MGS said they would improve distribution of the newsletter.

Linda Jones, Coordinator of the Michigan Grape and Wine Industry Council was introduced and then thanked the Grape Society and MSU Extension for their efforts. She gave an overview of the Council which is a ten member body that is appointed by the legislature that represents all segments of the grape and wine industry. One of the items they focus on is research and other items supported by the Council are promotions of wine grape sales and to look at obstacles of growth such as urban sprawl and township zoning. She requested that growers fill out the Michigan Ag Statistics survey because it is a tool they use to survey growth and obtain funding

Results of the Michigan Grape Society Election were, Mark Gregory and Tim Seppala elected Directors and Joe Herman and Mike Hildebrand, Associate Directors. Marketing representative elected was Tom Tapper and Associate was Richard Haynor.

The two big winners at the Southwest Michigan Horticulture Show were Will Pugsley from Lawrence Michigan who won the Amway Grand Plaza weekend get-away and Art King, from Baroda, Michigan won the Amish Acres Bed/Breakfast giveaway.

11th Annual Viticulture Field Day
And Steak Cookout
By: Tom Zabadal, SWMREC Coordinator

Dr. Jeff Andresen runs the MSU Agricultural Weather Office. Jeff received a GREEEN grant to set up a system of automated weather stations in Michigan. The hope is that growers and consultants can use the Internet to access current weather data. Another thrust is to develop disease models that will predict infection periods for plant diseases. The grant gave Jeff the ability to hire a technician to service and repair the weather stations but not enough money to buy weather stations. Each weather station costs about $5000. Jeff has been busy acquiring existing weather stations to incorporate into his system. Public entities or private corporations usually buy the stations. Usually Jeff will make an agreement to maintain the weather station in return for being able to post its weather data on the Internet.

Disease control drives the pesticide program in grapes. Disease control in the early season is crucial. The focus is on preventing the diseases from becoming established in the vineyard. Mid and late season eradication is almost impossible once the diseases become established and substantial fruit loss to rots or fruit drop may result.

Early season control is focused on Phomopsis, Black Rot and Powdery Mildew. The EBDC materials provide excellent protection against phomopsis, black rot and powdery mildew. Most growers try for 2 or 3 EBDC sprays before bloom. These sprays are timed for application before a rain with an EBDC alone or after a rain if used in combination with a SI fungicide. The SI materials provide excellent control of black rot and powdery mildew and good control of phomopsis. The SI materials have about 3 days of back action against these diseases. The EBDC fungicides are not allowed by National Grape after bloom begins and Captan is not allowed at all. Phomopsis is a problem especially in Niagara. It causes fruit drop in the late season.

The bloom sprays are probably the most important sprays for disease control. Downy mildew becomes a problem at bloom. A final EBDC spray is timed for immediately preceding bloom, to control this disease. The SI fungicides do not control downy mildew. Ridomil provides excellent control of downy mildew as an eradicant and was used for that until Ziram was labeled in grapes. Ridomil has a 66-day PHI. The SI fungicides (Nova, Bayleton, Rubigan and Procure) have been used alone in the post bloom period for over 15 years and several diseases are becoming resistant. A tank mix of Ziram and a SI is used in the post bloom period with about 14 days of control. The new strobilurin (SU) fungicides Abound and Sovran are used in rotation with the SI tank mixes. These materials provide control against all the major grape diseases except Botrytis. Abound is better than Sovran against downy mildew. The strobilurins have about 3 days of back action.

Both mildew diseases can become severe in the summer if they are established early. Warm humid days with heavy dews will quickly spread the disease through a vineyard.

Climbing cutworm are controlled in the early spring at budbreak with Lorsban 4E, which has a Special Local Needs (24c) label.

Insecticides are applied with the bloom sprays to control the first generation of berry moth and rose chafer. This insecticide application is also used again after bloom to control grape berry moth, Japanese beetle and grape leafhopper. Lots of Lannate is used because it is cheap and effective. Grape leafhopper is becoming resistant to Sevin. Provado provides excellent long-term control of grape leafhopper and is fair against Japanese beetle and rose chafer; but it provides no control of grape berry moth. Many growers will use Provado to control leafhopper and then try to time organophosphate sprays for grape berry moth, rose chafer and Japanese beetle. Timing of insecticide sprays for grape berry moth is very difficult. Check my code-a-phone (657-6380) for updates on grape berry moth catch. Pheromone disruption of this pest shows some promise, but pheromone disruption should probably be combined with insecticide sprays.

The photo at the right was submitted by Jacques van den Hombergh, from Hartford, Michigan. The picture was taken over 20 years ago and published in a magazine by Welch’s.

As you can see the picture is old, but Jacques van den Homberg is shown standing beside a row of grapes in the plastic structure which he used to enclose slightly more than a half acre of his vineyard. There are also some 800 tomato plants in the lower right hand corner of the photograph.

On May 10, twenty years ago, the temperature was 19 degrees and a 52 mile an hour wind blew down a section of the structure. There was also a large blower blowing heat under the structure. There was no damage to the grapes or tomatoes. That year he sold all the grapes on the fresh market and also the early tomatoes.

In the past year, grape growers have lost a long-used tool for the management of insect pests, and have recently gained a few new ones. As a companion to the season-long pest management guide presented in this newsletter, these changes will be described in detail below. Now is the time to think about the changes while planning your insect control program for 2000.

RESTRICTIONS

In response to the Food Quality Protection Act (FQPA), the use of methyl parathion (Penncap-M) in fruit crops was banned by EPA last year. This broad-spectrum, effective and relatively inexpensive product cannot be used on any grapes this year or in the future, and has been lost as an important tool that Michigan grape growers have relied on for years. With this change, we are left with insecticides that have a more selective range of insects they control, that have shorter residual activity, or that may be more expensive. In the future, growers will have to weigh up these properties and make decisions based on the specific mix of pests present in the vineyard during the year.

The other change affecting grape growers this year relates to the use of azinphos methyl (Guthion 50 WP). This effective insecticide is still restricted to 3 applications per year in grapes, but worker protection standards have changed so the re-entry interval (REI) is now 21 days for any activity when the plant will be touched, and 48 hours for other operations (harvesting etc). There is also now a 21 day pre-harvest interval (PHI) for Guthion in grapes.

NEW PRODUCTS

The old saying, ‘Change creates opportunity’, has certainly been true for insect management in grapes this year. A new insecticide was registered for grapes soon after the restrictions on others were announced. Fenproprathin (Danitol 2.4 EC) is a synthetic pyrethroid insecticide, now registered for use in grapes, with activity against leafhoppers, grape berry moth, and Japanese beetle. Recommended rates are 5.3 oz/acre for leafhopper, and 10.6 oz/acre for grape berry moth and Japanese beetle. Danitol has a 21 day PHI and 24 h REI. We are conducting trials in SW Michigan this year to determine the effectiveness of Danitol against cutworms and rose chafer, but these two pests are not on the current label.

Danitol should not be applied more than 1-2 times a year, because of resistance management and to conserve natural predator populations in your vineyards. Repeated use of pyrethroids has been shown to cause rapid development of resistance to this class of insecticides in the target pests, making them less effective and reducing the length of time they can be used as a management tool. Natural predators of pest insects and mites are also very sensitive to pyrethroids, and can be knocked out of the system by repeated applications. As an eminent member of my profession once stated, “When we kill off the natural enemies of a pest, we inherit their work”.

The best way to avoid these potential problems is to apply Danitol only once or twice, preferably early in the season before predator populations start to develop. Insect management programs should be planned to get control of grape berry moth and leafhoppers early in the season before they become a problem and threaten the photosynthesis of leaves and the quality of the grapes later in the year. Remember that like most broad-spectrum insecticides, any new foliage that grows after application of this product will not be protected from insect damage.

Another new product registered for grapes this year is the sprayable GBM pheromone for mating disruption of grape berry moth, and can be an effective tool in vineyards with low to moderate GBM pressure. This product is made by 3M, and it works the same way as the twist-tie mating disruption product (Isomate GBM), but it is a liquid formulation that can be added directly to other sprays and applied through standard equipment. It should be applied at 2 oz/acre at the first sign of GBM adult flight activity monitored by pheromone traps placed at vineyard edges, preferably adjacent to woods.

Pheromones work very differently from other insecticides. They reduce pest populations by ‘jamming’ the communication between male and female moths, so that they cannot find each other, and then do not mate. It’s like applying a ‘fog’ to the vineyard, and the male moth can no longer see the female’s ‘smoke signals’. When mating is reduced, fewer eggs are laid, and fewer berry moth larvae are in the fruit. This product must be applied against a generation of GBM immediately when adult moths are caught in pheromone traps, so regular trap monitoring will help with this decision. It is better to be a little early with this product than one day late.

If considering this product as part of your management program, be aware that mating disruption works well in some vineyards, but cannot do the job alone in vineyards with history of GBM or with wooded borders around the vineyard. Supplemental insecticides may be required if initial populations of GBM are too high or if mated females are flying in from outside the treated vineyard. In these situations, a well-timed insecticide spray for the first generation of GBM will provide a more manageable population for the pheromone to disrupt in successive generations. Monitor for GBM twice a week with more than one pheromone trap in your farm, and with routine inspection of foliage and fruit. This will help growers and consultants decide whether population buildup is occurring and how well the product is working.

SUMMARY

The insecticide picture continues to develop for grape growers, and future restrictions will undoubtedly change the rules for the products currently in use. New products are being developed however, and we are working at MSU to test them and determine which of the potential future insecticides have an appropriate place in your grape pest management program.

Heartland Wine School will be June 5-7, 2000. Ohio State University, in cooperation with the Heartland Grape and Wine Coalition, is sponsoring the enology meeting, which will be held in Columbus, Ohio. The program will cover all aspects of wine making from harvest to bottle with 15 speakers from several universities, wineries and commercial enology companies.  Registration for this event is $250. For detailed information on this program, registration, lodging, etc. contact Tom Zabadal at 616-944-1477 x 200.

There are times when a grower needs to make a pesticide application to a vineyard and there's an approaching storm. Is there enough time to put that spray on and have it dry before the storm actually arrives? Satellite and radar weather information can be very helpful in such instances because frequent (15-minute interval) updates to cloud and storm patterns can give the grower a fairly accurate prediction of his spray window of opportunity. Some very nice services provide this type of information for a fee. There are also numerous weather data sources available without charge if one has access to the internet. One of the web sites that provides a 4-segment-per-hour weather loop that can be used to view weather movement in the southwest Michigan area over the past six hours is:

http:www.intellicast.com/LocalWeather/World/UnitedStates/Midwest/Ohio/Dayton/RadarLoop

Yes indeed, that is quite a mouthful and one must be sure to type in that web address exactly (including capital letters where needed). However, after entering that web address once, it can be saved to your "favorites" or bookmarked in your internet browser so in the future you can just click on it.