Crop Update - 6/14/2007
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Insects

We are seeing a decrease in trap catches for both male grape berry moth and the two leafhoppers (potato and grape). This indicates the first generation is winding down but with the warm weather I would guess that this will be a good year for grape berry moth and a multitude of secondary insects. I have not found a great deal of webbing in the clusters during my vineyard scouting but I have gotten reports of significant webbing from other high risk sites across the belt.

Take home message:  the only way to know what is going on in your vineyard is to get out and look for yourself (or have someone who has been trained and is trusted to do it for you). Basing your pest management decisions on what your neighbor, or the belt average, is doing can cost you money in wasted pesticide applications or worse, crop loss.

Weeds

Goldenrod seems to be the weed of the week as I have gotten a number of questions about it. One of the glyphosate products (Roundup, Touchdown, generics) at the higher labeled rates is your best bet in controlling this weed. Rick Dunst, manager of the Fredonia Vineyard Lab and our weed guru, suggests that ammonium sulfate (AMS) could be added to the spray tank to increase the effectiveness of glyphosate when plants are under water stress. Add dry AMS at 17 pounds per 100 gallon or use equivalent rates of liquid AMS (check label).

Diseases

Some areas across the belt received heavy rainfall this past weekend. Keep in mind that this is a critical time for protection of the crop against the four major diseases. Plan to keep spray intervals tight with no more than 14 days between fungicide applications. With rainfall being forecast for Tuesday keep in mind that it will be more important to get a spray on to continue excellent coverage even if you are closer to the 10 days than the 14.

If you have any questions please give me a call at 716.672.6830.

Timing for your next pesticide application
Now that we are through bloom or should be in the next few days for all Concord vineyards, start thinking about your next pesticide application. So far, the insect and disease situation has been low in the majority of vineyards that I have scouted from Route 5 to the escarpment. However, we are still in a critical period for management of all major diseases and a fungicide should be applied within 10 - 14 days of your immediate prebloom application. Choose fungicides that are effective against all of the major diseases (Phomopsis, black rot, powdery, and downy mildew) and don't skimp on rates or coverage (spray every row). Growers that have varieties that are susceptible to botrytis should also consider using a fungicide effective against this disease during bloom. Canopies are starting to fill in so this may be your last, best chance for excellent coverage. Refer to the 2007 New York and Pennsylvania Pest Management Guidelines for Grapes and to articles by Wayne Wilcox and Greg Loeb (in Lake Erie Vineyard Notes #4 & 5 - April & May 2007 newsletters) to determine the most effective pesticides and rates for all pests.

Weed Management
I have observed a wide range of weed management (or lack of) throughout the belt. Many vineyards have excellent weed control under the trellis and a good kill in the row middles. These vineyards will enjoy the benefits later in the season especially if the dry weather continues. Unfortunately, too many vineyards are showing poor to marginal control at this early stage in the season. Remember, weeds are very effective competitors for water and nutrients. Trying to save a little money now on weed management will cost you much more in the future (this season and next).

Insects and Diseases observed in vineyards this week include:
Grape berry moth - I have observed a small amount of webbing in clusters at high risk sites. At high risk sites an insecticide should be included in the tank mix at the first postbloom application. Scout other vineyard blocks for GBM and other pests.

Rose Chafer - small numbers of rose chafers are still being seen in vineyards. By now, with most vineyards through the full bloom period, the rose chafer threat is past. However, vineyard blocks with a history of this pest or blocks in bloom near the lake should continue scouting to determine if an additional insecticide is needed.

Grape leafhopper - only a small amount of stippling was observed. No sprays specifically for GLH should be needed at this time but continue scouting for leafhopper buildups.

Powdery mildew - just starting to see small patches of powdery showing up on Concord leaves so include an effective powdery fungicide in first postbloom application. Wine variety blocks susceptible to powdery mildew should be scouted frequently throughout the season. Keep a tight spray schedule in these blocks and alternate fungicides and tank mix with sulfur (if not sulfur sensitive) to avoid resistance problems. Phomopsis and black rot - Dry weather translates into less disease. Much less phomopsis showing up compared with last season and only a few black rot lesions observed. Berries still very susceptible to black rot infections so protect clusters through this period just in case the rains begin.

Phomopsis and Black rot - Dry weather translates into less disease. Much less phomopsis showing up compared with last season and only a few black rot lesions observed. Berries still very susceptible to black rot infections so protect clusters through this period just in case the rains begin.