Grape berry moth (GBM) - eggs were found again this week on Concord berries in a border row next to the woods at a severe risk site. Berry injury caused by GBM feeding was also easy to find but injury levels are lower compared to last season. This indicates that the potential exists for high injury levels to occur on border rows at sites with historical problems with GBM. Continue to scout your high risk sites but be aware that recognizing GBM feeding injury becomes more difficult as Concord berries continue to color. At this point in the season, look for entry holes in berries, split berries and berries that are webbed together.

If > 15% injured clusters are observed then apply an insecticide to border areas. Achieving good coverage is difficult this late in the season so increase gallonage if needed and slow down during application. Also be aware of preharvest intervals of any insecticides used.

Pennsylvania Grape Growers may be eligible for IPM, cover crop, or nutrient management payments through the Environmental Quality Incentives Program (EQIP) from the Natural Resources Conservation Service (NRCS). The deadline to be considered for the first round of allocations is November 30, 2007. However, growers are encouraged to send applications to their local NRCS office as soon as possible so that fund allocations will reflect local interest in the program. This will also allow adequate time for field visits and updating Conservation Plans and other records.

For more information contact the Waterford NRCS office at 814-796-6760 ext. 3 or e-mail jody.lasko@pa.usda.gov. EQIP application form is also available on-line at: http://www.nrcs.usda.gov/PROGRAMS/EQIP/PDFs/EQIP_Program_Application_and_Appendix.pdf.

For additional information on EQIP, feel free to visit our website:    http://www.pa.nrcs.usda.gov/programs/eqip/index.html.

Weather:
The last two weeks have seen a lot of wet weather. At our location, we have accumulated 5.75 inches of rain so far in August (almost half of which fell on Monday, August 20). Our gdd accumulation since April 1 totals 1896 through August 22.

Diseases:
Dry weather for four weeks after bloom left the vast majority of vineyards relatively free of black rot (and just about everything else) this year. However, ample precipitation and long wetting periods from 4-6 weeks after bloom (second half of July) provided conditions for several major black rot infection periods. Was this anything to worry about? In vineyards with little over-wintering inoculum (thorough application of effective materials last year, good site) and where critical fruit protection sprays were timely applied this year, these late infection periods did not present much of a problem with respect to this disease. But in vineyards with high inoculum loads from build up of black rot in previous years, the late July weather provided the opportunity for significant levels of black rot fruit infection to develop in some vineyard blocks (about 2-3 % crop loss equals the cost of an extra spray). Inoculations suggest that Concord fruit clusters were very susceptible to black rot for at least 3-4 weeks after bloom this year. We started to detect some development of resistance between 4 and 5 weeks post bloom, but it was not until the inoculation at 6 weeks post bloom (last week in July) that we really observed susceptibility plunge to near zero. Disease assessments in unprotected research and commercial blocks with over wintering inoculum revealed that the vast majority (90 %?) of infected berries in these hardest hit areas and plots (some with as much as 27 % crop loss) are at rot stages matching those inoculated from 4-5 weeks post bloom. This serves as a reminder of the long fruit susceptibility period for black rot, even on Concord (longer than all other diseases of juice grapes) and the importance of exerting tight control of over wintering inoculum sources, especially in ‘high risk’ (vineyards where air drainage and evaporation is poor) and/or organically managed vineyards. Most vineyards had little over wintering inoculum and even less current season inoculum for the disease to build on, and in these areas fungicide sprays for black rot control on juice grapes were safely concluded after the second post bloom spray with minimal economic consequence from late infection periods. Where over wintering inoculum had built up (lots of infected canes, mummies in the trellis), the threat of economic consequences from infection periods beyond 4 weeks post bloom was very real.

With the continuation of wet conditions for the last several weeks, we are now starting to see downy mildew lesions beginning to show up on Niagara leaves. Their presence is almost entirely confined to young leaves on or near the ground (uncontrolled sucker growth, overly long or continuously growing shoots from excessive fertilization and/or vigor).

Bunch rots are developing on tight cluster wine varieties like Vignoles, Riesling, Pinot gris etc. If conditions continue to stay on the wet side, we could see more than just Botrytis move in. Sour rots, both fungal and bacterial are of more serious concern to juice quality than Botrytis and there are no effective pesticides for their control. This is where cultural controls come in. Leaf pulling in the cluster zone offers tremendous advantages in the control of sour rots. No one can control the weather, but, through cultural treatments and proper trellis construction that open the cluster zone and reduce cluster compactness, growers can limit the influence of the weather on bunch rot development and ensure more consistent wine quality in spite of the weather.