Recent Blog Posts
By: Maria Smith, HCS-OSU
Precipitation: Much of August has followed July, with warm, dry conditions. It has only been in the past couple of weeks that we have begun seeing a reprieve from this pattern (Fig. 1). Notably, southern Ohio has had several large storms come through, alleviating previous drought conditions (Fig. 2). In contrast, northwestern and portions of central Ohio have continued remaining dry.
Here in Wooster, we had a combined total of 4.25” of rain throughout August across 8 days of measurable precipitation. Approximately 30% of that accumulated total came from a single 1.31” event on August 28 from the remnants of hurricane Laura (www.newa.cornell.edu). Despite that event, Wooster and much of northern Ohio were still at or below the 30-year average precipitation for the month (Fig. 1).
Figure 1. Accumulated precipitation during the past 30 days (left) and accumulated precipitation departure from the 30-year average (right). Figures retrieved from https://climate.osu.edu/climate-tools/climate-maps-ohio.
Figure 2. Ohio drought monitor for 1 Sep 2020. Figure retrieved from https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?OH.
Temperature: A clear delineation between eastern and western Ohio could be made for temperature trends (Fig. 3). All but the northeast corner of northern Ohio continued July’s trend of above long-term average temperatures by 1-3 °F, while southern and western Ohio tended to be closer to average temperatures.
Figure 3. Maximum, minimum, and average temperatures during the past 30 days (top), and their respective departures from the 30-year average (bottom). Figures retrieved from https://climate.osu.edu/climate-tools/climate-maps-ohio.
In the vineyard:
Harvest has begun for several of the early-season varieties over the past couple of weeks. While we were grateful to get the rain to help stave off any potential berry shrivel from the summer drought, awaiting anymore right now seems to walk a fine line between “okay, this is fine” and “harvest that fruit now”.
The ability to wait out rain events should largely be determined around your fruit’s proximity to maturity, overall fruit quality (i.e., are the berries healthy and intact or are you noticing wounding, splitting, rot, or other issues that significant rain would worsen?), and the size of the anticipated rain event. Thankfully, the season has been generous so far in limiting disease pressure and allowing us to get to this point with overall healthy fruit. If you are new to tracking your fruit maturity and deciding your harvest date, please see our resources from Dr. Imed Dami and Diane Kinney: Fruit maturity factsheet and 2020 Fruit maturity updates - OARDC Wooster.
One concern for this fall that has recently caught my attention is bird pressure. Afterall, what would 2020 be without a real-life version of Alfred Hitchcock’s The Birds, right? Several growers have reported much higher than normal bird pressure and damage over the past couple of weeks. Indeed, I observed this myself during our first harvest with ‘Marquette’ last week where robins were seen trapping themselves up and under the fastened bird netting. The concern, of course, is both in yield loss and in creating wound sites for sour rot and Botrytis development. If you are in search of options for bird control, check out this comprehensive factsheet from UNH: https://extension.unh.edu/resources/files/Resource001797_Rep2514.pdf. In general, we advocate netting as the most traditional, reliable control method. However, we recognize that different operations have different limitations, and there are various methods on the market that are worth exploring.
Lastly, if you are planning for new vineyard plantings, now through October is an ideal time to get underway with vineyard site preparation. This includes tile installation, soil decompaction, plowing, weed control, pH and some nutrient amendments, and sowing ground cover. The soil is still very warm from the summer heat, but the cooling days should bring about higher soil moisture, which makes for easier cultivation and sod establishment.
With the aim to increase grape acreage across the state, the Vineyard Expansion Assistance Program (VEAP) is back and available to new and existing growers in Ohio!
Thanks to the support of the Ohio Grape Industries Committee, new and existing growers are eligible for up to $3000 per acre with a maximum of three acres or $9000. All applicantions must be postmarked by September 23, 2020 in order to be eligible for consideration.
Please click the following link ("2020 VEAP Application") below to find a copy of the full application. If you are unable to view this link and would like a copy, please email Maria Smith at email@example.com.
For any questions for related to the application itself or the VEAP process, please contact Christy Eckstein, Executive Director of the Ohio Grape Industries Committee at firstname.lastname@example.org.
By Maria Smith, HCS-OSU
Veraison, or the onset of ripening, marks the home stretch of the growing season (Fig. 1). At this stage, berries change colors, soften, and swell with water and sugars. During ripening, vines are heavily taxed by the fruit’s carbohydrate, water, and nutrient demands. In the case that one or more of these 3 vine resources are limited, both fruit maturity and vine vegetation can visibly suffer.
Fig. 1 Early veraison indicated by color change from green to red in Marechal Foch. July 27, 2020.
While this growing season hasn’t been as stressful for disease management as 2018 and 2019, we have had notably dry weather over more than a 2 month stretch. This has brought about “abnormally dry” to “moderate drought” conditions that now cover nearly 85% of the state (Fig. 2). For young vines, this has driven a need for irrigation throughout this growing season to aid in establishing root systems and canopy growth, and for both young and mature vines, a need to keep a closer eye on changes to vine nutrient status (Fig. 3).
Fig. 2: Drought conditions for Ohio, as of 7/30/2020 (source: https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?OH)
Chlorosis in basic terms means a yellowing of leaves due to the loss of chlorophyll (the molecules responsible for light absorption during photosynthesis). Several reasons may explain chlorosis, including nutrient deficiency and drought stress. Visual symptoms aid in detecting acute issues with the vine, but ultimately for remediating nutrient deficiencies, vine nutrient status should be assessed to determine whether and which deficiencies are the exact cause.
Why vine nutrient status? Soil testing is great for identifying availability and, in the case of pH, accessibility of nutrients (it should still be performed regularly every 3-5 years), but it does not tell you what is in the actual vine. That’s where petiole tissue testing enters. Long-term nutrient management is best when the two are used together to develop an annual fertilization management plan.
As a reminder, veraison is the preferred time to sample and test for vine nutrient status (regardless of symptoms) due to the relative stability of nutrient concentrations. For details on how to sample, recommended values and testing facilities, please see the following resources:
- OSU factsheet on Grapevine Nutrient Management: https://ohioline.osu.edu/factsheet/hyg-1438
- Taking foliar samples in vineyards and orchards (UMN Extension): https://www.youtube.com/watch?v=eyPs1rTFoNc&t=2s
Fixing nutrient deficiencies now. Is it too late?
Veraison is about the last point of the growing season that fertilization should be done to avoid delaying or harming vine acclimation in the fall. For acute deficiencies, foliar fertilization with soluble formulations is ideal for quickest uptake. Additionally, late-season foliar applications of urea (46-0-0), especially under drought conditions, may increase yeast assimilable nitrogen (YAN) in fruit at harvest. Stuck/sluggish fermentations and hydrogen sulfide by-products that generate “rotten egg” aromas can often be attributed to low YAN. However, baseline YAN values for a given cultivar and site should be understood before using foliar urea as a means of adjusting YAN values in fruit.
Foliar applications are temporary band-aids and do not adequately address chronic deficiencies. It is best to avoid deficiencies altogether through routine monitoring of soil and vine nutrition and annual soil fertility maintenance.
The list below addresses commonly observed deficiencies and remediations via foliar fertilizing. These recommendations are only intended as a short-term solution to situations where deficiencies have been clearly identified through tissue testing and/or visual symptoms. In general, a healthy vineyard with routine soil fertility maintenance does not benefit from additional foliar fertilization, and its use may create unnecessary management costs. We additionally suggest avoiding the use of commercial mixed-nutrient products for foliar fertilizer, as they may either provide insufficient quantities of a target nutrient or unnecessary additions of others. When applying any fertilizer, applicators must be careful in calculating rates to avoid excess fertilization and, with foliar application, burning vines. Tank mixing foliar fertilizers and pesticides may cause phytotoxicity. Consult all labels and/or spot-test before applying to all vines.
- No. applications: 3x
- Rate: 5 lbs urea (2.3 lbs N) per 100 gallons water, applied at 200 gallons per acre
- No. applications: 1x
- Rate: 6-10 lbs potassium sulfate (0-0-53) or chloride (0-0-63) per 100 gallons water, apply at 200 gallons per acre
*Note: excess K additions can result in Mg deficiencies and lead to high pH in fruit.
Phosphorous (P): Foliar application is not recommended
- No. applications: 2x, 1 then again after 2 weeks (bloom time preferred for first application)
- Rate: 16 lbs Epsom salts per 100 gallons water, applied at 200 gallons per acre
- No. applications: 2x (pre-bloom to bloom time preferred for application)
- Rate: 1-2 lbs Solubor (20% B) per acre
By Diane Kinney and Imed Dami, HCS-OSU
Our on-site restrictions remain in place due to the COVID-19 pandemic. We have resumed limited field and greenhouse work upon approval from the Dean of our college but common practices continue to have some delays.
In Wooster, we are just beginning to see veraison in our early ripening varieties (Marquette, La Crescent, and some table grapes). For the most part, clusters have marble-sized berries and we are seeing the beginning of berry touch. We are about 1 week behind 2019 at this time.
Photo: Frontenac blanc in mid-July 2020
July has been a very hot and dry month. We are more than 2 inches behind in rainfall for the month, which is still 1.5” above the long-term cumulative rainfall average. This is greatly different than the past several years. Fortunately, the grapes seem to be doing well with the 1.38” we have recorded and are very clean.
As of the 28th, we have tracked 8 days over 90 oF. Even so, our average daily temperatures are only slightly higher than normal at 75.5 oF. Even with the high temperatures during the day, we are nearly 100 GDD behind the long term with 1705 GDD.
The dry weather has provided us with more opportunities to continue working in the vineyard. We have been able to stay on schedule with leaf removal, crop estimation and cluster thinning. Training of newer vines has progressed well. Timely sprays protected us against severe damage from Japanese beetles earlier in the month. We expect to move forward with vine hedging next week and netting to follow up soon after as veraison progresses. We will begin berry sampling in mid-August to monitor fruit maturity for harvest determination.
Research Assistant Lorena Brown conducting cluster thinning after assessing crop estimation.
Beginning July 2020, the Ohio Grape Electronic Newsletter (OGEN) will be transitioning from the traditional PDF format into single articles published through the OGEN blog. This transition will advance our communication capabilities with you! Below is a brief introduction to why and how the OGEN is changing.
- Faster publishing of new content to better coincide with the timing of events in the vineyard and winery
- Features “tags” and "categories" that provide quick searches for topic-specific articles
- Easy to share individual articles via email and social media
How new content will be distributed:
All content will be posted on the Buckeye Appellation website (https://go.osu.edu/grapes). A monthly e-newsletter containing links to each month's published content, including blog posts, upcoming events, news articles, and The Grape Exchange, will be sent out through the OGEN email listserv. If you would like to have your email added to the listserv, please contact Maria Smith at email@example.com.
Will the past issues of OGEN remain available?
Yes, past issues of the OGEN will remain available for download and review under the “Blog” tab labeled "Newsletter/TGE".