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By: Maria Smith, HCS-OSU

You’re not being misled. We actually are already past the halfway point of the growing season, with many early ripening cultivars entering veraison across the state at least 1-2 weeks ahead of when we typically expect. So, what’s happening?!

Recall, we had very above average early spring temperatures this year. Bud swell to bud break was observed between April 7-April 16 in Wooster this year (Fig. 2). For reference, the 6-year average (2007-2012) date of bud break for many of our earliest Vitis hybrid cultivars is April 17-April 29 (Kinney & Dami, unpublished).


Fig. 1. Vitis hybrid, Block D Unit 2 Wooster, OH 16-Apr-2024 (Top). V. vinifera ‘Chardonnay’, Block B (apical buds), Unit 2, 16-Apr-2024 (Bottom). Photo credit: Maria Smith

Fortunately in Wooster, we skirted major freeze damage during the week of April 22. It is important to note that vines in Unit 2 were delayed/double pruned this spring, and shoots were approximately E-L phenological stages 3-7 during the freeze event, with variation among cultivars. Although our low temperatures reached approximately 30F, the research vineyard only sustained about 10% primary shoot injury. In other regions of the state, particularly the northcentral and central portions of Ohio, there was more significant injury, but unlike 2023, it was contained mostly to early bud break cultivars.

Temperature and GDD

Despite a brief cold snap, temperatures have thus far remained above average from April through June (Fig. 2). To date, Ohio sits between 1600 and 2000 GDD ( This is approximately 150 to 250 GDD ahead of the 30-year average (Fig. 3).

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Fig. 2. Temperature departures from 30-year mean for April, May, and June 2024. Figures from  

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Fig. 3. MGDD (base 50F) departure from 30-year average from 1-April to 15-July 2024. Figure from


Cumulative rainfall this growing season has largely been below average overall (Fig. 4). However, spring months (April and May) saw average to above average rainfall, while cumulative rainfall in June and July has overall been below average (, with exception to NE and NW Ohio.

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Fig. 4. Accumulated precipitation from 17-April to 15-July 2024. Figure from

Vineyard cultural management

Week-over-week, shoot growth has felt on warp speed (Fig. 5). The rate of canopy growth has made keeping up with timely management practices (shoot thinning, positioning, leaf removal, cluster thinning, etc.) a serious challenge this year. As of Monday, we are also starting to see color change (veraison) begin in several cultivars at Hort Unit 2, including early cold-hardy hybrid cultivars and V. vinifera hybrid ‘Regent’ (Fig. 6). It’s strange to say, but we will need to have bird and mammal protection up and sampling for veraison nutrient analysis within the next couple of weeks.

Fig. 5. Phenology of V. vinfera ‘Cabernet franc’ cl 214 (FPS 11) from 16-April to 15-July 2024. Wooster Unit 2. Photo credit: Maria Smith.

Fig. 6. V. vinifera hybrid ‘Regent’ entering veraison 15-July 2024.

Notable vineyard issues

  1. Herbicide drift - Every year, there are reports of herbicide drift injury, most commonly from 2,4-D. This year, however, I have received 15 reported incidences of herbicide injury from 2,4-D, glyphosate, and pre-emergent herbicides in May and June. We were also the unforunatel recipient of herbicide drift injury at Hort Unit 2 in Wooster this May (Fig. 7). Some cultivars were more affected than others, and while most vines have been able to continue growth through damage, we are still seeing abnormal shoot tip growth, hen and chicken berry development (lower fruit set), and distorted cluster development as a result (Fig. 7).

There are steps you can take to document and react to herbicide damage. We also suggest considering filing a complaint with ODA as soon as a drift injury event is suspected.

Fig. 7. Vitis hybrid Crimson Pearl following 2,4-D injury at Hort Unit 2, 14-May 2024 (top) and 15-July 2024 (middle). Other cultivars, such as Vitis hybrid MN 1256 have more variable fruit set from 2,4-D injury (bottom), 15-July 2024.  

  1. Disease – With how fast this season has progressed, it’s been a tough to stay on task for both canopy management and spray schedules. Thus far, Phomopsis has been the leading disease issue, although some black rot, powdery, and downy mildew have been observed in recent weeks as summer temperatures, high humidity, and thunderstorms have taken hold. Because Phomopsis infections prior to fruit set do not show up in berries until closer to harvest, we will have to wait and see what level of fruit infection occurred this spring. ***This is your annual reminder that disease management programs are preventative, implemented timely, use effective chemistries and application rates, appropriately rotate FRAC codes, and are integrated with good canopy management. There are several resources available to assist with understanding disease lifecycles, control, and building your spray program:
  2. Insects – So far, no news is good news when it comes to Spotted Lanternfly in vineyards. However, we should note that they currently have a population foothold in 11+ Ohio counties.  We continue to stress reporting sightings of SLF to the Ohio Plant Pest Reporter (and squash them). Right now, adults are beginning to emerge in warmer regions of the state, but in Cleveland, they are still in stage 3 and 4 nymphs (Fig. 8).  Continue taking caution to not transport them around via yourself or your car!

Other insects have been of minor concern: Out scouting, there have been signs and symptoms of flea beetles, leafminers, foliar Phylloxera, grape berry moth, and Japanese beetles. Ensure that you are scouting, monitoring, and using GDD to appropriately time your insecticide applications for control. The Midwest Fruit Pest Management Guide contains content on insect chemical control options in addition to fungicides.  

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Fig. 8. Spotted Lanternfly stage 3 and 4 nymphs in downtown Cleveland, 13-July 2024. Photo Credit: Fred Michel.

Fig. 9. Grape berry moth discoloration in V. vinifera ‘Chardonnay’, Unit 2 Wooster. Photo Credit: Diane Kinney

Posted In: Viticulture
Tags: vineyard updates, 2024 season
Comments: 0

By: Erdal Ozkan, Professor, Extension Pesticide Application Technology Specialist, FABE-OSU

For many reasons, including production costs, safety, and the environment, it is important to maximize pesticide deposits on the target when spraying. Spray drift is a major challenge to pesticide applicators trying to achieve this goal. Although complete elimination of spray drift is impossible, it can be significantly reduced by awareness of its major causative factors, and by taking precautions to minimize their influence on the off-target movement of droplets. Extensive information related to factors influencing spray drift is in the Ohio State University Extension publication (FABE-525) “Effect of Major Variables on Drift Distances of Spray Droplets”.

The risk of drift is considerably higher when spraying in orchards and vineyards compared to spraying in field crops for three main reasons:

  1. The target being sprayed in field crops is relatively uniform, it’s a short distance from the nozzles, and the droplets are directed downward. The target in orchards and vineyards is not uniform in size and shape (there may be gaps in canopy), there is a much longer distance from the nozzles, and the droplets are directed in an upward trajectory.
  2. The type of sprayer used in field crops releases the droplets downward just over the target. The sprayer used in orchards and vineyards uses a powerful fan that blows droplets in a horizontal and upward trajectory, making the droplets much more susceptible to drift.
  3. The type of nozzle and droplet size used in field crop spraying is most often a flat-fan nozzle that discharges relatively large droplets. Orchard and vineyard sprayers are generally equipped with hollow-cone nozzles that produce very fine to fine category droplets.

Therefore, more precautions should be taken to reduce the drift risk when spraying in orchards and vineyards.

Strategies to Reduce Spray drift

Some factors that affect drift, such as weather conditions, are out of the control of the pesticide applicators spraying in orchards and vineyards. However, many of the factors affecting drift are under the control of the applicators. Here are some of the key cost-effective and practical strategies to reduce spray drift:

  • Keep drift in mind when selecting your sprayer. Although the air-assisted (airblast) sprayer type shown in Figure 1 (with radial spray discharge) is used by most fruit growers in the U.S., many other less drift-producing types of air-assisted sprayers, such as the one shown in Figure 2 (with horizontal spray discharge) are used in other parts of the world. Sprayers producing horizontal air and spray flow generally produce less spray drift. Take a look OSU Extension publication (FABE-533) “Sprayers for Effective Pesticide Application in Orchards and Vineyards”, which provides a discussion of all major types of sprayers used in orchards and vineyards.

  • Consider switching to low-drift nozzles. In the U.S., the typical sprayer used in orchards and vineyards is an airblast sprayer equipped with hollow-cone (most often) or conventional flat- fan nozzles (less common). Both nozzle types produce extremely fine, very fine, and fine droplets, which are highly susceptible to drift. Hollow-cone nozzles operated at high pressure are especially susceptible. In recent years, nozzle manufacturers have introduced new nozzles that significantly reduce the number of extremely small, drift-prone droplets. In other parts of the world— especially Europe— most growers are gradually switching to these low-drift air-induction nozzles to spray fruit trees.
  • Spray pressure affects the size of droplets released from a nozzle. Higher pressure produces smaller droplets. Therefore, avoid operating the sprayer at high pressures. Although 200 to 300 psi is the norm for manU.S. growers when operating airblast sprayers, a pressure of 100 to 150 psi is more than adequate to generate the fine to medium size droplets that improve penetration and coverage on the target.
  • Spraying in high winds, high temperatures, and low relative humidity increases the risk of spray drift. If weather conditions are not favorable, and there is a concern about spraying that might result in drift, wait for more favorable conditions. Review the forecast and schedule spraying accordingly. Use apps that provide current, local weather conditions and use that information to make sound decisions on when to spray. Be aware that wind speeds shown in apps display data taken from nearby weather stations that may not reflect the wind speeds in your specific spraying location. Therefore, it is best to carry a small hand-held, battery-powered wind meter (anemometer) to check the wind speed several times before and during spraying. The price of a wind meter is usually less than one-third the hourly fee a lawyer can charge a client sued for drift-related damages.
  • Adjust the sprayer fan air-flow rate and volume so that the air being directed into the canopy replaces the air already in the canopy but dies down significantly as it reaches the other side of the canopy. A proper air adjustment results in very little spray droplets escaping the canopy. As a side benefit, reduced air assistance results in lower fuel consumption.
  • The travel speed of the sprayer also influences spray drift. Even when adjustments are made to restrict air intake into the fan, too much air may reach the canopy if the travel speed is extremely low. Slow travel speeds allow the canopy to be exposed to the air flow for a much longer time, thus contributing to drift.
  • When spraying the outer side of the last row, turn off the nozzles on the side of the sprayer that are pointed away from the canopy. In addition, if you are using a conventional airblast sprayer with radial air discharge, cover the air exit port on the side of the sprayer facing away from the canopy. Both actions further reduce the risk of spray drift.
  • Carefully direct the air from the fan towards the canopy to ensure that the sprayed droplets are intercepted by the canopy. With conventional, radial discharge airblast sprayers, deflector plates must be installed on both the top and the bottom of the fan, and on both side of the sprayer, to guide the spray plume toward the canopy and at a level equal to the canopy's height. The size of the deflectors should be big enough to effectively direct the air at the canopy.

A successful spray operation in orchards and vineyards achieves maximum efficacy from the pesticide applied while minimizing the off-target (drift) movement of pesticides. Spray drift poses health risk to nearby people and animals, increases the risk of polluting natural resources like air and water, and wastes pesticides that could have been used to treat pests in orchards and vineyards. A brief discussion on practical ways to reduce spray drift is discussed in this article. More comprehensive information on this topic is given in the Ohio State University Extension publication (FABE-535) “Strategies to Minimize Spray Drift for Effective Spraying in Orchards and Vineyards”.


By: Maria Smith, HCS-OSU

The results from the 2023 Ohio Grape Pricing and Production Index are in and summarized below!

  • 56 total respondents
  • Vineyard sizes ranged from 1-5 to >50 acres
  • 52 different cultivars reported:
    • 38 cultivars with reported yield
    • 26 cultivars with reported price
    • 9 cultivars with reported juice and/or bulk wine prices
  • Average price per cultivar grouping:
    • Native: $936 per ton
    • Hybrid: $1522.50 per ton
    • Vinifera: $2226.51 per ton

Visit this link for a PDF copy of the full report and a breakdown of acreage, yield, and price by cultivar. Survey results dating back to the 2018 growing season can be found on our website here.

Posted In: Viticulture
Tags: Grape Pricing, 2023 season, Viticulture
Comments: 0

By: Maria Smith, HCS-OSU

Buds are breaking across Ohio and here in Wooster (Fig. 1), but frost risk looms again tonight. A few regions of Ohio reached damaging temperatures for green tissues on the morning of April 22 (Fig. 2), with minor damage observed in some vineyards in Central and Southern Ohio.

Figure 1. Bud status of V. vinifera ‘Cabernet franc’ (top) and Vitis hybrid NY03.06 (bottom) on Monday, April 24. Wooster, Hort Unit 2 minimum temperature for 4/22 was 34.5F (data from Tissue phenology ranges between stages E-L 3-7 throughout both Vinifera and hybrid variety trial blocks. Photo credit: Maria Smith


Figure 2. Minimum low temperatures for Monday, April 22, 2024. Figure from

However, we are expecting another evening of wide-spread frost potential this evening for Central and Northern Ohio. This blog post is a reminder to visit our resources on spring frost: preparing for spring frosts and managing injury or obtaining a copy of the spring frost bulletin from OSU Extension.

The following is a message from State Climatologist Aaron Wilson about the next predicted frost for this evening.

It looks like we do have one more night tonight to get through this season. Freeze Watches are in place for central and northern Ohio. Skies will clear and winds will relax tonight with widespread frost likely. Lows will fall into the upper 20s to low 30s across northern Ohio (except near Lake Erie which is warm enough to keep temperatures a bit warmer). Traditional cold spots may settle even colder. The timing will likely be about 4-5 hours of sub-freezing temperatures, between 2 and 7am.

Here are the current counties included in the Freeze Watch, but frost across southern Ohio even with official temperatures in the mid to upper 30s is not out of the question tonight.

After tonight, the forecast is promising in terms of freeze potential. Currently, there does not appear to be a threat through the first week of May, which is a good sign that we may be close to the end of our worry!

Our strategy at Hort Unit 2 to prepare for spring freeze in 2024

Delayed (waiting as long as possible) or double (pre-pruning to long spurs) pruning is one of the most reliable strategies for delaying the onset of bud break, thus helping us avoid frost events. Delayed/double pruning works by taking advantage of the strong apical dominance of grapes, whereby the buds on the top of canes open first and the buds on the bottom of the cane that would be retained for fruit production remain closed on the bottom (Fig. 3). This tactic can aid in delaying bud break by up to two weeks. It should be noted that final pruning should be completed by the time the top buds are approximately 1-2” in length to avoid potential impacts on yield from basal buds/blind nodes or excessive delays in fruit ripening. Additionally, delayed/double pruning is best performed in spur-pruned systems.

This year, we have elected to delay pruning, a feasible tactic at Hort Unit 2 given the size of the research vineyard. This method can be a successful strategy in small (< 5-acre) vineyards or for those varieties, such as Marquette, La Crescent, Itasca, etc., that exhibit very early bud break.

Figure 3. Delayed pruning of V. vinifera ‘Chardonnay’ on 4/22. Vines were pruned on 4/23. Note: Apical buds are approximately 1” at E-L stage 5 (middle photo), while basal buds are less developed at E-L stage 3 (bottom photo). All 3 photos were taken of the same vine. Photo credit: Maria Smith

Posted In: Viticulture
Tags: 2024 season, Spring Frost
Comments: 0

By: Maria Smith and Imed Dami, HCS-OSU

It is no surprise to anyone who has been out in the vineyard pruning that hydraulic pressurization and sap flow (“bleeding”) from pruning wounds has been seen earlier than normal due to the above average temperatures over March (Fig 1, photo).

We monitor the warmth of the growing season by recording the growing degree days (GDD). Last Friday (22 March 2024) the GDD at Wooster, Unit 2 was 43, which is higher than the historical average and is about two weeks ahead. However, when we checked the stage of development of the earliest bud breaking varieties, the majority of buds were still at the closed stage with some at the wool stage (see photos). The cool/cold weather we have experienced in the past few days has helped slow bud growth, which is a good thing. Although the recent weather event had no negative impact on bud survival, we are still concerned by the potential for early budbreak this season.  

As an annual reminder, we are freeze prone (< 32F) from roughly April through mid-May, with the latest observed freezes occurring through early-May to early-June, depending on region (Fig 2).

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Figure 1. Temperature departures from the 30-year average for March 1-March 24, 2024. Temperatures have ranged between 5 to 11F above average across Ohio during this period.

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Vine “bleeding” from pruning wound. March 13, 2024, Unit 2 Wooster. Photo from Diane Kinney

Date of Median Last 32°F Freeze

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Figure 2. Median date of last 32F freeze (top) and latest date of observed 32F freeze (bottom). Figures from

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Cabernet franc grapevines grown at the research vineyard in Wooster. Photo taken by Imed Dami on 22 March 2024. 

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Brianna grapevines grown at the research vineyard in Wooster. Photo taken by Imed Dami on 22 March 2024. 

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Itasca grapevines grown at the research vineyard in Wooster. Photo taken by Imed Dami on 22 March 2024. 

Current susceptibility to freeze injury

Several growers reached out this week with concerns about potential bud injury due to temperatures reaching near 20F (Fig 3).

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Figure 3. Minimum low temperatures on 3/21/24. Most regions hit lows in the low-20s, with some areas in the 10s.

Across the Eastern US, buds are undergoing “cold deacclimation”, which is the transition from maximum winter cold hardiness to a cold-sensitive state. With the recent cold temperatures last week, there have been concerns that these temperatures may cause damage, even though buds are still dormant.

The cold hardiness, or LT50 (lethal temperature that kills 50% of primary buds), of the cold sensitive vinifera, Sauvignon blanc, was -1.8F on 12 March 2024. Its cold hardiness was -9.9F on 11 January 2024.  In the past 10 days, the minimum air temperature at Wooster, Unit 2 was 17.8F (on March 21).

A bud cold hardiness model released by Dr. Jason Londo’s lab at Cornell, seeks to provide broader guidance throughout the Eastern US on real-time estimates for bud cold hardiness. This model provides estimated cold hardiness for several key regional wine and juice grape cultivars. Combined with our own bud DTA cold hardiness measurements in Wooster, we are highly confident that buds should not have experienced injury from this past week’s cold temperatures. However, if you remain concerned, it is advised to select a few buds to dissect to verify if any injury occurred at your site.

Planning for another year of spring frost risk and damage

Given that vineyards will be at risk for dormant and/or green tissue injury for several weeks to come, it is important to be prepared for mitigating and responding to injury. We have experienced some level of spring frost in Ohio for the past five years in a row! Be prepared by reading up on some of our previous posts on preparing for spring frosts and managing injury or obtaining a copy of the spring frost bulletin from OSU Extension.

We will be keeping you updated over the next couple of months for the emergence of bud break and any major spring frost events. Although we may not personally enjoy these cold spells, it is helpful for pushing back bud break and our spring frost risks. 

Posted In: Viticulture
Tags: Viticulture, Winter Injury, 2024 season
Comments: 0

By: Maria Smith, HCS-OSU

It’s still winter, but thanks to this El Niño year, it sure hasn’t felt like it in Ohio. Daily average temperatures over the past 30 days have ranged between 6-10 °F above the 30-year mean (Fig. 1). Many of our vineyards are likely taking advantage of this weather to prune the vines for the upcoming year. To those with smaller vineyards (< 10 acres), there is still plenty of time to get your pruning done through March and early April before buds begin to break dormancy. For a year with this mild of a late-winter, delaying your dormant pruning as long as possible can be considered advantageous to staving off bud break among your preferred yield-producing buds.  

The goal of this post is to remind you and your crew about pruning best practices following last week’s Wooster grapevine pruning workshop. In 2023, we published a pruning primer article about the what, when, and whys of pruning. In this companion article, we’ll touch on vineyard sanitation and a few routine pruning errors so that you can maximize the long-term health and productivity of your vines.

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Fig 1. 30-day Average temperature departure from mean Feb 9, 2024 – March 9, 2024. Photo from

Vineyard Sanitation:

Did you have grape diseases in the vineyard during 2023? Fungal diseases such as Anthracnose, Phomopsis, and black rot are well-known to overwinter on woody tissues (canes, cordons, trunks) and persistent mummified fruit that was left in the vineyard overwinter (Fig. 2). These infected tissues go on to serve as a source of pathogen propagules for infecting new, healthy tissue over the next growing cycle. Similarly, crown gall bacteria (Agrobacterium vitis, Fig. 3) can persist for years in infected tissues and is managed through renewal of vine parts during pruning.

Vineyard sanitation, or the act of removing and destroying dormant, infected tissues while pruning can aid in the reduction of pathogen populations available to infect in subsequent seasons. If disease was a significant issue in your vineyard, it is best practice to destroy tissue by burning, burying, or removing completely from the vineyard rather than composting, since inadequate temperatures during composting can fail to kill propagules. Sanitation should also extend to tools through regular cleaning and sharpening (sharp-cut pruning wounds heal quicker) of pruning tools.

Fig 2. Phomopsis lesions (left) will persist on shoots that lignify and become canes; black rot mummy berries (right)

Fig. 3 Grape trunk infected with crown gall, a bacterium that causes tumor-like growths (galls) on infected woody tissues (trunks, cordons, roots).

HOWEVER, if your vineyard was clean of disease, cuttings may be mulched using a flail mower or brush hog (Fig. 4) directly in the row. Avoid using a regular lawn mower deck to chop up pruned wood, especially larger pieces of trunks or cordons. 

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Fig. 4 Flails on a rotating drum. Flail mowers and brush hogs can chop up small diameter woody materials. Photo from:

Routine pruning and training issues:

Grape pruning and training are not intuitive, and even experienced practitioners make mistakes in the process. Here are a few of the most common issues that I encounter when out assessing vineyards in the late-winter:

  • Training weak wood: healthy wood is 1) ¼ to ½” in diameter, 2) sun exposed in the previous year, 3) has dark brown periderm (outer bark). Canes that are small and weak or large and vegetative are less cold hardy and less productive than optimal wood quality.
  • Retaining excessive bud numbers after final pruning: Pruning should remove approximately 80-90% of the vine growth from the previous season. Retaining too many buds after final pruning sets the vine up to produce shoots with smaller clusters and less shoot growth than vines with an “optimal” number of buds. Refer to the Midwest Grape Production Guide for guidance on balanced pruning practices.
  • Training cordons that are too long: Cordons are best established in segments of 12 to 15” in length, especially in Vinifera cultivars. This is to encourage all buds along the cane to develop into healthy shoots. Leaving excessively long cane segments while training or retraining cordons can result in blank regions where shoots do not develop, thus leading to canopy gaps and a less productive vineyard.
  • Making poor pruning cuts: Wounding on the vine is an entry to pathogen infections. This includes pruning wounds. Avoiding large flush cuts on older (2+ year-old wood), using sharp pruning shears, and pruning in dry conditions are important to reducing risks for spur/cordon/trunk infections and dieback.
  • Consider the spur, cane, and bud position: We want to select canes, buds, and spurs that help us best conform to and maintain our training system. When training young vines, bud positioning should be considered when making cuts to ensure that shoots and subsequent canes are positioned along our fruiting wires without strong bends or breaks at the base that can restrict sap flow through the vascular tissues. Selecting shoots/canes along the trunk that can be easily arched upwards from under the fruiting wire or those that conform to the fruiting wire when extending/replacing cordons are preferred to shoots/canes that emerge from buds positioned above the fruiting wire. 
Posted In: Disease mangement, Viticulture
Tags: Viticulture, pruning
Comments: 0

By: Melanie L. Lewis Ivey, Associate Professor, Extension Fruit Pathologist, Department of Plant Pathology

This article can be found in the January 2024 issue of Ohio Fruit News.

In December 2023, the Environmental Protection Agency (EPA) proposed an interim decision for the registrations for thiram, ferbam and ziram. Despite updates and recommendations for ziram, presented during the public comment period for the 2021 proposed interim decision, changes were not made to the previous risk picture and proposal.

Thiram, ferbam and ziram are critical to the successful management of fruit diseases and the prevention of fungicide resistance development. Final decisions on the proposed interim decisions are scheduled for April-June 2024. An open 60-day public comment period is planned for the beginning of 2024. Once the comment period opens, comments can be submitted on-line or by mail. Open comment periods are announced at

Representatives from the EPA have emphasized that without new data or significant numbers of comments, the proposed interim decision on these products is unlikely to change.

The EPA will only announce final changes to the registrations of all pesticides through the “Bulletins Live – 2” website. However, the OSU Extension Specialty Crop Team will make every effort to keep fruit producers in the state updated.

Figure 1. Peach leaf curl is most effectively controlled using Ferbam or Ziram. Image courtesy of K. Peter, Penn State University.

Docket EPA-HQ-OPP-2015-0433

Risks of Concern: There are risks of concern for “fish (both freshwater and estuarine/marine), aquatic invertebrates, mammals, terrestrial invertebrates, birds, and aquatic and terrestrial plants.” In addition, there are “exposure concerns to occupational handlers and post application risks”.

Proposed Mitigation: To address the risks of concerns for thiram the following mitigation strategies were proposed.

  • Cancellation of all non-seed treatment uses such as strawberries, peaches, non-bearing trees, shrubs, nursery stock, ornamentals.

  • Cancellation  for  all  commercial  seed treatment uses.

  • Only on-farm seed treatment for liquid formulations and use of a PF10 respirator for some crops (snap bean, rice, soybean, and wheat).

  • Limit animal repellency use in nursery settings (ornamentals, vegetables, trees, container stock) to 84178-1 only. This product is also registered for other use sites and those uses must be removed from the label. Applications must be made with a manually pressurized handgun. All other products must remove their animal repellency use from the label.


Risks of Concern: There are risks of concern for “fish (both freshwater and estuarine/marine), aquatic invertebrates, mammals, terrestrial invertebrates, and birds.” In addition, there are “exposure concerns to occupational handlers and occupational post application risks for workers”.

Proposed Mitigation: To address the risks of concerns for ferbam the following mitigation strategies were proposed.

  • Cancellation of all uses on apple, pear, citrus, mango, and cranberries.

  • Restrict the application method to only be applied by a mechanically pressurized handgun on peach and nectarine for dry flowable formulations and require the use of a PF50 respirator.

  • Only dormant period applications for peaches and nectarines.


Risks of Concern: There are risks of concern for “fish (both freshwater and estuarine/marine), aquatic invertebrates, mammals, birds, and terrestrial invertebrates”. In addition, there are “dermal and inhalation exposures to occupational handlers, post-application occupational risks (dermal), and bystander (non-occupational) risks to adults (dermal) and children (combined dermal and incidental oral)”.

Proposed Mitigation: To address the risks of concerns for ziram the following mitigation strategies were proposed.

  • Cancellation of all uses on all crops.

  • Cancellation of uses for paint preservatives.

  • Engineering controls for the non-paint materials preservative uses.

  • Reducing the maximum application rate in all ziram-preserved building materials.

  • Limiting application to the dry-end of the paper preservation process.

Posted In: Disease mangement
Comments: 0

By Imed Dami and Diane Kinney, HCS-OSU

This article summarizes the 2023 dormant and growing seasons and the impact of weather on grape varieties grown on the research vineyard at the OSU-OARDC in Wooster, Ohio.

Weather: Temperature

Our 2023 growing season was greatly affected by a freeze event on December 23, 2022 to -7 F. Bud injury was higher than normal due to warmer (3F) than a typical December. The early part of the year was significantly warmer than both the long-term average and 2022 temps. This did not hold true for the early growing season though as temperatures were below in both areas. In Wooster, we missed a frost event in mid-May that greatly affected other grape growing regions in the state. Our last date for temperatures below freezing in the spring was April 27th which coincided with bud break. Phenological progress was slow due to cool, dry temperatures. During fruit ripening in early fall, temperatures followed closely to both long-term and 2022. Cumulatively, as year end, we are only slightly above 2022. We did have an earlier fall frost date of October 31st resulting in a lower-than-average FFD of just 187 in comparison to 201 in 2022.

Weather: GDD

Nearly 40 GDD units were gained during early winter from the 1st of January through 1st of April. April continued to be slightly above both 2022 and the long-term averages but things drastically dropped off for the entire growing season May through September. By years’ end, we are at only 2734 GDD vs 3104 in 2022 which was already significantly lower than 2021. In relation to the long-term 30-year average of 3058 GDD, we are 324 GDD lower at this time. This is the first time that yearly GDD dropped below 3000 in 10 years.

Weather: Precipitation

Annual precipitation was above the long-term average but significantly below 2022 (34.53” vs 41.03”). That being said, we did have near drought like conditions during the early growing season mid-May through mid-June with nearly no rainfall at all. This early drought ended with nearly 3” the last two weeks of June alone. July and September were also very dry. A 5-day period in early August recorded 2.69” with another near 3” the last week of the month. In September, we only recorded 0.32” with November at 1.36”. In general, and except August, we had a drier than normal summer-fall, which impacted disease pressure in 2023.

Vineyard Notes:

2023 Winter freeze injury:  The deep freeze of December 23, 2023 caused significant bud injury. Vinifera varieties (15) sustained 85-100% primary bud injury; Table grapes (8): 55-100%; hybrids (19): 15-82%. The causal claims, that the temperature dropped very fast, are not accurate. In our vineyard, temperature dropped about 50F in 24 hrs or 2F/hr. That is considered a normal “freezing rate”. It is the mild December that led to “deacclimation” of vines. Also, the freeze-thaw cycle (45F/-7F) just before the event exacerbated the extent of damage. However, the crop loss in some varieties was not as severe as expected due to our pruning adjustment. For example, Chardonnay sustained 85% bud injury but produced 3 tons/acre after hedge (or minimal) pruning.

Diseases and insects: With the drier weather, diseases were also less of a problem this year. Bird and racoon damage was nearly non-existent, but yellow jacket damage was fair which led to high sour rot incidence. Dr. Ivey confirmed a new disease, called ripe rot, for the first time in Ohio that we found in some of the varieties in Wooster. More information regarding this will be shared at a later time.

Fruit quality:  Sour rot continues to be our biggest challenge in fruit quality. Harvest began on August 23rd for Briana and our final harvest occurred on October 5th for Cabernet franc. Despite a very low GDD, we were able to ripen fruit of most varieties and fruit composition was appropriate. For example, in 2023, sugars in 14 varieties averaged 19.9 Brix. In 2022, the average was almost the same at 19.8 Brix. Acidity was also below 10g/L in general despite a cool season. TA averaged 7.5 g/L in 2023 and 7.9 g/L in 2022. It is possible that fruit chemistry was not impacted negatively (based on low GDD), because we had a low crop load due to winter injury. So there was less fruit to ripen in most varieties. We also like to think that our group did a good job with canopy management that enhanced fruit quality even in a cool year!

Table: 2023 Harvest fruit composition of selected grape varieties at the Wooster research vineyard: (2022 data)



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Tags: 2023 season, Vineyard Update
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***This factsheet can be found on Ohioline at or as a printable PDF online via the OSU Buckeye Appellation or Fruit Pathology websites.***

By: Melanie L. Lewis Ivey, Associate Professor, Department of Plant Pathology, OSU CFAES-Wooster Campus

Ripe Rot of Grape

Ripe rot is a late-season disease that primarily occurs in warm, moist, growing regions in the southeastern United States. However, outbreaks in Ohio and other states in the Midwest and Northeast occur when conditions are warm and wet during fruit maturation. The disease is caused by multiple species of the fungus Colletotrichum. Ripe rot reduces fruit yield and adversely affects the chemical composition and quality of grapes and wine, leading to undesirable flavors and color.

Disease Development and Symptoms
Ripe rot is caused by multiple species of the fungus Colletotrichum. In the spring, warm (77–86 degrees Fahrenheit /25–30 degrees Celsius) rains initiate the production and release of spores from tissues infected the previous season. Berries are susceptible to infections from bloom through harvest, but symptoms first appear just after veraison (the onset of ripening) and close-to-fruit maturity. Symptoms on berries of white-fruited cultivars first appear as reddish-brown circular lesions (Figure 1A) that can be mistaken for sunburn or chemical injury. The lesions expand in concentric circles until they cover the entire berry. As the berries rot, they become covered with black spots (fungal fruiting bodies or acervuli). During wet weather, the berries become covered with salmon-colored spore (conidia) masses (Figure 1B and 1C). Symptoms on red-fruited berries can be difficult to discern without the presence of spores and can be confused with sour rot (see PLPATH-FRU-50 Sour Rot Disorder of Grape). Rain spreads spores to other berries and clusters. The berries eventually shrivel into hard raisin-like structures called mummies, which usually remain attached to the berry cluster. Disease symptoms on the leaves, shoots, peduncles (cluster stems), or pedicels (berry stems) are not common. The fungus primarily overwinters on mummified berries and infected pedicels or peduncles, but also overwinters in woody tissues and dormant buds.

Figure 1. Ripe rot of white-fruited grape. Reddish- brown circular lesions on berries are the first symptoms of ripe rot (A). Berries covered in fruiting bodies of the ripe rot fungus (B). Salmon colored spores on the surface of a berry (C).


Cultivar Selection

All cultivated grape (North American, V. vinifera, and interspecific hybrids of V. vinifera) varieties are susceptible to infection by the ripe rot fungus. However, some varieties appear to be more susceptible than others (Table 1). Susceptibility can vary from season to season.

Table 1. List of ripe rot susceptibility of common varieties grown in the Midwest and Northeastern United States1.

Resistant Chardonel, Concord, Delaware, Ontario, Syrah
Susceptible Chambourcin, Chardonay, Marquette, Merlot, Niagara, Neptune, Sauvignon blanc, Seyval
Highly Susceptible Cabernet Franc, Cabernet Sauvignon, Carlos, Flame, Muscat, Golden Muscat, Petit Verdot, Vidal Blanc

1Data from Shiraishi et al. 2007

Cultural Practices

Dormant season pruning to remove mummies can reduce the number of spores produced and released in the spring. Pruning debris should be removed from the vineyard before bud break, especially vineyards with a history of ripe rot.

Chemical Control

Fungicides applied early in the season, from bloom to three to four weeks after bloom, are effective at preventing infections and limiting late-season rot. If weather conditions favor disease development close to harvest (i.e., warm, wet, high humidity), additional fungicide applications are recommended. For late-season fungicide applications, always check the pre-harvest interval (PHI) of the fungicide to confirm that it can be used close to harvest.

Commercial growers can consult the Midwest Fruit Pest Management Guide (Bulletin 506) and/or Developing an Effective Fungicide Spray Program for Wine Grapes in Ohio (Plant Pathology Series No. 147) for current fungicide recommendations.

Backyard growers should integrate early-season fungicide application with cultural practices to control ripe rot disease. Ripe rot disease can be confused with other fruit rots, such as sour rot or black rot. Backyard growers are encouraged to contact the C. Wayne Ellett Plant and Pest Diagnostic Clinic ( or 330-263-3721) for disease confirmation before making late-season fungicide applications.

Post-harvest Storage Practices

Grape clusters with ripe rot can negatively affect the quality and color of wine or juice. Fruit infected with ripe rot fungus that have not developed symptoms may develop symptoms during storage. To prevent rotting while in storage, sort out cracked, discolored, and rotting berries; place the berries in a breathable container; and store them at 30–32 F (-1–0 C).

Useful Resources

To learn more, check out Ohio State University Extension resources on ripe rot of grapes and related topics:

Developing an Effective Fungicide Spray Program for Wine Grapes in Ohio from Fruit Pathology Laboratory website from Ohio State University Extension at

Sour Rot Disorder of Grape, (2021) from Ohio State University Extension’s Ohioline, at

Midwest Fruit Pest Management Guide (OSU Bulletin 506) from Purdue Extension Education Store at


Shiraishi, M., Koide, M., Itamura, H., Yamada, M., Mitani, N., Ueno, T., Nakaune, R., and Nakano, M. 2007. Screening for resistance to ripe rot caused by Colletotrichum acutatum in grape germplasm. Vitis 46:196-200

By: Maria Smith, HCS-OSU

The new USDA plant hardiness zone maps have been updated for 2023 and were released this week. These updates occur approximately every 10 years, with the last maps released in 2012. The following press release from the USDA provides explanation for how the new zones are calculated and the 30-year timespan of winter minimum temperatures used to calculate the new zones.

These maps provide general guidance to new and existing grape growers to match vine cold tolerance with site conditions. HOWEVER, it should be noted that these zones are based on averages of winter minimum temperature, and mesoclimate conditions need to be accounted for in cultivar selection. As it is also stated in the press release and instructions for map use, winter extreme temperatures are variable and do dip below zone averages. In my 5 years at OSU, we have seen varying levels of winter injury in Vinifera in 2022, 2021, and 2019. And that does not include the polar vortex years of 2014 and 2015. All that to say, just because most of the state is now considered Zone 6a and 6b, does not necessarily indicate that Vinifera will survive at every site in every year. Choosing to plant Vinifera comes with significant risk of winter injury.

It is still best practice to track weather at your site to understand annual variation in weather conditions, be judicious in your cultivar selection, and plan to protect your grafted vines from winter injury.

You can use the interactive map to find your zone based on Zip code or download high-resolution copies of the map at
A map of ohio with different states

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Figure 1. Ohio’s cold hardiness zones now include 5b (-15 to -10F), 6a (-10 to -5F), 6b (-5 to 0F), and 7a (0 to 5F).

A map of the united states

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Figure 2. Updated national map of USDA cold hardiness zones for 2023


USDA Unveils Updated Plant Hardiness Zone Map

Contact: Jan Suszkiw

WASHINGTON, DC, Nov. 15, 2023—The U.S. Department of Agriculture (USDA) today released a new version of its Plant Hardiness Zone Map (PHZM), updating this valuable tool for gardeners and researchers for the first time since 2012. USDA’s Plant Hardiness Zone Map is the standard by which gardeners and growers can determine which plants are most likely to thrive at a location. The new map—jointly developed by USDA's Agricultural Research Service (ARS) and Oregon State University's (OSU) PRISM Climate Group—is more accurate and contains greater detail than prior versions.

It is available online at In addition to the map updates, the Plant Hardiness Zone Map website was expanded in 2023 to include a “Tips for Growers” section, which provides information about USDA ARS research programs of interest to gardeners and others who grow and breed plants.

The 2023 map is based on 30-year averages of the lowest annual winter temperatures at specific locations, is divided into 10-degree Fahrenheit zones and further divided into 5-degree Fahrenheit half-zones. Like the 2012 map, the 2023 web version offers a Geographic Information System (GIS)-based interactive format and is specifically designed to be user-friendly. Notably, the 2023 map delivers to users several new, significant features and advances. The 2023 map incorporates data from 13,412 weather stations compared to the 7,983 that were used for the 2012 map.

Furthermore, the new map’s rendering for Alaska is now at a much more detailed resolution (down from a 6 ¼ -square-mile area of detail to a ¼ square mile). "These updates reflect our ongoing commitment to ensuring the Plant Hardiness Zone Map remains a premier source of information that gardeners, growers and researchers alike can use, whether they’re located in the continental United States, Alaska, Hawaii or Puerto Rico,” said ARS Administrator Dr. Simon Liu.

Approximately 80 million American gardeners and growers represent the most frequent users of the USDA Plant Hardiness Zone Map. However, they’re not the only ones with a need for this hardiness information. For example, the USDA Risk Management Agency refers to the map’s plant hardiness zone designations to set certain crop insurance standards. Additionally, scientists incorporate the plant hardiness zones as a data layer in many research models, such as those modeling the spread of exotic weeds and insects.

The 2023 Plant Hardiness Zone Map is now available as a premier source of information that gardeners, growers and researchers alike can use.

Plant hardiness zone designations represent what’s known as the “average annual extreme minimum temperature” at a given location during a particular time period (30 years, in this instance). Put another way, the designations do not reflect the coldest it has ever been or ever will be at a specific location, but simply the average lowest winter temperature for the location over a specified time. Low temperature during the winter is a crucial factor in the survival of plants at specific locations.

As with the 2012 map, the new version has 13 zones across the United States and its territories. Each zone is broken into half zones, designated as “A” and “B.” For example, zone 7 is divided into 7a and 7b half zones. When compared to the 2012 map, the 2023 version reveals that about half of the country shifted to the next warmer half zone, and the other half of the country remained in the same half zone. That shift to the next warmer half zone means those areas warmed somewhere in the range of 0-5 degrees Fahrenheit; however, some locations experienced warming in the range of 0-5 degrees Fahrenheit without moving to another half zone.

These national differences in zonal boundaries are mostly a result of incorporating temperature data from a more recent time period. The 2023 map includes data measured at weather stations from 1991 to 2020. Notably, the 2023 map for Alaska is “warmer” than the 2012 version. That’s mainly because the new map uses more data representing the state’s mountain regions where, during winter, warm air overlies cold air that settles into low-elevation valleys, creating warmer temperatures.

The annual extreme minimum temperature represents the coldest night of the year, which can be highly variable from year to year, depending on local weather patterns. Some changes in zonal boundaries are also the result of using increasingly sophisticated mapping methods and the inclusion of data from more weather stations. 

Temperature updates to plant hardiness zones are not necessarily reflective of global climate change because of the highly variable nature of the extreme minimum temperature of the year, as well as the use of increasingly sophisticated mapping methods and the inclusion of data from more weather stations.  Consequently, map developers involved in the project cautioned against attributing temperature updates made to some zones as reliable and accurate indicators of global climate change (which is usually based on trends in overall average temperatures recorded over long time periods).

Although a paper version of the 2023 map will not be available for purchase from the government, anyone may download the new map free of charge and print copies as needed.

The Agricultural Research Service is the U.S. Department of Agriculture's chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in U.S. agricultural research results in $20 of economic impact.

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