Vineyard Updates - July 2024
Wednesday, July 17th, 2024
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(2007-2012) date of bud break for many of our earliest Vitis hybrid cultivars is April 17-April 29 (Kinney & Dami, unpublished).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 (https://weather.cfaes.osu.edu/). This is approximately 150 to 250 GDD ahead of the 30-year average (Fig. 3).
Fig. 2. Temperature departures from 30-year mean for April, May, and June 2024. Figures from https://mrcc.purdue.edu
Fig. 3. MGDD (base 50F) departure from 30-year average from 1-April to 15-July 2024. Figure from https://mrcc.purdue.edu
Precipitation
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 (https://climate.osu.edu/archive), with exception to NE and NW Ohio.
Fig. 4. Accumulated precipitation from 17-April to 15-July 2024. Figure from https://climate.osu.edu
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
- 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.
- 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:
- 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.
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