Weekly Vineyard Update

 Hello Dear Readers, and welcome to the weekend!

I wanted to give you a quick update this week as we proceed with harvest. Below is the precipitation, GDD and phenological information from the Kentville Research Centre.

Table 1.  Precipitation totals for the Kentville Research and Development Centre by month.

Month	25-Year Average (mm)	Current Year (mm)
April	81.5	54.0
May	74.0	29.8
June	95.5	83.0
July	81.3	201.7
August	94.5	30.1
September	104.1	65.5**
October	115.8

**Up to September 19, 2024

Table 2. Growing degree days up to September 19, 2024. All temperature data were recorded at the Kentville Research and Development Centre.

Single sine degree days, base of 0 °C starting on April 1		Growing degree days, base of 10 °C starting on April 1
Current Year	10-Year Average	Current Year	10-Year Average
2702.8	2604.17	1143.1	1043.2

 

Table 3. Phenological stages of three varieties of grape by date for the KRDC Research Vineyard. Bud break for all three varieties was between May 18 and May 20, 2024.

Date of Assessment	Marquette	L’Acadie blanc	New York Muscat
19-September	Berries not quite ripe	Berries harvest ripe	Berries harvest ripe

 

Table 4. Post-veraison brix and acid values of three varieties of grape, by date, for the KRDC Research Vineyard. TA is the total acidity expressed in grams per litre and measured by titration using a Hanna (model#  HI 84502) titrator.  Brix is total soluble solids (sugar accumulation) expressed as % and measured with an Atago Digital Hand-Held Pocket Refractometer.

Date of Assessment	Marquette		L’Acadie blanc		New York Muscat
	Brix (%)	TA (g/L)	Brix (%)	TA (g/L)	Brix (%)	TA (g/L)
19-September	23.0	15.6	20.0	12.9	18.6	6.7

My own measurements are below: All samples have been sent to the Acadia Wine Lab for analysis. All samples were harvested and assessed on 17 September 2024.

     Variety               BRIX             TA

L'ACADIE	20	10.25
FRONTENAC  BLANC	20.5	22.41
OSCEOLA  MUSCAT	20.9	12.05
NY MUSCAT	17.8	7.06
CHARDONNAY	17.8	15.35
MARQUETTE	21.5	15.69
PINOT NOIR	17.2	15.44

 

In terms of noting other occurrences in vineyards, I have observed some Late-Season Bunch Stem Necrosis (LBSN).

    

                        

 Marquette

Late-Stage Bunch Stem Necrosis:

Timeline:

The bunch stems shrivel during ripening, followed closely by berry shrivel. 

Cause and Development:

Late-Stage Bunch Stem Necrosis (LBSN) is a physiological problem that happens in response to stresses in the environment (eg: excessive rain, frost, freeze the previous year).  

Stress causes the plant’s xylem (the “veins” of the plant that transports water and nutrients) to shut down in the cluster during ripening. With a dead xylem, water cannot be transported to the rest of the cluster. The bunch stems dry first, followed by the berries drying up as well. This means that developing treatment recommendations is a complex, long-term task that may vary by vineyard.

Please note:

·       Late Stage Bunch Stem Necrosis is NOT a disease, so fungicides are not effective against it.

·       LBSN should not be confused with diseases that cause mummies, such as black rot and bunch rot.

     Other Seasonal Diseases and Pests:

     Please do be on the lookout for Botrytis and Sour Rot especially in the susceptible varieties. As currently observed, there does not appear much damage, but do be vigilant as both affect berry quality, the subsequent fermentation and resulting wine.

Again, I will be on the road next week, so if you would like a visit, please let me know. Monday, I will be in the Malagash Area and Wednesday South Shore.

Thank you all for your time this week, and happy harvest!

Cheers!

Katarina

Sources:

Klodd, Annie. University of Minnesota Extension Service. Grape Breeding and Enology
Tracking Down the Causes of Bunch Stem Necrosis | Grape Breeding and Enology (umn.edu)

Katarina Vucic MSc DipWSET

Viticulture Specialist
Perennia Food and Agriculture
Email kvucic@perennia.ca
Office 902-678-7722

Cell 902-599-1390

www.perennia.ca

YIELD ESTIMATION: Timing and Importance- Why is this Practice Useful?

 Following our best practice session, I thought it would be prudent to have this document on hand and bring attention to this topic. It is useful to discuss and clarify any misconceptions regarding this important practice.

As you read, you may recognize that you may not go into as much detail, but it is useful to understand each component of yield estimation, how we derive these numbers and why it is important to do the count each year. 

Remember, each vintage is different, and yield differs annually. It is not useful to base your current yield on previous yield numbers. What the historical average does do is provide a benchmark for a particular variety at your specific site.

If you have any questions, please don’t hesitate to contact me.

So, What is Yield?

Typically, the weight of fruit over a given area (tonnes/acre of grapes). In some cases, yield may refer to the amount of fruit on an individual vine.

Why is yield estimation important?

Yield estimates at or near veraison  help growers to make important decisions that can affect the end quality and quantity of the grape harvest.

Purpose of Yield Estimation

The practice helps vineyard managers to:

• Pre-determine harvest yields in anticipation for processing.
• Make fruit thinning decisions and crop load adjustments, manage vine health and balance their vines as early as possible.
• Improve harvest scheduling.
• Allocate winery space.

·       In the winery, early estimates assist with purchase of goods and supplies necessary to process the crop. Scheduling and coordinating processing and tank space is critical in keeping the work-flow of a winery under control. 

      Yeast, fining agents, barrels, and tanks all need to be ordered and ready by the time harvest begins.

The amount of fruit in a vineyard, which is the most common form of yield presentation (tonnes per acre) is often dictated by contract specifications.

·       Taking both business and viticultural factors into consideration, the appropriate crop load for the same site can vary from year to year.

·       The long-term mismanagement of crop load can have negative consequences.

Over-cropping vines can lead to:

• A vine’s depleted carbohydrate reserves for survival  (which are necessary for overwintering and spring growth).
• Reduced potential bud fruitfulness by stressing the vine during fruit bud initiation            (beginning post bloom through to veraison) . If vines are repetitively over-cropped year after year, it can make the vine susceptible to becoming unfruitful  and may lead to shortened life span.

Under-cropping the vine can lead to:

• Management challenges of unregulated or overly vigorous vegetative growth. Under cropping requires too much vine growth adjustment ( excess  need for hedging, shoot thinning and topping, etc.)
• Wasting photosynthetic energy which is used for vegetative growth instead of reproductive growth.  The result of under cropping  can lead to an  excessively large canopy, excess shading, oversized leaves  and increased disease susceptibility (mildews , rots, and other pest pressures ) and making pesticide coverage very difficult . Such canopies can lead to less mature and unbalanced fruit potential.

Crop Estimation Timing and Method:

Crop estimation can be performed several times during the year, but ideally should take place around veraison. 

The traditional method uses current season cluster counts and the average cluster weight from the previous season or from averages determined from multiple years of weighing clusters at harvest. However, yield will vary from year to year, and it is important that yield estimation be conducted for each block/cultivar for each vintage.

Yield Estimation Factors:

• Planting density (# of vines/ acre)
• Number of producing vines/acre
• Average number of clusters/vine
•  Average cluster weight

1.      Number of Producing Vines per Acre

This is determined by row and vine spacing. The number of missing/ damaged/ new vines/ under-producing vines must also be taken into consideration. Therefore, the number of actual vines may be lower.

2.      Number of Clusters per Vine

This number varies with the level of canopy management. For example: increasing the severity of pruning, shoot thinning or cluster thinning may decrease the total number of clusters per vine. Number of clusters can be counted as late as pre-veraison. The more vines you sample, the more accurate your numbers will be. Remember, all clusters on the selected vines must be counted. Select the vines in an even way; for example: every 25^th vine in even rows (Dami and Sabbatini 2011). Do not select damaged or under-producing vines when counting. You are looking for a representation of “average” vines to represent the whole block.

Alternatively, you may also count the number of clusters per 1 meter of row length at multiple locations throughout the block for each cultivar   

3.      Cluster Weights

Cluster weights also vary with each vintage. Wet weather during bloom, dry summers and disease infections (black rot, powdery mildew and downy mildew) all may cause poor fruit set and have negative effects on berry weight.

Average cluster weights must be obtained from the same vines where cluster numbers were counted.

Obtaining cluster weights at harvest is not used to predict yield in the current season, but to provide a data base for estimations in subsequent years.

Harvest Cluster Weight Method.

This method depends on consistent cluster weights from one season to the next. Components of yield vary each year depending on the weather, site, variety and cultural practices:

PY (predicted yield) = (ANV x NC x CW) / 1000 

Where  PY = predicted yield (tonnes per acre)

ANV = actual number of vines per acre

NC = number of clusters per vine

CW = cluster weight (in kg) ( for example 125 grams = 0.125 kg)

 

If ANV = 1050, NC =25 and CW (avg for primary and secondary clusters is 125 grams 

 Then PY = (1050 x 25 x 0.125)1000

                   = 3.28 tonnes per acre         

Whether you do the estimation early in the season, or pre-veraison, it is important to remember that every year is different and the predictions will not be the same as the previous year.

I hope this is helpful in shedding some light to this crucial annual practice.

As you are probably aware, harvest is slowly underway, so again, if you have any questions, please don't hesitate to contact me. I will be on the road for most of next week- Malagash and South Shore, so if you would like a quick visit, do let me know.

Thank you for your time.

Cheers!

Katarina

Katarina Vucic MSc DipWSET

Viticulture Specialist
Perennia Food and Agriculture
Email kvucic@perennia.ca
Office 902-678-7722

Cell 902-599-1390

 

www.perennia.ca

 

References:

Barriguinha, André et al. Vineyard Yield Estimation, Prediction, and Forecasting: A Systematic Literature Review. https://www.researchgate.net/publication/354418517_Vineyard_Yield_Estimation_Prediction_and_Forecasting_A_Systematic_Literature_Review

Sabattini, Paulo. Introduction: Crop Estimation and Vine Growth. Predicting Harvest Yield in Juice and Wine Grape Vineyards - MSU Extension

Komm, Brittany et al. Vineyard Yield Estimation. Washington State Extension. https://www.vineyardteam.org/files/resources/Vineyard%20Yield%20Estimation-%20WSU.pdf

Kurtural, S. Kaan and S. Brandon O’Daniel. Crop Estimation in Vineyards. https://publications.ca.uky.edu/sites/publications.ca.uky.edu/files/ho86.pdf.

 

 

 

Veraison to Harvest: Grape Cluster Sampling Strategy

 Hello Dear Readers!

I hope the last couple of weeks have been treating you well. The weather has been wonderful, and harvest has slowly started. As we head into the home stretch, I thought it would be useful to focus on sampling strategy for this week. This post will be available as a fact sheet on the Perennia website soon. 

The petiole sampling fact sheet is now available online. I will be on the road for the duration of harvest and dropping in to see you, so if you would like a visit, or a check-in, do let me know.

Thank you and Happy Harvest!

GRAPE SAMPLING STRATEGY

Cluster sampling for fruit maturity after Veraison and up to harvest is one of the best techniques for monitoring and tracking crop maturity.

Grape Quality is Impacted by:

• Maturity and condition of the grapes
• aroma/flavour and phenolic characteristics
• harvesting methods, transportation and processing protocols.

Grape quality parameters agreed upon between the grape producer and the wineries are the foundation for management decisions throughout the year.

Grape quality must be defined in terms of attributes suitable for a particular wine type and style.

A SYSTEMATIC SAMPLING STRATEGY

Berries Ripen at Different Rates

A crop with asynchronous clusters or berries features a range of developmental stages, leading to a mix where some berries achieve optimal sugar levels while others may be less ripe. The key to a good estimate of fruit maturity is collection of a sample that is truly representative of the entire harvested unit.

BEFORE YOU BEGIN: EQUIPMENT NEEDED

• Plastic Zip-lock bags
• Marker (label the bags prior to placing berries/clusters inside)
• Cooler and cooling blocks/ ice (if transporting the samples long distances)
• Refractometer and lab (or sending samples to the lab)

SAMPLE SIZE REQUIREMENTS

Large enough sample, sampled randomly. The goal is to objectively represent the entire crop that will be harvested and processed. (10-30 CLUSTERS PER BLOCK)

                                         

SAMPLING METHOD

There are two basic choices in fruit sampling:

CLUSTER OR BERRY sampling.

With cluster sampling, a further choice can be made by gathering clusters from throughout the vineyard, or using one or more targeted vines.

         Berry Sampling                                                                           Cluster Samples in Cooler

CLUSTER SAMPLING METHOD

Label Sampling Containers First

• Depending on variation, sample approximately 30 clusters per sampling region. (Sample at least 10 clusters from a block)
• Plan distribution in advance and stick to the plan. Skip end vines, perimeter rows, and atypical vines. Alternate left and right sides of the aisle.
• Facing the vine, rotate sampling from the left, center, and right positions on the vine. Alternate canopy depths (near vs. far).
• Alternate between high and low position on vine. Use “blind” cluster choice.

             Crush and juice grapes thoroughly before straining, tasting, and analyzing. 

Record data and note trends.

• Pictures below illustrate the progression of cultivars from veraison to maturity.

BEST PRACTICE

• Sample and taste often in the days and weeks leading up to harvest.
• Do not sample during and right after the rain.
• Be aware that weather  such  as heat spikes or rain events will affect results.
• Crush and juice samples thoroughly.
• Smaller berries and those on the interior of clusters are often left intact and will bias your sample.

• Below is an example of a lab result illustrating the sugar accumulation at the start of veraison.

SOURCES OF BIAS

Please try to avoid these sampling pitfalls.

• Sampling from only the sun-side or only the shade- side.
• Sampling only clusters near the outside of the canopy.
• Sampling the largest, most obvious, or easiest-to- grab clusters or berries.
• Sampling from diseased or other non-representative vines.
• Sampling from end vines and perimeter rows. 
• Sample processing that doesn’t thoroughly crush the berries and homogenize the juice.

Remember: Collecting samples RANDOMLY is KEY.

Thank you all for your time and see you soon!

Cheers!

Katarina

Viticulture Specialist
Perennia Food and Agriculture
Email kvucic@perennia.ca
Office 902-678-7722

Cell 902-599-1390

 

www.perennia.ca