Season 2022: Weather update, bloom and tissue sampling

Jeff Franklin, from AAFC Kentville, is untiringly bringing weekly updates to understand how the growing season changes and comparing with previous ones. Last week, like the last couple of weeks, brought an important amount of rain, filling the soils of water and leaving a good moisture for grapevines. Mentioned in the previous publication, hybrids, such as Baco noir or Frontenac started bloom last week, while others, like Geisenheim or L’Acadie blanc were slightly behind, which might depend on the vineyard location. On the other hand, vinifera varieties are behind hybrids, which is normal for these varieties in our province.

The first table shows the temperature base 5⁰ C and 10⁰ C from 2019 until 2022 accumulated from March 1 until June 28. At the end of each section, it’s possible to see the average of the last 5 and 10 years respectively.

Category	2019	2020	2021	2022	5 year average	10 year average
Plant development (Base 5ºC)	531.6	607.6	714.8	654.6	616.7	617.9
Insect development (Base 10º)	232.8	325.3	377.6	322.0	309.6	307.3

Figure 1. Degree day accumulations as of June 28, 2022.  All data are taken from the Kentville weather station, based on a start date of March 1, and calculated using the single sine method.

The positive trend continues showing higher values than the average of the last 5 and 10 years, like last week, at this time slightly slower compared the previous weeks. 2022 is lower than 2021 base 10⁰ C, with 322.0 and 377.6 base 10⁰ C respectively. This is possible to be corroborated with the differences in the vineyard as well. If you have records of phenological stages in your vineyard, you will be able to track bloom differences between this and the previous season in some varieties. Even with the slight decrease on degree day accumulation, the current conditions have been quite favourable for hybrids and Vitis vinifera varieties.

In the following column graph, you can see the values from 2004 until 2021 and at the end the average of the last 5 and 10 years respectively.

Figure 2. Degree day accumulations as of June 28, 2022 base 10⁰ C. All data are taken from the Kentville weather station, based on a start date of March 1, and calculated using the single sine method.

The graph shows an increase of temperature in 2022, with higher temperatures than the average of the last 5 and 10 years, even though showing less differences than the previous weeks. Similar pattern as last week, as mentioned before, in 2021 the temperatures were higher than this year until June 28. Compared with other years, 2022 is slightly lower than 2017, while 2020 and 2022 are quite similar until this date.

In terms of rainfall, Jeff informed that the accumulated precipitation until Tuesday 28 morning is 92 mm, compared with the 10-year average of 95 mm. From the last 28 days, 13 days have had precipitation, which has contributed to keep a good moisture in the soil and combined with the warm temperatures, permitted the plants grown steadily the last month. 

The current information confirms that the environmental conditions have high moisture and warm temperatures, which can increase fungal diseases, for example Downy Mildew, in the vineyards. Even though it sounds repetitive, it’s always good to remember to 

• Scout the most vulnerable varieties in locations with lower air flow, more humidity, warmer conditions, and the areas where in previous years the diseases have been found. 
• Spraying might be necessary in some of the products applied, as contact ones might be washed depending on the amount of precipitation received in the area. Therefore, look at the date of your last application before you decide to move forward. 
• Remember to rotate products with the same group to avoid creating disease resistance, pay attention with the re-entry time and keep an eye on the forecast, especially precipitation.

In terms of plant phenology, bloom started in the earliest vines, and this means the right time for the first tissue sample of the season. 

• How to proceed with this? Please, look at the following video and fact sheet Grape Tissue Sampling to have more information on how to proceed. 

• What are the role of the nutrients? You can read a section at the Grape Production guide to get insights about nutrients in grapevines. Please start from page 33, starting with the Grape Tissue Sampling process.

Figure 3. On the left Frontenac after bloom and on the right L’Acadie at bloom.

Figure 4. On the left Geisenheim at bloom and on the right NY Muscat before bloom.

Figure 5. On the left Chardonnay starting bloom and on the right Pinot noir before bloom.