Orchard Outlook Newsletter Vol 21, No 18

Friday, December 31, 2021

Table of Contents:

  • Weather
  • Crop Load
  • Notable Pest Pressure
  • Harvest and Fruit Quality
  • Conclusion
  • Workshops and conferences for the winter season

REVISED POST: This is a re-posting of what was originally published on Dec 22nd to now include the final degree day accumulations for the season. Changes were made to only the weather summary.

This is the final newsletter issue for Volume 21 in the year 2021. Happy holidays everyone!

2021 Season Summary


Degree day accumulations and development followed an above-average trend this past growing season. The gap between 2021 and the 5- and 10-year averages gradually narrowed as harvest approached.

Figure 2: Heating degree day accumulations for plant (above 5°C) and insect (above 10°C) development from March 1st to Nov 1st for the past 17 seasons. Provided by Jeff Franklin (AAFC).
  • Approximately 6% more plant development heat units compared to the 5-year average, and 6% more compared to the 10-year average.
  • Approximately 4% more plant development heat units compared to 2020, and 14% more compared with 2019.
  • Approximately 6% more insect development heat units compared to the 5-year average, and 6% more compared to the 10-year average.

Jonathan Bent, Perennia’s Research Associate, shared some noteworthy trends from the weather this season that can be summarized as follows:
  • The average daily high temperatures trended above-average from May through to October, excluding only July. The average daily low temperatures also trended above average for most of the season.
  • In an average year, Kentville experiences approximately 4 days above 30 degrees C but this year there were 10 days.
  • In Kentville, recorded precipitation was notably above-average in July (96% more), August (59% more), and September (100% more). In June, precipitation was 60% less than average. Several heavy rain events brought significant rainfall.

Crop Load

Bloom of apples occurred relatively early by around May 14th. Weather conditions were not consistent for pollination between varieties and regions, but most were pollinated enough to require thinning. Generally, Honeycrisp bloom was light and uneven and fruit set was variable with heavy fruit clusters in the tops of the trees and lighter crop in the tree bottoms. 

A heat wave occurred at the same time as the optimal chemical thinning period, bringing temperatures in excess of 30°C. In addition, the heat was followed by unseasonably cold temperatures on June 10 and 11, and then a forecast period of rainfall. The overall crop load was good, with overthinning observed in some cases.

Notable Pest Pressure

Due to above average temperatures in early spring, ascospores were quick to mature and consistent wetting produced repeated infection events. This season the wetting events were not long-lasting so there were relatively few heavy infection events but a total of 13 primary infection events were still recorded.  Powdery mildew pressure was high throughout the Valley with the warm and humid conditions contributing to its spread.

Fire blight pressure was notable, due to heat during bloom and multiple trauma events. Most regions were at risk of blossom blight infections on May 26/27 and June 3 to 11. The risk continued for new plantings that bloomed during the summer heat. Trauma blight events were recorded from isolated hail on May 18 and July 21, and after wind from post-tropical storm Elsa on July 10. Orchard activities were delayed by streptomycin re-entry times.

Also this year, spray programs adjusted to new restrictions on captan. Balancing reasonable costs, REIs, and PHIs to get work done in the orchard has been challenging.

A more detailed review of diseases was described in the July 27th newsletter.

In terms of weed control, grasses in young plantings have been challenging and in particular bluegrasses. The seemingly recent occurrence of bluegrass issues could be a result of losing the post-emerge product gramoxone.

Harvest and Fruit Quality

Early in the harvest season the progression of fruit colouring was slow, especially on Honeycrisp. Warm temperatures early in the harvest season slowed down the process of colouring by slowing down production of the pigments (anthocyanins). However, the heat promoted continued ripening of the fruit and hastened harvest activities. In our local industry, there have been good reviews on using ReTain and Harvista to delay maturity for harvest management, especially for managing the maturity of fruit in the second pick. Local research results on these anti-ethylene products are also now available in a report produced by Dr. Harrison Wright, AAFC.

Also this year, fruit growth seemed to continue unconstrained with ample precipitation and heat. As individual fruit size increased it changed the volume of the crop, leading to large apples that filled the bins quicker. Large apples increased bin, storage, and processing requirements beyond what was originally estimated. 

Dr. Wright also shared with me his take on this year's fruit size and maturity from the data they collected in their multi-year research. He explained that the fruit this year were larger but they were relatively less firm and had lower Brix (sugar) and starch levels. This year's quick conversion of starch might be partly attributed to low starting levels rather than only advanced maturity. Low starch levels were likely the result of above-average and consistent rains, and the fact that frequent cloudy weather could impact solar radiation and reduce photosynthesis.

In terms of fruit surface issues, some fruit were rendered unmarketable by isolated hail events throughout the summer that cut or bruised fruit. Also, bitter pit was a widespread observation.


Except significant management challenges, the growing season in terms of the weather was conducive to a good crop.

Events and Notices

For an ongoing list of events including workshops and conferences for the winter season, visit the ‘Events’ tab on the NS Tree Fruit Blog. Take note that some events might be changing from in-person to virtual or a hybrid approach in response to new COVID protocols. Here's a snapshot:

Edited by Michelle Cortens, Tree Fruit Specialist
Perennia Food and Agriculture Inc.

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