Orchard Outlook Newsletter Vol. 23, No 1

Tuesday, April 18, 2023


First Newsletter of 2023!

I am very appreciative of the turnout for the first meeting of the Orchard Outlook Committee. This morning we had a team of 16 members come to support the industry! In particular, I would like to thank Jeff Franklin for his longstanding contribution of about 20 years on this committee. Please give a warm welcome to our contributors:
  • AAFC - Suzanne Blatt, Keith Fuller, Jeff Franklin, Shawkat Ali, Ian Willick, Vicky Levesque, Karen Burgher-MacLellan, Crystal MacRae
  • Lutz Family Farm - Larry Lutz
  • NSCC - Matthew Vankoughnett
  • NSDA - Colin Hirtle and Jeff Wentzell
  • Perennia - Dustin MacLean
  • Retired AAFC/Consultant - Bob Prange
  • Scotian Gold - Joan Hebb and Danny Davison
There are even more committee members and our weekly contributors will be listed at the end of each newsletter. The Orchard Outlook newsletter will now be published every Tuesday on a regular weekly schedule during the main growing season.

Table of Contents:

  • Winter Weather Review
  • 2023 Degree Day Accumulations
  • Soil Temperatures
  • Cumulative Precipitation
  • Weather Stations in the Valley
  • Apple Buds
  • Apple Bud Cross Sections
  • Peach Bud Cross Sections
  • Sweet Cherry and Plum Cross Sections
  • Apple - Scab



Winter Weather Review

The Environment Canada weather station in Kentville is used for comparison because historical data is available. The average monthly temperatures in Kentville during December and January were several degrees warmer than the 5- and 10-year monthly averages (Figure 1). Then we saw a sudden shift when February was colder than average.

Figure 1: Average monthly temperatures from December through March for the past three winters, and for 5- and 10-year averages at Kentville AAFC.

Extreme minimum monthly temperatures were much warmer than the 5- and 10-year averages in both December and January. The extreme minimum in February was colder than average when temperatures dipped to -22°C (Figure 2).

Figure 2: Extreme minimum monthly temperatures from December through March for the past three winters, and for 5- and 10-year averages at Kentville AAFC.

However, the Kentville weather station doesn't tell the full story! Critical cold temperature events were recorded on the local network of Davis weather stations throughout the Valley on February 4 and in some microclimates on February 26 (Table 1). The temperature dropped rapidly from near 0°C to about -25°C within 20 hours and there was little variation in geographically. Extreme minimum temperatures would be expected to damage buds and trees of all stone fruit crops as we have already discussed in previous post

Table 1: Critical winter temperature events recorded on the NSFGA network of Davis weather stations on February 4 and 26. Note that there is little variation geographically because of the cold air mass and strong winds.

2023 Degree Day Accumulations

This season we have observed below-average temperatures until fairly recently. The degree day accumulations are behind but are relatively close to average (Figure 3). For comparison, this year's degree day accumulations are on track with the year 2019.

Figure 3: Heating degree day accumulations for plant (above 5°C) and insect (above 10°C) development from March 1 to April 17 for the past 17 seasons. Provided by Jeff Franklin (AAFC).

For the following comparisons, please note that early in the season only a few warm events contribute significantly to the accumulated degree days.
  • Approximately 10% less plant development heat units compared to the 5-year average, and 5% less compared to the 10-year average.
  • Approximately 33% less plant development heat units compared to 2022, and 45% less compared with 2021.
  • Approximately 19% more insect development heat units compared to the 5-year average, and 11% more compared to the 10-year average.

Soil Temperatures

The soil temperature is above-average when compared to the previous 10 years (Figure 4). Limited frost in the ground this winter and snow melt by early March has contributed to the warm start in soil temperatures.

Figure 4: Soil temperatures at 35 cm depth at the Kentville Research Station from 2020 to 2023.

Cumulative Precipitation

Figure 5 is a graph of cumulative precipitation over the last ten years including rainfall and the rainfall equivalent from snow. Snowfall in January contributed to most of this year's cumulative precipitation, and the total accumulation is above-average. Precipitation has been lower than average so far in April. However, there appears to be moisture in the soil because of the slow snow melt that limited runoff.

Figure 5: Both rainfall and the rainfall equivalent from snow at the Kentville Research Station from 2020 to 2023. Provided by Jeff Franklin (AAFC).

Weather Stations in the Valley

Perennia continues to provide technical maintenance of the ten Davis weather stations owned by the Nova Scotia Fruit Growers Association through a contract service. The maintenance includes replacing sensors, updating firmware, changing batteries, levelling, and cleaning sensors etc. This spring, temperature sensors have been replaced on all stations on the recommended two-year replacement schedule. If you are concerned with any readings from a station please contact Michelle. 

There are now over 100 on-farm weather stations throughout the province. All stations acquired with provincial funding are named with NSW in brackets and a station number. The stations are publicly accessible on the Davis Weatherlink mobile app. Create a free account to monitor the weather.

Bud Development

Apple Buds

An early region on Middle Dyke Road in the Kentville area is monitored to guide this newsletter. Yesterday on April 17, the Idared buds were at early green tip, Honeycrisp was at scale separation and Ambrosia was at early scale separation (Figure 6).

Figure 6: Bud development in an early region on Middle Dyke Road in Kentville on April 17. Shown from left to right: Idared, Honeycrisp, Ambrosia.

Orchard Outlook committee members report that varieties range from scale separation to green tip in Falmouth, Moschelle, and Morristown. So far this year there appears to be less difference in development geographically than what we usually see. Late sites like Morristown are not as behind as usual.

Apple Bud Cross Sections

In terms of the question of winter injury, Honeycrisp and Ambrosia buds appear healthy (Figure 7, left). Dr. Ian Willick also sampled Honeycrisp, Ambrosia, and Gala shoots and found that they are healthy. 

Stressed trees and those pruned prior to cold snap could have experienced damage. Varieties like Gravenstein, Golden Russet, and Northern Spy are also especially susceptible. I did observe damage to Gravenstein that was pruned prior to the cold snap, appearing as brown tissue supplying the flower bud (Figure 7, right)In this case, the flower buds will likely push and then die. Affected trees will become more clear at bloom as they will expend energy pushing buds and then the rest of the development will be visibly delayed.

Figure 7: Apple buds cut vertically to show a healthy Honeycrisp bud (left) and browning damage to tissue on a Gravenstein tree pruned prior to the cold snap (right). Photos taken on February 9, 2023.

Peach Bud Cross Sections

Many regions exceeded critical winter temperatures for peach buds and injury was visible immediately afterward. Peach buds have a single flower in each flower bud and one flower bud is positioned on either side of a central vegetative bud. A living flower bud is green inside whereas brown tissue is an indication of winter injury. 

In both 2022 and 2023 the flower buds were injured but in addition this year there is also noticeable damage to the vegetative buds (Figure 8). The AAFC Plant Physiology Program also noted little difference in the hardiness of the floral and vegetative buds this year, possibly because peaches are very susceptible to losing their hardiness during periods of warm weather.

Figure 8: Peach buds cut to show brown tissue indicative of winter injury. Two flower buds are on either side of a central vegetative bud. Photos taken on February 9, 2023 (left) and April 11, 2022 (right).

In the case of crop loss, continue to maintain control of peach leaf curl, plum curculio, rot (at least with copper), and scab. Monitor and treat for mites and powdery mildew if they have been an issue.

Sweet Cherry and Plum Cross Sections

Damage can also be expected in sweet cherry and plum (Figure 9).

Figure 9: Sweet cherry bud cut vertically showing damage (left), and plum bud cut vertically showing damage (right). Photos taken on February 16, 2023 and February 9, 2023 respectively.


Apple – Scab

Beginning at green tip, apple tissues are susceptible to infection from the fungus that causes apple scab, Venturia inaequalis. The environmental conditions for an infection are listed in the Modified Mills Table. Primary infections are caused by ascospores present in the leaf litter and infections develop on spur leaves, terminal shoots, and young fruitlets. Ascospore maturity is aligned with bud development so that mature spores are ready to be released when buds show green tissue. If not controlled, primary infections will create spores that generate secondary infections for the rest of the season. The best approach to fruit protection is to control primary scab.


  • If bud development is not yet at the green tip stage, it is not at risk of apple scab infection. 
  • If green tissue was present for today's wetting event then about 2% of total ascospores were available for release, assuming a green tip date of April 15. Within the next five days, about 5% of total ascospores are expected to be mature.
  • Watch for green tissue that would signal the need to apply a protectant fungicide prior to the first infection event and reapply on a 7-day interval, with a shorter interval after wet weather (cumulative 1-2” rain) or rapid tissue growth. 
  • Remember that there is a new label for Manzate (mancozeb). The product may be applied 4 times/ha/year, the re-treatment interval is 7 days, the REI for hand thinning is 35 days (12 hrs for all other activities), and the PHI is now 77 days.
  • If you plan to use oil for European Red Mite control, Captan should be avoided within 7-14 days of an oil application.

Weed Management


  • With early snow melt comes the opportunity for early weed emergence. It has also been a great opportunity for applying residual herbicides to dry ground.
  • Studies have shown maintaining weed free strips from bud break to 30-days after full bloom has the greatest impact on tree growth and yield. Timely herbicide application will ensure you make the most of the weed free window. 
  • Residual herbicides such as Chateau, Alion, and others offer a much longer weed control period than post-emergent products such as Ignite, Gramoxone, and Glyphosate. Chateau should not be applied after budbreak unless application equipment is shielded to prevent crop injury.
  • If weeds are already present, add a post-emerge to a residual herbicide to achieve control.
  • Note that residual herbicides can damage single tree replacements. The Alion label says that individual plants within an orchard may be replanted by removing all treated soil from the transplant hole and refilling with soil that has not been treated.
  • If you are taking out orchard within the next 2-3 years for replanting, avoid applying residual herbicides. The Alion label says to allow at least 12 months from last application to replanting an orchard.
  • If you have had trouble managing grasses, then it is important to treat them early for better control. 



  • Plan ahead and watch re-entry intervals for pruning activities now that fungicide programs are beginning. 
  • Ensure that youngest blocks are pruned first to ensure growth is directed into desirable leader and terminal extension. Prioritize high value trees and then return to low value areas.
  • Pruning may be delayed for vigorous Ambrosia to reduce its vigour.
  • Mature blocks can be pruned later and are best when pruned prior to bloom.


  • Bud break to bloom is the ideal time for granular fertilizer application to maximize tree growth.
  • Target 10-16 inches of new growth each year. More is a sign of excessive nitrogen.


  • Lime especially if a site is being planted this year. When applied in spring the lime works best when applied as soon as possible to get the product working in the top layer of soil. 
  • Surface applied lime will take a number of years to adjust pH of the soil profile so it is best to apply annually or biannually where needed. If soil testing for pH, measure during the same time each year (August) as pH can change over the growing season. 
  • The provincial limestone trucking assistance program is open.

Events and Notices

Pesticide License Pre-Exam Courses by Marbicon

The next series of in-person courses from Marbicon Inc (Jim Jotcham) has been announced. Pre-exam courses (with 5.0 points available T2237).

April 20 - Newcombville Fire Hall in Newcombville, Lunenburg Co.
May 5 - Truro Horsemen’s Club in Bible Hill
More courses are expected in May.

Email/call Jim ( marbicon@eastlink.ca ) or 902-538-7101 to pre-register. More courses can be set up upon demand. Contact Jim if you’d like a course nearer to you and/or at a more convenient date. Pre-exam courses are $125 including HST. People sitting in for 5.0 recertification points for T2237 only pay $110 including HST. Cash or cheque or e-Transfer. Doors open at 8:30am. Food & drink on your own. A course manual is provided.

Pest Management Guides 2023

All changes new to 2023 are made in red text directly on the guides. The information on all expected changes was summarized in a blog post on March 7. 

Edited by Michelle Cortens, Tree Fruit Specialist

Perennia Food and Agriculture Inc.

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