Orchard Outlook Newsletter Vol. 22, No 14

Tuesday, July 12, 2022

Today's newsletter is largely similar to last week's with a few minor additions. For summer disease management, note that once the 10-day fungicide cover program is reached it is better to re-apply protection prior to rainfall rather than after. For insects, be advised that apple maggot are on the move with the first apple maggot having been captured by Dr. Suzanne Blatt's team in Kentville on Thursday, July 7. Also, products for spotted wing drosophila management in stone fruit are discussed. Considerations for budding in on-farm nurseries are listed. Several events and notices are listed including a new series by Farm Credit Canada on farm transition. 

*** Please note that this will be the last weekly issue of Orchard Outlook for 2022. Orchard Outlook will continue to be published occasionally for the remainder of the season. ***

Table of Contents:

  • 2022 Degree Day Accumulations
  • Apple - Scab
  • Apple - Powdery Mildew
  • Fire Blight - Orchard Management
  • Apple - Black Rot
  • Apple - Brooks Spot
  • Apple - Flyspeck and Sooty Blotch
  • Apple Insects
  • Stone Fruit Insects
  • Summer Hedging
  • Calcium Nutrition
  • Weed Management
  • Mowing
  • Training
  • Young Trees
  • On-farm Nursery

Pest Management Guides 2022

Events and Notices

  • Farm Transition Seminar Series from Farm Credit Canada
  • Nova Scotia EFP Farmer Survey
  • NSFGA Orchard Tour (save the date)
  • On-Farm Climate Action Fund for Nova Scotia and Newfoundland and Labrador is Open


2022 Degree Day Accumulations

The cumulative degree days are still very close to the 5 and 10-year averages for base 5°C and 10°C heat units (Figure 1).
Figure 1: Heating degree day accumulations for plant (above 5°C) and insect (above 10°C) development from March 1 to July 12 for the past 17 seasons. Provided by Jeff Franklin (AAFC).
  • Approximately 2% more plant development heat units compared to the 5-year average, and 1% more compared to the 10-year average.
  • Approximately 7% less plant development heat units compared to 2021, and 4% more compared with 2020.
  • Approximately 1% less insect development heat units compared to the 5-year average, and 2% less compared to the 10-year average.


Apple – Scab

Where primary lesions are present, secondary infections have been occurring and will continue during wetting events of sufficient duration. The minimum wetting required for secondary infections is 3 hours less than the wetting required for primary infections.


  • Folpet (Folpan) cautions
    • Likely the timing for application of this product is reached. The label recommends waiting until 30 days after petal fall to avoid fruit russeting, especially on sensitive varieties.
    • Also note that new to this year Folpan has a 6-day REI for hand thinning fruit.
    • Folpan is not a new product but it is relatively new for use in the industry. It is considered a cousin to Captan and is similarly a hot product that has the potential to cause fruit russetting. Do not use Folpan close to oil sprays or products containing surfactants. Also, be wary of tank mixes with liquid nutrients that are formulated to maximize uptake.
  • Hand thinning REI reminder
    • Be aware of the re-entry periods on the captan-containing product Maestro 80 WSP for planning ahead to hand thinning. High-density plantings with a maximum canopy width of 2 m have an REI for hand thinning of 15 days. Otherwise, low-density plantings have an REI of 24 days for hand thinning. 
    • Allegro has a short 3-day REI but keep in mind the 28-day PHI.
  • Summer Programs - Where the pressure from secondary scab lesions is low, the interval between sprays could be stretched to summer programs (~10 day interval) especially in dry weather. However, note the risk of summer diseases if spray programs are stretched to the limit. Once the 10-day interval has been reached, it is better to re-apply fungicide protection prior to rainfall/possible infection rather than after. 
  • Pre-harvest interval for EBDC fungicides (e.g. Manzate, Dithane): For fruit destined for the United States is 77 days versus 45 days for the domestic market. An application of EBDC on July 12 would require until September 27 to meet pre-harvest requirements for the United States. Even the 45 day PHI is approaching for early varieties such as Gravenstein, Paula Red, and Jerseymac.
  • Always tank mix single site fungicides with a group M for resistance management.
  • Be careful mixing water soluble packaging (WSP) with other products. Do not use WSP in a tank mix with boron and rinse the tank well before and after boron. Carefully review nutrient formulations that might contain boron in small quantities.

Apple – Powdery Mildew


  • Powdery mildew will continue to spread until terminal bud set. Remember that late summer sprays are protectants for new tissue and they are not eradicants on previously infected tissue.
  • Powdery mildew protection should go on prior to a period of warm and dry weather when infections are expected, and not prior to heavy rain. 
  • Do not apply more than two consecutive applications of a group 3 or group 7 fungicide.
  • Pay particular attention to susceptible and high-value varieties such as Honeycrisp and Gala.

Fire Blight - Orchard Management

If you are noticing fire blight pressure this year you are not alone. There were several infection events with EIP above 100 during full bloom that coincided with rainfall. Festering infections from last year offered plenty of bacteria to cause blossom infections where protection was not adequate. Maybe antibiotics were applied to only every second row and coverage didn't reach the floral stigma of susceptible varieties that were protected by fluffy petals, and maybe full control wasn't achieved by post-infection treatment. 


  • Monitoring: 
    • Continue monitoring for signs of blossom infection, especially in young blocks. Monitor for shoot blight on suckers that can infect the rootstock.
  • Pruning:
    • In the case of a manageable amount of infections, timely and frequent pruning of active infections can slow the spread and minimize losses of entire trees. Continue to prune out infected shoots as they appear. Revisit the block every couple of days until no new shoot infections are found. Fire blight will continue to spread rapidly while there is active shoot growth.
    • Remove fire blight strikes at least 2-4 ft below active infections to remove the leading edge of the bacteria. Being aggressive at the first sign of symptoms will help prevent the re-occurrence of symptoms and the need for continuous cutting back.
      • Research by Clarke 1991 shows that when infected shoots are pruned at only the base of visible symptoms, in 57% of cases the infections continue unimpaired. Pruning 0.6 ft beyond visible symptoms results in a continuation of infection in 12% of cases. 
      • Pruning back to at least 2 year old wood is more resistant to infection.
      • If possible, leave a 4 inch stub at a branch union so that a canker would form on the stub rather than on the leader. Cankers are likely to form on the stub so they should be marked (spray paint) for removal during winter pruning.
    • Cut out infections when a period of 2 dry days are in the forecast. Leave prunings in orchard laneways to let dry thoroughly for several weeks. If cutting a whole tree consider letting it dry while attached to the trellis. Don’t make piles that will prevent the wood from drying. 
  • Slowing:
    • If a blossom blight infection occurred, prohexadione calcium is a tool known to slow down bacterial spread in the tree and may buy some time before bacteria reach the leader.

Apple  Black Rot

The black rot fungus infects fruit during warm rains from petal fall to harvest. The highest risk is from petal fall up until 4 to 6 weeks after bloom. Captan is an effective protectant for high density orchards that have a history of black rot. However, consider Captan where practical in terms of label restrictions for re-entry intervals. Merivon has activity but group 7 + 11 products should not be used more than 4 times each year. Fungicides would need to be applied prior to the wetting event.

Apple - Brooks Spot

Brooks spot is caused by a fungus that creates sunken, dark green lesions on the fruit. It is a minor disease that has been an issue on Honeycrisp in the past. The symptoms of Brooks Spot can resemble lenticel breakdown and bitter pit which are also common on Honeycrisp. Include a product for cover sprays that is labelled for brooks spot such as Inspire Super and Aprovia Top, and Folpan.

Apple - Flyspeck and Sooty Blotch

These summer diseases develop on the surface of the fruit in midsummer until harvest. They are caused by fungi that overwinter in dead twigs and the fungi tend to cause more infections under conditions of moderate temperature, high humidity and rainfall. Include a product for cover sprays that is labelled for flyspeck and sooty blotch such as Captan, Maestro, Inspire Super, Aprovia Top, Allegro, Pristine, Merivon and Folpan.


Apple Insects

  • Aphids: Monitor for green apple aphid. In young trees the aphids can disrupt shoot growth. Monitor nursery plantings as well. Now that leaves are curling high water volumes are needed for effectiveness. Green aphid will move back into orchards that were treated previously so continue to monitor. Assail and Calypso also have activity on codling moth, apple maggot and leafhoppers. Be cognizant of REIs if installing trellis.

  • Codling moth:
    • Continue to monitor traps for late moth flight and treat as soon as the threshold for treatment has been reached. If 10 or more moths are caught 7 to 10 days following a treatment then apply a treatment. When the time for apple maggot treatments arrives, the chemistries will also treat late codling moth.

  • Mites: 
    • Scout your orchards or check your scouting reports to see if there is a treatable population. Mites thrive in warm and dry weather.
    • Both European red mite and two-spotted spider mite are controlled by the products Acramite, Apollo, Kanemite, and Nealta. All three mite species are controlled by Nexter and Envidor.
    • This is the time of year to get rust mite under control instead of mid to late August when the foliage has become bronzed.
    • Mites have many generations per year and therefore have a high potential to develop resistance. For resistance management, it is critical to rotate miticide classes. The use of dormant oil applications will also help to delay resistance selection for European Red Mite.

  • Obliquebanded leafroller: Monitor or check scouting reports for larval populations. The caterpillar will feed on terminal shoot growth and also on apples, leaving a scar.

  • Apple Maggot:
    • Dr. Suzanne Blatt and Kim Hiltz at the research station reported their first capture of one maggot fly on Thursday, July 7th. In blocks that are still being treated for codling moth, the control is extended to early maggot flies.
    • The economic threshold is 1 maggot fly per orchard on a yellow sticky board. Apply a treatment 7-10 days after the first fly is captured on a yellow sticky board or immediately after a female is captured on a red sphere.
    • Note the different re-entry intervals for hand thinning: Imidan 30 days, Danitol 23 days, Cormoran 7 days, Assail/Aceta 6 days, Calypso/Theme 12 hr, Exirel 12 hr, Harvanta 12 hr, Vayego 12 hr, and Delegate (suppression) 12 hrs. Note that Calypso has a PHI of 30 days.
    • Clean maggot traps 7 to 10 days after treating a block for maggot and monitor for new trap captures. Retreat if new maggot flies are caught.
    • Significant rainfall will wash off insecticide residues that are needed to ward off apple maggot flies. Re-treatment is required after 10-14 days or cumulative rainfall of 12.5-25 mm (0.5-1 inch). Insecticide residue should generally be maintained through to the end of August.
    • In organic orchards, Surround can be used to deter egg laying and GF 120 fruit fly bait can be used for suppression of adult flies. Both Surround and GF 120 should begin to be applied as soon as flies are present in the orchard. 

Stone Fruit Insects

  • Spotted wing drosophila (SWD) in stone fruit
    • Spotted wing drosophila lay eggs in ripening tender fruit, and larvae may be present at harvest. If monitoring indicates treatment is required, use insecticides weekly. These products rely on contact with spotted wing drosophila adults.
    • Products registered for control of SWD in peach, plum, and cherry are listed in the Stone Fruit Management Guide. PHI varies widely:
      • longer PHIs for Danitol, Harvanta, Imidan, and Malathion (peach/nectarine)
      • shorter PHIs for Malathion (cherry), Delegate, Exirel, Entrust and Success
    • Note that through the minor use process, the label rate for Malathion 85E was increased for cherries to provide control at 855-2500 mL/ha instead of only suppression at the old rate. The maximum number of applications is 2 while maintaining the same REI and 3-day PHI.
    • Note that malathion is registered for use on only sweet and tart cherries and no other stone fruit.


Summer Hedging

  • If your goal is to produce a terminal fruit bud on nonvigorous and dwarfed trees then hedge before terminal bud set in order to get some shoot regrowth. The later you hedge, the shorter the regrowth and the less chance of terminal buds. Past trial work showed that an early July timing at 8 to 10 leaf stage was best for encouraging terminal bud set on Gala/M.9.
  • On vigorous trees, delay summer pruning until terminal buds have been set on vegetative shoots. Pruning prior to this on vigorous trees can promote bud break and weak shoot growth. 
  • In cases with a lot of shoot growth, summer pruning could be a good opportunity to expose the fruit to light and improve fruit colour. Remove vigorous shoots in the entire canopy but especially at the top. 
  • If there is fire blight in a block then there is a greater risk of spreading it by summer pruning than dormant pruning.

Calcium Nutrition

  • Note that nutrient product formulations with calcium may contain boron that would interact poorly with water soluble packaging.
  • Calcium applied at two-week intervals is better than occasional, high-rate applications. 
  • The recommended rate is 4 to 14 pounds of elemental calcium per acre in a season spread over six to eight cover sprays. The percentage of elemental calcium will be listed on the label.
  • Ca has very low movement within the tree and needs to be applied directly to the fruit surface to be absorbed. Therefore, thorough coverage is important to cover developing fruit.
  • Calcium chloride flake (77% Ca) is the most economical Ca material to use but also the highest risk for foliar burn. Apply calcium chloride flake at no more than 4.5 kg per 1000 L of spray solution. The risk of leaf or fruit damage from calcium is highest in hot weather. Susceptible varieties can develop lenticel spotting if damaged. Target fast drying conditions for applications.
  • Risk of leaf injury may be enhanced by Captan. Incompatibility has been observed with Epsom salts, and liquid or emulsifiable pesticide formulations in some cases. Do not apply calcium with apogee.

Weed Management

  • Note that 2,4-D has an 80-day PHI.
  • Prevent herbicide drift by avoiding sprays during wind gusts, periods of dead calm, wind speeds above 16 km/hr, and temperatures above 25°C.
  • Around July the trees are storing reserves in the roots for next year’s growth. When they are storing reserves, late glyphosate applications can be damaging if taken up by root suckers and transported to the root system. Avoid the risk by avoiding glyphosate applications after the end of June.


  • Mowing will help to conserve moisture so that it is not transpired by the large surface area of tall weeds and grasses. Mowing and blowing the clippings into the tree row can also help to conserve moisture.
  • Mowing and herbicide strips help to prevent issues with two-spotted spider mite (John Michael Hardman).
  • Keeping the orchard floor cover mowed will minimize dandelion flowers that attract bees, which increases the safety of insecticide applications.


  • Select strong terminals on young trees and remove competing terminals to single the tops.
  • Training practices should be done on dry and sunny days, especially in high risk fire blight blocks. Wounds can take about 2 days to heal. Do not work in trees when they are wet from dew.
  • Newly planted trees should be pruned for tree structure and supported as early as possible after planting. Prioritize trees that are known to be brittle at the union, including many of the new Geneva rootstocks (G.11, G.41, G.16 etc). This year is expected to be an active hurricane season.

Young Trees

  • Ensure that deer fencing is installed as soon as possible to protect new growth on young trees. Prior to deer fencing, the product Bobbex may be used as a deer repellent but it requires frequent application to new growth and after rainfall.
  • Broadcasting grass seed is not recommended for establishing grass in the alleyway. Direct seeding is recommended to confine the grass seed to the alleyway and avoid spread to the tree row. The herbicide gramoxone used to provide good control of bluegrass species but post-emerge products for grass control are now limited.
  • Remove root suckers. Suckers compete with the main tree for water and nutrients. They harbour pests, and they are an entry point for fire blight. Pull or break off suckers because otherwise cutting them would let them rebound. If necessary, AIM herbicide is registered for control of suckers but avoid drift onto young trees and apply only near mature brown bark.
  • Maintain good weed control during July and August on young plantings that need to develop vegetative growth. Studies have shown that weed competition during this time can have a significant negative impact on early cropping of young blocks.

On-Farm Nursery

  • Budding
    • As August approaches, consider budding methods. T- budding success depends on the bark slipping so poor growing conditions can limit success. When moisture is limiting the bud take is enhanced by irrigating nursery rootstock prior to and after budding. Chip budding can be done with active or dormant rootstock.
    • Find a source of bud wood that does not have a history of fire blight strikes. Trees that have shown signs of fire blight strikes or that are situated near fire blight infections should be eliminated as a source of bud wood. Cut bud wood fresh every morning if possible.
    • Occasionally sanitize all tools used for bud wood collection, storage, and budding by washing in detergent and water and disinfecting with sodium hypochlorite bleach.
    • During bud wood collection and budding, frequently spray hand tools with fresh sodium hypochlorite bleach solution, diluted one part to nine of water.
  • Monitor for aphids and leafhoppers.
  • Remember the importance of weed control in nurseries. Management practices now will impact the outcome of the final tree. Encourage the growing point to be successful!
  • Although Aim is registered for use in nurseries, damage has been reported several times in the past. It is a contact herbicide so it kills tissue on contact.

Pest Management Guides 2022

All changes new to 2022 are made in red text directly on the guides. The information on all changes was summarized in a blog post on April 8th.

Events and Notices

For upcoming events, visit the ‘Events’ tab on the NS Tree Fruit Blog. Specific events will be described here when available.

Farm Transition Seminar Series from Farm Credit Canada

Join Farm Credit Canada for a 9-part virtual event series on farm transition. Hosted by FCC Business Advisors and transition experts, each month will feature a new topic, highlighting a different step in the process.  Registration at their website.

Can’t attend a live event? No problem – check back to watch the recordings at your convenience!

  • July 12, 2022 – Is your farm transition-ready? How to plan and prepare
  • August 9, 2022 – Crunching the numbers: Assessing farm transition financials
  • September 20, 2022 – Value, vision, and goal setting - a farm transition powerhouse
  • October 11, 2022 - Building a farm transition team – how to find the right fit
  • November 8, 2022 - Will and estate planning: The key to any successful farm transition
  • December 13, 2022 - Creating a business plan that fits your farm transition vision
  • January 10 , 2023- Handing over the keys: Transferring knowledge in farm transition
  • February 14, 2023 - Unlock your inner CEO: Leading a successful farm transition
  • March 14, 2023 - Review, revisit, repeat: Keeping your farm transition plan alive

Nova Scotia EFP Farmer Survey

The NSFA is reviewing the Environmental Farm Plan (EFP) - if you have completed an EFP, please take this 5-minute survey to share your insights! https://www.surveymonkey.com/r/NS_EFP


NSFGA Orchard Tour (save the date)

The Production Committee has set the date of the 2022 Orchard Tour as August 11th. This date is later than usual so please mark your calendars. Further details will be released as the tour is finalized.

On-Farm Climate Action Fund for Nova Scotia and Newfoundland and Labrador is Open

A new funding program will help farmers receive up to $75,000 in funding when adopting and implementing beneficial management practices (BMPs) that store carbon and reduce greenhouse gases, specifically in the areas of: 
  • Improved nitrogen management 
  • Cover cropping, and 
  • Rotational grazing 
The On-Farm Climate Action Fund (OFCAF) is part of the Government of Canada's Agricultural Climate Solutions, a multi-stream program to help farmers tackle climate change. Perennia Food and Agriculture Inc. is implementing the fund to help farmers adopt these practices in Nova Scotia and in Newfoundland and Labrador. Training for farmers and agronomists will also be offered over the two-year program, which ends in March 2024. For more information on the program or to apply please visit the website ofcaf.perennia.ca. Deadline for the first intake of applications is July 31, 2022.

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

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