Orchard Outlook Newsletter Vol 21, No 15

Tuesday, July 20, 2021


Table of Contents:

  • Potato leafhopper
  • Apple maggot
  • Spotted wing drosophila in stone fruit
  • Leaf tissue sampling for nutrient analysis
  • Soil sampling for nutrient analysis
  • Nursery practices in propagation
Pest Management Guides 2021

Events and Notices
  • NSFGA Virtual Summer Tour Sneak Peek
  • Agriculture Weather Station Assistance Program - Lunch and Learn July 21
  • Perennia Virtual Field Days!
  • Bitter rot and apple scab samples for AAFC

The weekly newsletter will soon wrap up for the season. Please consider this newsletter as a supplement to last week’s July 13th Orchard Outlook. Refer to last week’s newsletter for ongoing pest pressures but consider the new notes in the current newsletter.


Refer to the July 13th Orchard Outlook for information about apple scab, powdery mildew, fire blight management, and summer diseases. In addition:

  • It's becoming clear that re-entry times are challenging as expected this year (especially with strep applied after Elsa). Planning going into this season and taking note for next season will be key for figuring out a new program to stay protected while working on orchard activities. Allegro has been a good option with the short 3-day REI but keep in mind the 28-day PHI.
  • Always check both the REI and PHI because in some cases the REI for hand harvesting is longer than the pre-harvest interval. In that case, respect the longer of the two intervals.


Insect management programs should be based on grower monitoring and/or scouting reports. Refer to the July 13th Orchard Outlook for information regarding white apple leafhopper, potato leafhopper, aphids, obliquebanded leafroller, and mites. In addition:

  • Potato leafhoppers can transmit fire blight. Their presence in young plantings and nurseries is concerning, especially in areas of active fire blight infections. Insecticides labelled for leafhoppers include Assail/Aceta, Calypso, and Sivanto Prime.

  • Apple maggot
    • Early captures were noted last week. 
    • 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.
    • 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, Assail/Aceta 6 days, Calypso 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.
    • 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. 

  • Spotted wing drosophila 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 peach, plum, and cherry are listed in the Stone Fruit Management Guide
      • PHI varies widely with longer PHIs for Danitol, Harvanta, Imidan, and Malathion (peach/nectarine) and shorter PHIs for Malathion (cherry/plum), Delegate, Exirel, Entrust and Success.
      • Note that the new Entrust and Success labels include spotted wing drosophila for stone fruit. The PHI varies from 1-3 days depending on the crop.
      • Note that through the minor use process, the label rate for Malathion 85E has been increased for cherries to provide control at 855-2500 mL/ha instead of only suppression at the old rate. The new maximum number of applications is also increased to 2 while maintaining the same REI and 3-day PHI.


Refer to the July 13th Orchard Outlook for information about summer pruning/hedging, pruning & training, young trees, calcium nutrition, weed management, nursery trees, and mowing. In addition:
  • In the case of light crop loads, summer pruning controls vigour and it can also divert more calcium to fruit. The practice might help reduce the risk of bitter pit. Remove vigorous shoots in the entire canopy but especially at the top. 

Leaf Tissue Sampling for Nutrient Analysis

Nutrient levels in leaf tissues change throughout the growing season. The nutrient analysis for apple tree leaves has historically been done after terminal buds set and recommendations are based on that specific timing (late July to early August in Nova Scotia). Collecting samples prior to or after the specified period may give inaccurate nutrient level readings. Annual fertilizer applications should be based on tissue analysis reports and other factors such as pruning, vegetative growth and anticipated crop load.


Collect leaves for nutrient analysis after terminal buds set on this season’s extension growth. Complete sampling by mid-August. 

  • The protocol:
    • A sample usually represents a block of orchard 1 to 2 hectares in size.
    • Sample 10 apple leaves from each of 10 representative trees of the same variety for a total sample size of 100 leaves. Sample from the same trees every year to limit the variation between years. Try marking the tree with spray paint.
    • Collect leaves from the mid-point of the current year’s growth from all sides of the tree.
    • Place the leaf samples in a paper bag.
    • If there are problem areas within the orchard, then sample trees in the areas separately.
    • The leaf sample needs to be submitted as soon as possible after collection in order to obtain an accurate nutrient analysis. If the sample cannot be submitted right away, refrigerate until it can be submitted.
    • Always label samples with the grower or farm name, mailing address, phone number, farm registration number, orchard block name, variety and sample number.
  • Take an accurate sample by reviewing some guidelines on 'How to take a plant tissue test'
  • For fees, contact the lab or your choice.

Soil Sampling for Nutrient Analysis

A leaf nutrient test tells you whether a nutrient has been absorbed. A soil analysis, on the other hand, shows what levels are available. If a tree cannot uptake nutrients from adequate soil levels then perhaps your limiting factor is not related to nutrient availability and is more likely related to compaction, nematodes or pathogens affecting the root system. Or more simply, a soil nutrient test could determine a soil nutrient deficiency.


  • Soil samples do not need to be collected on an annual basis but should be collected at least once every three years.
  • Two to four soil cores should be taken at the drip line from each of 10 trees. The soil cores should be mixed and a representative sample placed in a soil box or sealable plastic bag for analysis. 
  • Early August is a good time to sample orchard soil unless the soil is unusually dry or recently leached by heavy rains. If the soil is too dry it is very difficult to extract full 0-15 cm (0-6") soil samples and a better sample will be obtained by waiting until light rain has moistened the topsoil.

Nursery Practices in Propagation

Chip Budding

As August approaches, consider if chip budding could increase the success compared to t-budding. For t-budding, when the bark slips it signifies the time when the tree is in a period of active growth. The cambium cells divide and create new tissues that can be separated by lifting the bark from the wood. T- budding success depends on the bark slipping so poor growing conditions can limit success. For example, lack of water can interfere with growth, tighten the bark, and interfere with t-budding success. Even a slight resistance to bark slipping results in less bud take. For that reason, 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.

Figure 1: Photo taken in mid-June of this year showing the result of t-budding (left) and chip budding (right).

Sanitation (budwood collection, budding, and maintenance)

  • 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 budded rootstocks in the spring for disease symptoms or poor growth. Remove trees with any signs of fire blight infections.

Pest Management Guides 2021

The pest management guides are available online for download. All changes new to 2021 are made in red text.

Events and Notices

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

NSFGA Virtual Summer Tour Sneak Peek

Here's a sneak peek into the Nova Scotia Fruit Growers' Association summer tour in 2021. Visit farms with your host Michelle Cortens, Tree Fruit Specialist at Perennia to hear from local growers about weather stations, root pruning, mechanical weed control and more. Plus, see new perspectives like a bird’s eye view of a 2D planting. Stay tuned for a series of videos in early August of 2021. The bus is leaving soon. Watch the video here: https://youtu.be/PbxAxVymv6s

Agriculture Weather Station Assistance Program - Lunch and Learn July 21

The Nova Scotia Department of Agriculture and Perennia have launched the Weather Station Assistance Program. The objective of the Farm Weather Station Program is two-fold: to encourage producers to install weather stations and adopt new technology tools; and fully utilize the data to make proactive management decisions to mitigate the impacts of climate change and adverse weather conditions. For more information, view the webpage. For questions, register for the Lunch and Learn on Wednesday, July 21st at 12:30 PM. Questions can also be directed to Jody Wipp.

Perennia's Virtual Field Days!

Join us for this year's Virtual Field Days taking place throughout the month of August! Each week, Perennia specialists will host a 30 minute virtual field day, followed by a question and answer period. For more details, click on the link to register.

Refining Horticulture - August 3, 2021, at Noon (Register)
Technology in Agriculture - August 10, 2021 at Noon (Register)
Optimizing Production - August 17, 2021, at Noon (Register)
Livestock Management - August 24, 2021 at NOON (Register)

Bitter Rot and Apple Scab Samples for AAFC

The Plant Pathology Lab of Kentville’s Agriculture and Agri-Food Canada is looking for apple growers who will participate in a province-wide study of the fungal pathogens responsible for bitter rot and apple scab disease in apple. One of the goals of the research is to look at the fungicide resistance profile to find out which fungicides are still effective or not. This is an industry and AAFC funded project. 

Growers who notice either bitter rot or apple scab appearing in their orchard are invited to contact Dr. Shawkat Ali (shawkat.ali@canada.ca) or Shayne McLaughlin (mc615708@dal.ca). Researchers will then monitor the orchard to collect diseased leaves or fruit from the orchard for further study. Samples cannot be collected from the orchard floor due to rapid deterioration. 

View a research update from past work hereParticipants who provide a site for collection of bitter rot samples will have the species in their orchard identified and they will be informed of the fungicide sensitivity profile for that species.

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

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