Today's newsletter focuses on the final stretch of the growing season, with reminders about late-season diseases, apple maggot, and management practices that can influence fruit quality at harvest and in storage. With fruit sizing and adding weight to the support system, now is also an excellent time to take steps to protect trees and trellis from the risk of wind damage. Plus, don't miss highlights from the recent NSFGA Summer Orchard Tour, where growers shared innovative approaches to irrigation, soil health, and orchard efficiency.
Please note that the industry-wide Honeycrisp fruit maturity assessments will be slightly delayed this year due to a personal commitment. I anticipate beginning assessments around August 31 and appreciate your understanding.
Table of Contents:
Weather
- Degree Day Accumulations
- Precipitation Update
- Preharvest Management of Apple Storage Rots and Fungi
- Apple maggot
- Tree Health
- Cover Crops
- On Farm Nursery
- Preharvest Management Strategies - ReTain and Harvista
- Summer Pruning and Hedging
- Reflective Mulch
- Estimating Bin Requirements
- Using a Delta Absorbance (DA) Meter
- Reducing bruising
- Considering watercore
- Avoiding internal browning
- NSFGA Summer Tour Digest - August 5, 2026
Weather
Degree Day Accumulations
Harrison Wright shared that as of August 4, the growing degree days remain close to the 10-year average, but below the 5-year average (with the previous 5 years being some of the hottest growing seasons on record).
Harvest dates are difficult to predict based on degree day accumulations alone. Use harvest dates from similar years as estimates and leave a comfortable buffer for preharvest intervals with fungicides and insecticides.
Figure 1: Heating degree day accumulations for plant (above 5°C) and insect (above 10°C) development from March 1 to August 4 for the past 17 seasons. Provided by Harrison Wright (AAFC).
Precipitation Update
We are continuing our sawtooth pattern of alternatively being either well above or well below the precipitation monthly averages. Harrison Wright shared that July was above average after a dry June. The July total was mostly a result of a few storms in the last two weeks of the month. Certainly a welcome amount of rain!
Figure 2: Monthly precipitation totals in 2026 (triangles) compared with the 25-year average (bar graphs). Provided by Harrison Wright (AAFC Plant Physiology).
Late Season Diseases
Preharvest Management of Apple Storage Rots and Fungi
A well-timed preharvest chemical control can go a long way to prevent storage rots (although it will not make up for lack of earlier protection). Pinpoint scab, black rot, flyspeck, sooty blotch and brooks spot are preharvest issues that infect fruit in the orchard. Fungal spores that land on unprotected fruit can germinate and show up as infections in storage. Preharvest fungicide is your only protection going into storage.Recommendations:
- 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 or possible infection rather than after.
- Late season fungicide treatment is highly recommended in blocks that have leaf and/or fruit scab. Pay special attention to the tops of tall trees that might not have had adequate fungicide coverage. Ambrosia trees in particular are very susceptible to scab and the fruit are stored for a long period of time.
- The group 7 & 11 products Pristine and Merivon can be applied up to 5 days before harvest (and preferably within 2 weeks). They are labelled for the control of scab, black rot, flyspeck, and sooty blotch. The short PHI and good activity are especially helpful for protecting apples being placed in long-term storage.
- Don't put away the sprayer too early! Late varieties benefit from a preharvest spray too. Also, cumulative rainfall of 25-50 mm washes off fungicide protection. Growers who stop their fungicide program early see early symptoms of diseases in storage.
- However, be very aware of fungicide preharvest intervals. Plan for an early harvest when considering chemical PHIs.
- Of course, avoid bruising or wounding to prevent infections of blue and gray moulds. Take the time to educate staff on the proper way to handle fruit.
Insects
Apple Maggot
- 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. Flies emerge over a period of time so for satisfactory maggot control, monitor the presence of apple maggot flies to inform treatment programs. Remember, a single female can lay hundreds of eggs so do not stop treatment prematurely.
- Re-treatment is required every 10-14 days under pressure or cumulative rainfall of 12.5 to 25 mm (0.5 to 1 inch). Danitol and products registered for suppression are expected to have a relatively shorter field residual life of 7 to 10 days. Insecticide residue should be maintained through to the end of August.
- Apple maggot flies are weak flyers so a border/perimeter spray of Imidan near known hotspots may be an approach to help kill adult flies from the source. (Being cognizant of the 22-day PHI and REI restrictions).
- 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.
- Apple maggots pupate in the soil and may not emerge until up to four years later. Therefore, several years of diligent management are required to reduce the resident insect population.
Figure 2: An apple maggot fly on a 1 x 1 inch grid of a yellow sticky trap. The fly has a black F-shaped pattern on the wing that mimic's the shape of a spider's legs. It is slightly smaller than a common house fly and has a white dot in the middle of its back.
Horticulture
Tree Health
- Activities to protect trees from the wind are valuable at this time of the year as trees are carrying the extra weight of fruit.
- Focus on fixing broken posts and checking wire tension.
- Check on aging systems and where posts are too far apart. Improvements for existing trellis might include in-filling posts, installing anchors on the windward side, and temporary reinforcements on the most exposed tree rows.
- Check the height of the graft union above the soil line. If frost heaving has occurred it is recommended that you hill soil to cover exposed roots and an overexposed rootstock shank. An overexposed rootstock shank may be more susceptible to winter injury during fluctuating warm winter temperatures. Exposed roots are also susceptible to herbicide sprays.
Cover Crops
- Perennia has a series of videos about cover crops by Sonny Murray and Rosalie Gillis-Madden that can be accessed from our website.
- For August and September plantings of cover crops, check out the factsheet about Fall Cover Crop Species Selection and Management that was written by Sonny Murray and Caitlin Congdon. During the summer orchard tour, Harrison Van Meekeren shared the importance of making sure the chosen cover crops winter kill if spring planting is planned.
On-Farm Nursery
- It is highly recommended that you water your nursery before and after budding to encourage callus formation and a healthy union.
- Find a source of budwood 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 budwood. Cut budwood fresh every morning if possible.
- Occasionally sanitize all tools used for budwood 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.
- The general recommendation is one part bleach to ten parts of water.
- If bleach is too tough on tools, Lysol and Pinesol at one part product to ten parts of water are good alternatives.
- Do NOT use rubbing alcohol because even at 70% to 99% concentration it allows bacteria to survive (California Agriculture 1991).
Harvest Fruit Quality
Preharvest Management Strategies - ReTain and Harvista
- The economic return for these products is expected to be greatest with good crop loads, high-value varieties, and good fruit quality.
- For local rates and timing, visit our resource on ReTain and Harvista for Gala and Honeycrisp.
- Harvista blocks ethylene action in fruit, even after ethylene has been produced by fruit so it can be applied within a few days of harvest. ReTain requires a timely application to fruit before ethylene production escalates so it is applied several weeks prior to anticipated harvest.
- These products are not expected to prevent the structural stem damage that is associated with broken stem windfalls due to high winds.
- A new online tool is available from Valent: ReTain PGR Apple ROI Calculator.
Summer Pruning and Hedging
Vigorous shoot growth in orchards could present a fruit shading problem. Summer pruning could be used to expose the fruit to more sunlight to improve fruit colour. Also, summer pruning controls vigour so it could divert more calcium to fruit. The practice might help reduce the risk of bitter pit.Recommendations:
- Summer pruning should involve making the pruning cuts to one- and two-year old wood. Remove vigorous shoots in the entire canopy but especially at the top.
- Leave the weaker side laterals to supply the fruit with carbohydrates. If you over prune you could end up reducing fruit size.
- Avoid leaving short stubs as they will produce two or more shoots next spring.
- Hedging done in August after terminal bud set is not expected to result in regrowth this season.
Reflective Mulch
Reflective mulch will help to expose more fruit surfaces to sunlight so that the fruit begins forming red colour pigments. More sunlight exposure can help to maximize red colour which in turn improves fruit quality and harvest efficiency. The reflective mulch may be applied to high-value apple varieties at 2-3 weeks before harvest.
Estimating Bin Requirements
Use the following math to help you estimate bin requirements if the fruit in a block are relatively uniform in size. The crop volume is determined by the number of trees, number of fruit, and fruit size.
To approximate the number of bins required:
- Calculate the number of apples per acre (# trees per acre x avg # apples per tree)
- Refer to table 4 for the # of apples per 17 bu bin of a selected average count size
- Bins/acre = # of apples per acre / # apples per bin for selected count size
Table 4: Number of apples of a selected count size to fill a 17 bu bin.
Example 1: 125 count size
- 1000 trees per acre x 60 apples/tree = 60,000 apples/acre
- There are 2125 apples per bin of 125 count size.
- Bins/acre = 60,000 apples per acre/2125 apples per bin = 28.2 bins/acre
Example 2: 113 count size
- 1000 trees per acre x 60 apples/tree = 60,000 apples/acre
- There are 1921 apples per bin of 113 count size.
- Bins/acre = 60,000 apples per acre/1921 apples per bin = 31.2 bins
Recommendations:
- Now is a great time to consider your bin inventory, repair bins, and ensure bins are well-washed.
Using a Delta Absorbance (DA) Meter
The DA meter is a handheld device used to monitor the chlorophyll content of the apple peel as an indication of fruit maturity. Chlorophyll degrades as the fruit matures so the reading correlates with other changes that happen during the ripening process.
What you need to know:
- Varieties have a unique set of DA meter values associated with them that are the boundaries of when to begin and end harvest, based on local research by AAFC. This means that you cannot test a Gala and expect it to match values set for Honeycrisp. McIntosh and Cortland do not work well with the DA meter.
- DA meter values become smaller as fruit matures. Typically the readings will change by 0.1 units in one week (ex. from 0.6 to 0.5). There may be daily fluctuations so do not take daily readings as the time scale is too frequent.
- The late Dr. John DeLong who spearheaded local research on the topic recorded a podcast with us in 2019 on 'Sensing Fruit Maturity'.
- DA meter readings after Harvista/ReTain might not actually represent maturity. Changes to chlorophyll content caused by these products might not be synchronous with other maturity indicators. Do not rely on DA meter readings on fruit treated with ReTain or Harvista and instead use other maturity indicators.
Using the DA meter:
- Years ago Joan Hebb created a handy Quickstart Guide. Follow the instructions for calibrating and clearing the mean values.
- Leave the fruit on the tree but ensure that leaves are not caught between the LED sensors and the fruit surface.
- Take a reading on the average sides of each apple (imagine an apple has four sides, ignore the sun-exposed and shade-exposed sides and use the remaining two sides).
- Test a minimum of 20 apple samples randomly from each block by measuring 10 apples from one side of the row and 10 apples from the other side (10 apples x 2 fruit sides x 2 row sides = 40 readings).
- Record the average result calculated by the device then clear the mean value to start over in the next block. Keep your mean values because it will be helpful to compare blocks over time and between years. Record the block name and successive dates of measurement.
- Honeycrisp with a DA meter reading above 0.59 is too immature to harvest, 0.59-0.36 is optimally mature and best for storage, and below 0.36 is over mature and susceptible to storage disorders so is best sold immediately (DeLong and others, 2014).
- The DA meter boundaries for Ambrosia destined for long term storage are 0.47 to 0.28 (DeLong and others, 2016).
Recommendations:
- Take weekly observations on the same day to analyze the rate of change. Start taking sample readings 3-4 weeks before the predicted harvest date to anticipate the rate of change and the approaching start time. One of the major benefits of the DA meter is using the readings to chart the progression of maturity and to compare blocks so that more mature blocks can be harvested before others.
- The DA meter values for optimum harvest may vary each year so it is still important to regularly do a taste test and starch test. The DA meter helps to increase the frequency of sample testing and the sample size.
Reducing Bruising
Recommendations:
- Let fruit warm up before harvesting. Apples picked in the cool weather of early morning bruise more easily than those picked in the day’s warmth. Generally, susceptibility to bruising decreases gradually from 0 to 15°C.
- Take the time to educate staff about the proper way to perform harvest activities that reduce bruising. For example, pick the bottom of the tree first, don’t overfill the picking bag, avoid long harnesses that let the bag bump against knees when walking, explain the difference between varieties etc.
- Re-grade orchard roads prior to harvest to lessen bumps that would jostle fruit being transported in bins.
- Have an inspector sample fruit from various positions in the bin two times each week and leave at room temperature for 24 hours to check for signs of bruise development.
- If bins of fruit will sit in the orchard during overnight freezing temperatures, place the bins where they will be shaded from direct morning sun. Direct sun will warm the fruit too quickly and can lead to deep and lasting bruises.
Considering Watercore
Watercore is a fruit disorder closely associated with over-mature apples along with several other factors. It happens most frequently in years with high sunshine and lack of cloudy, rainy days. Also, highly coloured and large fruit are most prone to the disorder. Fruit with the disorder have an appearance of water-soaked flesh because the spaces between the cells become concentrated with sugars instead of air. Small signs of watercore can disappear in storage and add sweetness to fruit. However, more serious watercore can reduce gas exchange in the fruit and lead to internal breakdown.Recommendations:
- Mature fruit are more likely to develop the disorder because as fruit mature the starches are converted to sugars. The sugar solution builds up in the fruit. Blocks that have a history of watercore should be harvested before other blocks.
- Consider products to delay harvest maturity. Both ReTain and Harvista labels state delayed onset and incidence of watercore.
Avoiding Internal Browning
Internal browning is likely related to carbon dioxide injury. The disorder frequently occurs in overmature and large fruit that have high carbon dioxide concentrations. In particular, fruit harvested late in the harvest window are most susceptible because as fruit mature their ability to diffuse internal carbon dioxide concentrations decreases. The internal carbon dioxide builds up and increases the chance of injury. Consider using products that delay harvest maturity.Events and Notices
NSFGA Summer Tour Digest - August 5, 2026
The 2026 Nova Scotia Fruit Growers' Association (NSFGA) Summer Tour brought growers together from across Atlantic Canada and beyond for a full day of learning, discussion, and innovation in the Annapolis Valley. The tour highlighted how progressive orchardists are adapting to changing weather, evolving technologies, and new market demands while continuing to produce high-quality fruit.The day began at Noggins Corner Farm, where participants were challenged to consider some of the industry's most pressing questions: How can growers make every drop of water count? Which rootstocks are best suited to Nova Scotia conditions? How can soil health be improved for long-term productivity? And what technologies will help orchards become more efficient and resilient?
At CAP Farms in Grafton, discussions focused on rootstocks and irrigation. Eric Chappel shared firsthand experiences with a range of rootstocks, highlighting the benefits and challenges of different systems and encouraging growers to compare their own experiences. Standout rootstocks for Honeycrisp included M.26 and G.214.
The second stop at WINK Apples in Billtown showed a new drip irrigation system and innovative soil health practices. Harrison Van Meekeren discussed practical considerations with irrigation for those considering similar investments. Philippe Caron (Dubois) provided a behind-the-scenes look at irrigation infrastructure. Participants also learned about the farm's use of diverse cover crop mixtures, mulching strategies, and soil-building practices designed to improve organic matter, water retention, and orchard productivity.
Following lunch, the tour moved to Stirling's Mountainside Farms, where Tim and Andy Stirling demonstrated how equipment innovation and technology can improve efficiency. Growers gathered for an impromptu demonstration of the front mount mower with back end sprayer. The farm also showed management techniques for producing premium Ambrosia apples, including tying down branches to improve fruit set and cropping consistency. Discussions at a new planting then shifted to moisture conservation, with participants examining the farm's long-standing use of hay mulch.
The final stop at Wittenberg Farm focused on young orchard management. Evan Wittenberg highlighted their seven-wire fruiting wall system where they are also tying down limbs on Honeycrisp and Gala. Further thoughts on irrigation were shared by Tal Weil (Delta Irrigation). Throughout the day, conversations with researchers Erin Smith (AAFC) and Vicky Levesque (AAFC) reinforced the importance of healthy soils.
Congratulations to the Nova Scotia Fruit Growers' Association for a successful tour! Many thanks to growers for openly sharing ideas, challenges, and lessons learned! While every farm is different, the innovation, collaboration, and a willingness to try new approaches continue to be defining strengths of Nova Scotia's apple industry.
Check out the Nova Scotia Fruit Growers' Association on Facebook for more photos and their acknowledgements for generous sponsor support.
Pest Management Guide
We offer printable PDFs of the guides from our website:
Online pest guides are also available without login (https://www.perennia.ca/pest-guides/) and with login on your Perennia account (https://www.farmdatatools.perennia.ca/). Using the online tool you can filter for organic and conventional options, search for key information, and sort based on information of interest.
Edited by Michelle Cortens, Tree Fruit Specialist
Perennia Food and Agriculture Corp.
Perennia Food and Agriculture Corp.
