Production and pest update brought to you by the OMAFA Apple Team:
Erika DeBrouwer, Tree Fruit Specialist and Kristy Grigg-McGuffin, IPM Specialist
Table of Contents
Grower Grind
Mowing continues, apple fruitlets are growing, some late hand thinning continues and preparation for harvest has begun! Harvest season is getting closer as early regions start to test early cultivars for harvest maturity (I know! It’s hard to believe!).
It’s almost crunch time! As harvest season approaches, our regular What the Crop?! Apple Update will ripen into an every-other-week schedule. Our next update will be August 7th.
Growth Stages
Apples are continuing to size across the province with most regions stating that although there may be less crop, size is looking very good. Terminals have set across the province with some reverting due to significant rainfalls over the past week.
A gentle reminder that terminal bud set is a great time for leaf sampling to be conducted.
Check out What the Crop?! Apple Update: July 17, 2026 for more details.
Clouds Vs. Smoke
Let’s talk about weather and all that comes with it.
Mr. Sun, Sun, Mr. Golden Sun
A big change in skies compared to last week’s update, thankfully (still thinking of all of those affecting by the fires). With harvest getting closer for early regions and early cultivars, making note of sunlight penetration within canopy is critical.
Feel free to check out last year’s article, What the Crop?! Apple Update: July 25, 2025, looking at the challenges with too much sunlight, what damage can occur to the fruit, and how to mitigate this in your orchard. I will leave you with a few points of consideration:
- Drought stressed trees are more prone to sun damage
- Sunburn can be more damaging if there is a week of cool, windy, overcast weather followed by a hot (over 30°C) calm day with full sunshine.
- Consider pulse irrigation to avoid water stress midday.
Rain on my Orchard Parade
Although the sun is back in full force, not all regions are getting the rain they need, or maybe they’re getting too much. Niagara and Brantford regions had extreme rainfall in a short time just a few days ago, where other regions (most notably the southwestern region), have missed critical rains throughout the growing season.
Maps of current agroclimate conditions – Agriculture and Agri-Food Canada
Be sure to stay on top of either pumping out water, or pumping water through your drip lines if you’ve been experiencing some dryness over the past week or so. To learn how to calculate your orchard’s water needs use the article below.
Maturity
Testing for harvest maturity is upon us, do you have you toolbox ready? Consider the following to have a well-rounded kit that aids you in determining peak harvest timing for each cultivar:
- knife, cutting board, spray bottle – essentials when testing fruit for optimal harvest.
- pre-mixed iodine – for starch/iodine analysis (sometimes iodine can be difficult to source, try reach out to your local pharmacist or veterinarian to get the goods).
- handheld refractometer – to measure sugar levels.
- handheld penetrometer – to measure firmness.
- colour charts – to distinguish background colour, these can be accessed through the Ontario Apple Growers.
- great taste buds – to have a bite here and to make sure that you’re 100% confident in your decision.
- patience – to ensure harvest season goes smoothly and that you take each challenge in stride.
More information can be found in the 2024 Summer Issue of ONcore where harvest field tests are gone over in more detail, OR check out last years What the Crop?! August 22, 2025 blog post that briefly goes over each test AND check out the table below that goes over starch and firmness recommendations for ideal harvest for long-term storage.
Cultivar | Starch Index (1-8)* | Firmness (lb) |
|---|---|---|
Ambrosia | 2.5 – 4 | 17 |
Cortland | 2.5 – 3.5 | > 15 |
Crispin / Mutsu | 3.5 – 4.5 | > 17 |
Empire | 2.5 – 3.5 | > 17 |
Gala | 2.5 – 3 | > 18 |
Golden Delicious | 3 – 4 | > 16 |
Honeycrisp | ~ 5 | > 15 |
Idared | 3 – 4 | > 15 |
McIntosh | 2.5 – 3.5 | > 15 |
Northern Spy | 2.5 – 3.5 | > 18 |
Red Delicious | 2.5 – 3.5 | > 17 |
End of the Line
As trees begin to set terminal buds, you can breathe a small sigh of relief – at least when it comes to some insect and disease pressure. Terminal bud set signals the end of shoot growth, and with that comes a shift in how we approach orchard pest management.
Many insects such as aphids and apple leafcurling midge target young, tender growth and move elsewhere or become less of a threat once shoots harden off. Be sure not to let root suckers get away from you though – these pests will just move down to this new growth.
Diseases respond to this shift as well. Movement of fire blight within a shoot slows down significantly after terminal bud set, since the bacteria rely on active growth to spread. Now is a good time to prune out signs of fire blight strikes without trigger excessive new growth. This will help reduce inoculum present in the orchard over harvest time to avoid unwanted spread if there are any times of unsettled weather, including damaging winds or hail.
Powdery mildew is also closely tied to new shoot growth, needing actively growing tissue to infect and loses momentum once elongation stops. Watch for late season reversal and new shoot growth that sometimes occurs as mildew risk will pick back up again. A reminder though, even with mildew-infected shoots present, fruit cannot be affected by powdery mildew at this stage. Fruit infection occurs over bloom.
A Blight And Switch
If you remember our June 19th What the Crop?! update included identifying Nectria twig blight – well, now is the time to revisit that post!
I have been seeing (and hearing about) more branch dieback symptoms across the province, and some growers may be mistaking Nectria for fire blight. If you’re seeing scattered dead shoots or suspected strikes, it’s worth taking a closer look before reaching for the fire blight controls. Correct identification is important since management strategies differ considerably.
Beetlemania Continues
Let it be? Not this time. The only thing climbing the charts right now is Japanese beetle activity!
These metallic beauties (beauty is in the eye of the beholder, right?) can still be found in many orchards, with feeding often concentrated along border rows and in areas adjacent to wood lots, wild grape or brambles.
Continue monitoring susceptible blocks (*cough* honeycrisp) and assess whether feeding damage and beetle presence is continuing after any recent sprays. These beetles tend to move in and out of the orchard through much of the summer, so regular scouting is important.
Check out last week’s What the Crop?! for July 17, 2026 that covered management tips for this chart-topper.
Degree (Days) of Separation
San Jose Scale
Despite feeling like first generation activity JUST ended, crawler emergence for second generation San Jose scale has started in early regions and will continue over the coming weeks. If you are planning to apply a control for this generation, consider resistance management practices and always rotate to a different chemical group than what was used for the first generation.
For more information on registered products or those with efficacy against scale, see San Jose scale on Ontario Crop Protection Hub.
Predicted emergence date of second generation San Jose scale, by region (biofix March 1st, base 10C)
Region | Current Degree Day Celsius (DDC) | Predicted Crawler Emergence (806 DDC) |
Essex | 900 DDC | Passed |
Lambton, Middlesex, Elgin | 754 DDC | July 28 |
Norfolk | 788 DDC | July 26 |
Wellington | 607 DDC | Aug 11 |
Niagara | 785 DDC | July 26 |
Grey | 665 DDC | Aug 5 |
Durham, Northumberland | 661 DDC | Aug 6 |
Ottawa | 687 DDC | Aug 4 |
Apple Leafcurling Midge
Adult flight and egg laying for the second generation of apple leafcurling midge has now ended in all regions and the third generation flight has kicked off. However, once terminal bud set occurs, there is little concern for this pest as they lay eggs in actively unfurling leaves. That said, if root suckering is an issue in your orchard, these later populations will continue to be active on these terminals – with a fourth generation possible into harvest!
For a full list of products with efficacy on leafcurling midge, see Leafcurling Midge on the Ontario Crop Protection Hub.
Predicted emergence date of third generation adult apple leafcurling midge, by region (biofix March 1st, base 9C)
Region | Current Degree Day (DDC) | 5% Gen 3 (942 DDC) | 50% Gen 3 (1160 DDC) | 95% Gen 3 (1459 DDC) |
|---|---|---|---|---|
Essex | 978 | Passed | Aug 5 | >14 days |
Lambton, Middlesex, Elgin | 833 | Aug 2 | >14 days | >14 days |
Norfolk | 883 | July 29 | >14 days | >14 days |
Wellington | 694 | >14 days | >14 days | >14 days |
Niagara | 881 | July 29 | >14 days | >14 days |
Grey | 751 | Aug 8 | >14 days | >14 days |
Durham, Northumberland | 743 | Aug 9 | >14 days | >14 days |
Ottawa | 773 | Aug 7 | >14 days | >14 days |
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