Production and pest update brought to you by the OMAFRA Apple Team: 

Erika DeBrouwer, Tree Fruit Specialist and Kristy Grigg-McGuffin, IPM Specialist

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The 2025 apple season is officially underway! Across many of the early growing regions, apple buds are showing signs of silver to green tip.

WE NEED YOU! We are collecting bud break data from Ambrosia, Honeycrisp, Gala and McIntosh to be used for future production- and pest-related prediction models. Please fill out this survey to help!

With development kicking off, it’s time to turn your attention to early season pest management. Let’s go through the checklist of things to consider:

Apple-y Ever After Starts With Sanitation

The first line of defense for pest management in an orchard is prevention. There is no silver bullet to eradicate something like disease once it becomes well established. Instead, management is about reducing inoculum and preventing spread to healthy trees or fruit.

Cut It

• Prune out dead or diseased limbs, trees or signs of cankers as well as rotten or mummified fruit. These can harbour overwintering pests, such as fire blight, black rot or bitter rot.

Remove It

• Get rid of wood or cull piles, stumps or old bins that may have been in or near the orchard over the winter. These often provide overwintering sites for insects, such as codling moth and plum curculio.

Mow It

• If the ground is dry enough to get the tractor through, flail mow the orchard floor to mulch up leaves, branches and fruit to encourage decomposition.

Note: Spring-applied urea should go on after snow melt, while the tree is still dormant to facilitate leaf decomposition. If buds have already broken in your orchard, urea applications for inoculum reduction are likely not worthwhile. Flail mow instead.

Keep Calm And Copper On

Dormant copper can protect against any bacteria oozing from overwintering fire blight cankers that may have been missed during pruning. Copper is not systemic; its activity is contact only and provides a barrier over the tree to prevent fire blight bacteria from colonizing an area. This means it will only kill bacteria on the surface of the tree as it emerges from cankers with warmer weather. A delayed dormant copper spray will also provide some protection against apple scab.

Residual activity typically last about 7-10 days under ideal spring conditions. However, once rainfall exceeds 2” from the last copper application, it should be assumed all residue has been washed off. Depending on the spring, you may need multiple applications.

Dormant copper such as Copper Spray, Copper 53W, Cueva, Parasol and Kocide can be safely applied up to ¼” green (possibly ½” green) without risk of phytotoxicity. However, the use of a softer copper registered for season-long control such as Cueva could be extended in those early spray timings to ½” green or tight cluster in blocks with low scab inoculum (ie., free of scab last year) to offset the need for other early protectant fungicide sprays.

For some copper formulations, using a dormant oil will act as a sticker/spreader as well as provide efficacy on scale, European red mite and suppression of powdery mildew. This is not the case for all registered coppers. Always refer to precautions listed on the product label prior to use.

A Little Oil Goes A Long Way

Depending on the target pest, the term “dormant” oil can be rather misleading as sprays can be applied from the true dormant state prior to bud break up until pink. Unfortunately, optimal dormant timing for scale is not necessarily the same for mites.

If damage from last year indicated scale is a bigger issue in the orchard, oils need to be applied before or shortly after bud break. This efficacy against scale is significantly reduced with later oil applications for European red mite as they develop a waxy protective layer that impedes the oil from effectively penetrating and preventing respiration. Dormant oil applications for scale are one of the most effective control strategies when applied correctly!

However, if European red mite populations have been the problem, sprays can be delayed. Ideal timing is half-inch green to tight cluster but can be delayed to pink; however, blossoms can be quite sensitive to oil under adverse conditions so consider using a lower rate at this timing. Delayed dormant oil applications can also provide suppression of early aphid emergence and powdery mildew sporulation in overwintering buds.

Dealing with the fluctuating spring temperature can often make timing for dormant oil challenging. Be sure to avoid the following situations to reduce the risk of injury:

• Do not apply oil if frost is forecast 48 hour before or after planned application.
• Allow at least 10-14 days between oil and the use of captan or sulphur products. Oil can enhance penetrant activity of these products, resulting in phytotoxicity.
• Do not apply oil during periods of slow drying conditions that may lead to burning of sensitive tissues.
• Red Delicious, Empire, Mutsu and Ambrosia can be particularly sensitive to bark damage if applied in conditions listed above.