Spraying timing for codling moth varies each year depending on the weather conditions. Here's a note I just got from a grower in the Corvallis area. You can use this advice for this year. I bolded it below. 
----
It’s been an interesting time, with the cold, wet spring (really?) suddenly turning to summer. A lot of my trees and vines sat dormant for much longer than usual, then burst out, trying to catch up.

I only found codling moths in my traps a few days ago, while Brad in North Albany has been seeing them since the end of April, although not in any number until May 13. Nik Wiman of OSU Horticulture has been collecting data for the Willamette Valley, seeing a range of May 10 to May 15 for trapping moths, the date that is used as the “biofix” or starting point for the predictive model for spray scheduling.

Using Nik’s biofix of May 15 for Corvallis (the Botany farm just east of Trysting Tree Golf Course off Highway 34), 3% egg hatch should occur on June 3. This is a good time to use horticultural oil to smother eggs. 20% and 50% egg hatch should occur on June 13 and June 24, respectively. These are good dates for spraying with spinosad, which the larvae need to eat for it to be effective.

The available weather stations in the Corvallis-Philomath area give pretty consistent readings at this time of year, with low and high elevations not too different. However, biofix dates appear to have more effect in the model. For those of you in warmer areas, like Brad, biofix is 2 - 3 days earlier, so adjust your spray dates accordingly. For higher, cooler locations (like me and my neighbors at 700’), I’m ignoring my own trapping (which wasn’t very effective) and guessing a biofix 2 - 3 days later.

Note that these dates are targets to guide you, not fixed absolutes, so spray when you can, and with luck we’ll have plenty of worm-free apples.
----

Here's a general resource if you want more info Managing Diseases and Insect Pests in Home Orchards.  Take a look and let me know if you have any more questions. 

Thank you for the response.   I have always understood that spraying oil in summer was bad.    Is that old information?   Or am I just wrong?‍♂️

Definitely need to take care when using oil during the growing season. There are lighter-weight horticulture oils that can smother insects without affecting the trees. 

Also, carefully read and follow the pesticide label. There will be specifications on when and how to use the oil. Many times there are warnings against using when the temperatures are above a certain point (usually 90F).

Hope that helps!

June 2.     Just east of salem.    Is this codling moth?
Sent from my iPhone



Codling moth eggs are small and aren't laid in groups. Here's an example of an egg on a leaf. Hope that helps! They are really hard to spot!