from the website
http://das.wsu.edu/

From the Vancouver, Wa research station for codling moth here is the what I get:

" Last Updated: 04/23/2012
Degree days since January 1st. = 138

"Current Conditions:
CM emergence is expected in 7 days (=175 DD). Historically first moth is caught between 121 and 220 DD (average 175 DD). Studies show the 175 DD figure used as a biofix does not affect model accuracy compared to using a biofix. "

"Management:
Pheromone traps should be in place before first apple blossoms open or by 100 DD whichever comes first. If using mating disruption, dispensers should be in the orchard before the first apple blossoms open and use a 10x lure for pheromone traps."

"Conditions:
2% of CM adults should have emerged. No eggs have hatched, but they should start being laid 225 DD (50 DD after biofix). "

"Management:
If you are going to use an insecticide that kills CM eggs (Intrepid, Esteem, Rimon), it should be applied between 225-325 DD (50-150 DD after biofix). Using an ovicide at this time allows you to delay the first larvicide application to 525 DD (350 DD after biofix). If you are planning to use an insecticide at an egg hatch timing then a repeat application of the ovicide is not necessary. If an ovicide only control program is followed (not recommended) then two additional applications at a re-treatment interval of 14 days should be used."

I may be wrong (in which case I hope I am corrected) but a very very basic translation of the above post is this:

1. In Vancouver Washington (closer to you guys in Portland) the codling moth is projected to start its first flights next week, the first week of May. There won't be many of them when they first get started. Seattle, fortunately, is still two weeks away from seeing any codling moths flying.
In my opinion the codling moth is NOT the most troublesome pest here west of the Cascades. The more troublesome pest, the apple maggot fly (which is still months away from presenting a problem) is the bigger pest, but in certain places the codling moth can be troublesome and we may need a "heads-up" to be aware of its arrival.

2. Mating disruptors should be place in the trees now if that is the method of control for codling moth. Wilbur-Ellis is one company selling them. I am doing this (although I may be a week late in some places) and am learning more about this. A lot of people pooh-pooh the efficacy of mating disruptors in urban settings (with some reason) but I think if your apple and pear trees are semi-isolated the disruptors may work and I would like to get more data from people. (hint hint).

3. Those using organic insecticides that go after the eggs in the Vancouver Wa area should apply this in two to three weeks.

4. Those going after the larvae itself using a product (like Spinosad) should probably apply a month from now. The moths may start to come out next week, but we are still a ways away from the proverbial worm that bugs the apple. The codling moths still have to mate, lay eggs, etc., etc.

Caveats: My own experience with spraying is about nil and I don't want to be a final guide. Also, ALL of these ideas should be checked with a local nursery where you buy the product that you are using, and it would help to have a basic idea of what degree days means and how this picture could change with the weather. Currently we expect some cloudy days but the second week of May could bring back this nicely sunny and warm pattern we have been enjoying lately....which, while great for the fruit, is also great for the bugs. The warm sunny days means the "degree day" numbers arrive even more quickly.
Finally, foot sox work perfectly and completely well for stopping the apple maggot problem. If that is the only problem you have, you have many many weeks before you need to even worry about protecting the apples. However, if you are dipping your foot sox in kaolin clay and are concerned about keeping out the codling moth as well, then you will probably need to do this in late May or as soon as you can work with the apples.....

IMO and all.

I usually start with Asian pears. I looked at them today and some were almost marble size. That's about when I begin, depending on time. Before then, it's hard to get the sox/ziplocs to stay on the fruit.

They sure have helped with the codling moth, which for me has always been a much worse pest than the apple maggot.
John S
PDX OR