What the foot sox are most effective in controlling is the apple maggot fly....which affects primarily apples but can sometimes affect other fruits.
The website I have put up here before is helpful MOSTLY for Eastern Washington. http://das.wsu.edu/
(you have to log in and play with it)
This website is actually fairly accurate if you use an appropriate station (try Vancouver Washington for the Portland area).....that is, it is fairly accurate in predicting the earlier pest to arrive on the scene, the codling moth....which came several weeks ago.
However, it is NOT effective in predicting the arrival of the apple maggot fly in Western Washington or Portland. The models this website uses is accurate for stations in Eastern Washington only at this time for the apple maggot fly but there are too many extraneous factors related to humidity, wetness, etc. that make it difficult to predict the apple maggot fly west of the Cascades.
To be specific, the model for Vancouver Washington would predict the apple maggot fly has not emerged yet. I definitely believe this is not true and I believe that the fly is now flying and laying eggs both there and in Portland.
Marilyn and Dick Tilbury, of Seattle, found their first apple maggot fly on June 28th. Usually they find it even sooner in the Seattle area but the extraordinarily wet June delayed the pest.
I have found a few (but only a very few) apple maggot flies on some of my traps around town in the Seattle area. I am not a professional diagnostician but I am pretty sure, based on experience.
What does this mean? It means that if you are in the Portland area and you have not protected your apples as of yet, you are in a "questionable" area as to whether you are too late....you would have SOME coverage of your fruit at this point, but clearly not on other apples......in other words, if you haven't done anything as of yet, you won't have a completely pest-free crop.
It also means that it is only a matter of it being a week or two before the apple maggot fly will be out in full force.....and in some cases you can actually see this little fly landing on your apples....when they are at the peak of their season.
My opinions only.