I have had the problem also but now I buy my plants from a local
Greenhouse not a big box store. I plant First Lady II, Champion,
Delicious and Celebrity which are all resistant. I mulch with landscape
material and use 5 ft cages. When the plants start setting fruit I
remove the bottom limbs, about 4 or 5. I spray about every 10 days with
a commercial fungicide and aspirin water. I spray of a evening after the
sun is off of the plants, 3/4 of a aspirin to 1 gal. of water and mix
right with the fungicide. Never water the plant just the root system.

Mel & Donnie down in Bluebird Valley In the middle of beautiful down
town Yountsville. Managers of the water works.
http://community.webtv.net/MelDKelly/doc

http://community.webtv.net/MelDKelly/MelDonniesBluebird