Posted: 05/08/2012 at 11:04
Are they "black holes" or sunken black patches at the blossom end? On the bottom of the tomato? If so, it's probably Blossom End Rot. Here's what it typically looks like:
The plum-type varieties like Roma are extremely susceptible to it. No one knows why. I've had Roma plants plagued by BER growing right alongside beefsteak varieties - identical soil, identical watering, etc - that haven't shown the slightest sign of BER.
If that's not what you've got, can you post a photo?
Whether you've got a fungal or bacterial problem, spraying now isn't going to help the already-infected foliage. If you have unaffected foliage, spraying will help against infection. That Bayer product seems to be copper-based, one of the traditional anti-fungal ingredients. Spraying doesn't kill the spores. Effectively you're coating the leaves to put a barrier between the spores and the leaf surface, stopping the spores getting a grip. So you have to spray every leaf and on both sides. Spray about once a week, re-spraying if it rains.
As I said, Romas can present their own challenges, but I wouldn't give up on the plants by any means. They sound like they're in pretty good shape despite the problems and worth fighting for.