What type of "rot"? Possibly BER (blossom end rot) as many are experiencing this year due to the weather? It can affect all varieties tho not always at the same time. FAQ on it linked below.

Are these plants in-ground or in containers?

Dave

PS: If that is the problem you'll find many discussions going on here about it that you might want to read through.

Here is a link that might be useful: BER FAQ

No, it isn't BER. I had a bit of trouble with that until I limed my soil. That got rid of 99% of the BER.

The Rutger are simply rotting from the inside out, it seems. No puncture or bite marks.

The Rutger are simply rotting from the inside out, it seems. No puncture or bite marks.

*****

If the insides are black it usually means that the problem in internal BER, which is much less common than the typical exterior BER. The fruits look fine, you cut them open and there are black areas, usually around the seed cavities and in the center.

Liming the soil is fine if the soil pH needed adjustment , but added Ca++ is not the prime reason why BER occurs.

And I think that's discussed in the link Dave gave you.

Carolyn

Sometimes BER happens inside the tomato, with no visible outside mark.

Is the tomato black inside (interior BER)?

If not, what exactly are the symptoms?

You say They don't even try to ripen.

Do you mean the rotting fruit on your Rutgers plants are still green?

You might also want to see Carolyn's response on this thread:
http://forums.gardenweb.com/forums/load/tomato/msg0719362614466.html?5

Apparently this is what Pythium fruit rot looks like:
http://www.umassvegetable.org/images/soils_crops_pest_mgt/disease/tomato_pythium_fruit.jpg

Hope I never see it on my tomatoes! The Redheaded Pine Sawfly larva infestation on my mugo pines was enough for this week. *still shuddering*

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Did you know that there is a separate forum for tomato seed exchanges? You'll get more responses there.

Here is a link that might be useful: Exchanges forum

That would be my best guess too - internal BER. It too goes away.

Dave