Ants doing the actual damage is doubtful. I suspect that what's happening is that some other insect or pest is causing the damage to your tomatoes, then the ants are getting in, and that's what you see when you look at the tomatoes.

Or, the fruits are cracking (either radial or concentric cracking), again providing the ants a means to enter the fruit.

Dawn is a detergent and can do more harm to your plants than the ants would. Suze9 is right that the ants are there for another reason, you need to look closer to see what the real cause is.

But let's make no mistake about some ant species and their eating habits. Many ants will happily eat fruits, vegetables, seeds, etc. Fire ants, included. The fruits do not necessarily have to be damaged. I'd call this an 'occasional' problem, though. Luckily! ;-)

Odds are you have aphids, ants go after aphid poo, usually a black substance on leaves. (Black Sooty Mold)

If you use Dawn dishsoap, there are 3 known (to me types) Concentrated and anti bacterial plus the other one. DO NOT use the first 2. Also rinse the plants off after about 10 min. with water

The simplest, easiest way to get rid of aphids on plants is with a sharp water srpay, no soap, no detergent, nothing but plain old water.

Well i havent seen any black stuff but because of the heat sometimes they split but!(not all of them) there is most of the time a little perfect circle on the tomatoes and i belive thats how the ants are getting in and eating from there. and it's evil fireants that i find on them.

some tomatoes have a brown rotting spot on the bottom but the ants dont mess with them. can you ever see the aphids on the plants? thank you for your help and your time.

There is a powder you can used called diatomaceous earth that will effectivley get rid of your ant problem.

Sounds like you have blossom end rot, which is from either erratic watering which causes a lack of calcium, or there's just a lack of calcium in the soil, often in clay. a carton of non fat milk watering would quickly help. Then you need to add calcium in compost or storebought calciums in like a surface mulch.

OK i will try theese ideals and see what happens thank you again. i love gardening but sometimes i just have so much trouble i think its not worth it until i taste a fresh vegtable from my garden. thanks.

Gardening is not easy... but nothing of value is. And it's all a learning experience... I have plants die on me all the time and I've been gardening all my life.
You could do it the way my BF does it, find the most boring plants that basically take care of themselves in your zone... but like I said BOOOOOOOOOOOORING! I like the ones that I have to work at, but give me great returns for my effort.

The crack is probably from uneven watering or too much nitrogen fertilizer after fruit set

Did you ever find out how to organically rid the fire ants from your tomatoes? I have the same problem. I tried spreading cornmeal and borax around the nest around the base of the plant. The nest seems to be gone so I'd like to think the cornmeal and borax worked. But it is also a 100 degrees outside so they may be congregating down low in the ground. Pesky little twerps!

Wow I am so late in this discussion. But thanks for the help. The ants in my garden are brilliant. They walk the little web of rope I use to string my peas and cucumbers to avoid the DE that I put on the base of the plants. I can't help but be impressed! I actually admire them. I just wish they'd eat something else like my unwanted weeds. :)

As soon as my tomatoes go red something is eating a large hole out of the inside from the bottom, so they look perfect until closer inspection reveals they are almost hollow - any ideas? Only thing around plants is ants.

Here is a link that might be useful: farming Classifieds

The Tomato Fruitworm comes to mind right off. The same thing as the Corn Earworm and the adult moth lays eggs near the fruit and when they hatch they burrow into the fruit.

Here is a link that might be useful: Tomato Fruitworm

Here's what we're seeing: A lot of small black ants. Occasional small round hole(s) in the tomato. Once or twice I actually saw a tiny ant crawl out of the hole. I don't know if it's even safe to cut off that section of the fruit and eat the rest or not. I tend to think we should throw it away, but I hate to do that - there are quite a few....

I am seeing the exact same thing as Bert. I've tended to think that it's because we haven't had any rain in about two weeks and the ants are looking for liquid. But I really want to know how to stop them. They are forming those tiny holes just as the fruit begins to ripen.

At least cut it open and dissect it... sounds like something is burrowing into the fruit and the ants are just following suit. I bet you'll find some worms of some sort in there....

Here in South Texas, ants will eat anything they can get to & don't need any enticement! As for aphids, the best cure is to leave wasps and yellowjackets alone to eat them.

I have small bees eating into my ripe tomatoes. Any ideas how to stop it

I see small bees eating holes into my ripe tomatoes. Any ideas how I can stop this

I am heartened to hear of others who see ants actually eating tomatoes. I'm tired of all of the "advice" that assures me that ants don't actually eat plants and fruits. Maybe not where they live.... I live in Phoenix. Here, ants will go after all sorts of fruit and plants for the water. Right now, I'm battling ants actually burrowing into and eating the sap from my eggplants (from the plants, not just the fruit.) First I tried spraying water -- they were back the next day. Then I tried diatomaceous earth. It was only a temporary deterrant, killing some ants. Then I set out a small dish of sugar and borax in water. That killed many ants, but not enough, so I've set out a new dish three days in a row. Next, I tried pouring vinegar onto the "ant hill" (no hill, but it is where they are living in the dirt.) That angered the ants, but the next day despite the vinegar, diatomacous earth, and sugar/borax bait, the ents were back to boring into the eggplant stems and joints. So today I mixed up pyrethrin with water for the right concentration and simply sprayed the plant, especially wherever it was being attacked by ants. I don't like using poisons in my garden...but I'm not sacrificing a productive eggplant plant at the end of May.

Yes. My beefsteak tomatoes are bei.g eaten by ants. The hole is about 1/2 inch across, just big enough enough for them to crawl in & dine. When I pick these tomatoes dozens of ants crawl out. How can I keep them off the ripe fruit?