Need more detailed description to help. Also pictures would be excellent. But here's a wild guess. Perhaps aphids?

If you're still looking... I have had good luck with Spanish-sounding varieties. They might be Italian or Mexican - who knows? In particular, Muchamiel, Rio Grande, and Tres Cantos did real well for me this year. They are smaller and not quite my preffered flavors, but they will produce for you. At least they are bigger than cherry tomatoes, which grow under any conditions...

Hi Everyone! I could talk about tomatoes all day, especially when it is too hot to be outside! Patty, Large-fruited tomatoes (pretty much anything that makes tomatoes larger than ping pong balls) will bloom and set fruit (for the most part) only when daytime highs are lower than about 92 to 95 degrees AND nighttime temps are warmer than 55 but lower than 72. So, if you watch your temperatures every spring and fall, after a few years, you'll know by "how it feels outside" if your large-fruited tomatoes are going to set fruit or not. Some years in Oklahoma, that window of opportunity for fruit set is very small. Other years, it is better. This year, we went from "too cold" to "too hot" so quickly that a lot of people have had a disappointingly small OR late OR both fruit set. You WILL sometimes see flowers form at high temps and still not get fruit, and that is because the pollen gets sticky and won't move from one place to another within the flower. Shaking the plant or thumping the flowers sometimes helps you get fruit set in those cases. The foliage is ALWAYS beautiful in June. Partly it is because May and June usually have abundant rainfall, partly it is because diseases and insects haven't gotten to the plant yet, and sometimes it may be because the plant has been fed a high-nitrogen plant food. If nitrogen is giving you gorgeous foliage, it also is depriving you of fruit. As far as giving your plants the sunshine they need AND the shade that helps them survive the heat, I have found that my plants perform perfectly well, stay healthy, and produce plenty of fruit on only 6 to 8 hours a day. Since the sun comes up here at roughly 6:30 in the summer months, and sets at roughly 8 to 8:30, you could situate your plants where they get some shade from a fence, tree or building and it would help them more than it would hurt them, as long as they get 6 to 8 hours of sunlight. My favorite place to plant tomatoes gets sun from sunrise until about 2 or 3 p.m. and then gets some dappled shade from a large pecan tree. The section of the garden that gets shade from mid-afternoon on always produces more fruit later in the season, on both pepper and tomato plants, and I think it is because that late-afernoon shade helps them handle the heat. Also, with some shade, you're less likely to see sunscald on tomatoes, peppers, eggplant or melons. Ssimon, The heat-related fruit set problems I described above to Patty are probably why you have fruit on your cherry tomatoes, and there isn't much you can do about it except pray for a "cold front" to cool off your part of the state for a few days. The only way to beat the heat here in southern Oklahoma is to plant as early as is humanly possible, which for me means early March, about 3 weeks before our average last frost date. Once you plant early, you have to be willing to cover them up anytime the temps are going below 40 degrees (frost can form at 38 or 39 degrees if the conditions are just right). By planting early and protecting my plants, I usually get great fruit set, and am usually harvesting by late April. And, I have to emphasize, that getting ripe tomatoes by late April is my goal and everything I do is geared towards getting early fruitset. I also raise my own plants from seed, starting on Super Bowl weekend, and have very large, very healthy, very well-rooted plants by the time I set them out. THAT is the only way to beat the heat, because some years it gets too hot as early as May and greatly impedes fruit set. This May, we had a hard freeze at our house the first week of May, and then a couple of weeks later we had several days with high temperatures of 98 and 99 degrees. With weather like that, it is a wonder we have any tomatoes at all. For what it is worth, Black Krim and Cherokee Purple both USUALLY set fruit for me through mid-July, most years, and do set fruit later than many other tomatoes. This year has been odd, though, and neither of them is bearing as heavily as usual. Early blight is a perpetual problem in my garden, but not a huge problem. The more tomatoes you grow, the bigger a problem it is. I create most of my own problems by growing too many tomatoes, placed much too closely together. I do keep my plants pretty healthy by mulching heavily, organically amending the soil, watering with soaker hoses instead of an overhead sprinkler, etc. I do major companion planting and garden organically too, which helps. I'll always have some early blight, though, as long as I grow huge numbers of plants. This year, overall, if I were rating the current Early Blight problem on a scale from 1 to 10, with one being minor and ten being major, I'd say this year is a 1 or 2 so far. I have never lost a tomato plant to fusarian wilt or verticillium wilt, or to bacterial speck or spot, etc. I did lose one plant to southern blight in about 2000 or 2001, and lost one to curly top virus around 2003. I've never had trouble with Tomato Yellow Leaf Curl although it is has been found in Oklahoma (it is a devastating disease). Having early blight in our temperatures and humidity is not at all unusual and I can deal with it. I don't use chemical fungicides because they only buy you maybe 3 extra weeks of production and I just won't put chemicals on food we're going to eat, but that's just me. Everyone has to decide for themselves whether they are going to spray their plants for any problem, or not, and I am not saying my way is the best way--just that it is the method I have chosen. Mick, OK, you have me figured out. Somewhat. I have gardened my entire life (dad, uncles and grandparents were gardeners!) and the goal has always been to grow huge amounts of tomatoes to share with everyone we know. So, when I carry sackfuls of tomatoes to friends, family, neighbors, etc., I am just carrying on a family tradition. I HAVE really and truly cut back though. After we moved here, for the first time in my life I had all the room I needed to grow all the tomatoes we wanted. There was plenty of space to experiments with "new" ones. I have taken advantage of that to try many, many varieties in an effort to find the ones that (a) taste best and (b) grow best in our climate. Some years, I have had as many as 400 plants and 100 varieties. This year, it is about 70 varieties and a total of 140 plants for spring. In the fall, it will be fewer varieties and fewer plants, but still lots of them...and probably too many. For next year, I want to cut back to 50 varieties and 100 plants. Now that I know what grows here, and how well they do and how they taste, I am working on paring down the list to "the best" and "the most worthwhile". For a long time, tomatoes have dominated my garden and, even though I love tomatoes, I want to grow more of other stuff too. I gave up most cool-season crops like broccoli, spinach, cabbage and lettuce about 7 or 8 years ago because we couldn't keep the deer from devouring them in the late winter to early spring. Now that I have a deer-proof fence (so far!), I will be able to grow cool-season crops as well and that will take space away from the tomatoes. Will I ever go back to planting just a couple of varieties? Absolutely not. Heirloom and open-pollinated tomatoes make up the majority of my tomatoes and the only way I know to describe the flavor variations between them is to say that heirloom and OP tomatoes are like wines--every one has its own unique flavor. With hybrids, it seems that many (but not all) of them taste about the same as every other hybrid. And, while we are on the subject of wine, did you know that you can make wine from tomatoes? (I am a treasure trove of tomato trivia.) I would love to have two separate gardens, and be able to grow crops in one of them one year, and then rotate everything to the other garden the next year. In the "off" year, I could grow cover crops to enrich the soil, or cover and solarize the beds if needed. However, since I have brick-hard red clay that requires huge amounts of organic material to turn it into good soil, I don't think I'll ever have a second garden. It is hard enough to continually enrich and improve the existing garden. I don't practice very much crop rotation in my garden and, except for the problems with Early Blight, I don't seem to have any real problems that you could blame on a lack of rotation. But, since I don't rotate, I do work really hard in the "off-season" to put organic material and minerals back into the soil to keep it as healthy as possible. I have found that crop rotation is not AS necessary if you garden organically and work continually to put minerals and organic material back into the soil. Y'all, I picked well over 100 tomatoes today....but mostly cherry, grape and currant types. I think I only picked 8 or 10 or 12 "big ones". All those big tomatoes that have been green seemingly forever are starting to break color here, so if it is happening this far south now, then y'all should see it happening to your greenies in the next 10 to 14 days if not sooner. Dawn Here is a link that might be useful: Early Blight and Other Tomato Diseases

I've found that having lots of cherry toms, any cherry toms, will distract me really well from the toms I lack. When you have extremely limited ground room for plants, several cherry varieties (and others!) can grow upward very strongly. That's an awkward sentence but indeterminate plants like that might help when you're cramped for space. Three plants is cramped. if I assume you're talking about ground space, can you maybe also try a few tote bags or five gallon buckets?