I think people didn't respond to your post below was because:

1. It is fathers day so a lot of people are celebrating that.

2 there is no silver bullet that is going to cure aphids, disease, hornworms.

There are things you can do to try to remedy the issues you named but they vary greatly from the truly organic (like picking off horn worms individually) to a more aggressive approach (nuke the plant with a bunch of chemicals).

Also most people diagnose what the problem is first before trying to figure out a remedy.
To really answer your very vague question properly someone would have to write a book of FAQ on tomato disease and problems.

Luckily someone did in the FAQ section. You may want to read it as it probably will answer your questions.

I wish I could link it but can't do on my crackberry.

Try some Ortho unless you're organic. I don't know much about organic gardening but I know you can pluck the worms off and maybe use some Neem oil.

Can't say I've ever seen aphids on my tomatoes. Hornworms are easy enough to pick off. Preventing diseases of tomatoes is very hard. You have to figure out what the disease is before you can take any corrective action. If you post a picture of the leaves, we'll try to help you figure out the disease.

react to me !

Ok.

Aphids can't be "prevented" except avoiding excess nitrogen fertilizer helps as it is attractive to them. They can be treated in many ways - just hosing them off with water is what I do. May not get them all but makes a big difference. Otherwise just browse through all these previous discussions on aphids for all kinds of info on them.

Disease - it all depends on what the disease is. Different treatments for different diseases. The link below can help you determine which of the many common ones you might have and offers treatment help.

Hornworms - as already mentioned, just picking them off works for most of us but you can also search 'hornworms' for lots of discussions about Bt and other forms of control.

Dave

Here is a link that might be useful: TAMU - Common Diseases of Tomato Photos

I like IPM for solving problems with pests. With foliage problems I use an organic spray.

Here is a link that might be useful: IPM

Disease: Strongly depends on the disease.

Aphids: You can hose them off, but you need to be thorough. Not using any broad-spectrum pesticides (neem included!) will help you build up predator populations. Controlling ants (if present) will stop them from guarding the aphids. Insecticidal soaps and horticultural oils are a fairly narrow-spectrum approach to controlling aphids (they only kill soft-bodied insects).

Hornworms: Hand-picking, if you're up to it, obviously works. BTk (Bacillus thuringiensis var Kurstaki) works well and is incredibly narrow spectrum, but you need to apply it early and often. I would avoid broad spectrums if possible, especially while the tomatoes are flowering, or you might kill your pollinators. If you do use a broad spectrum, use one with a low avian toxicity (like neem), since birds are a natural control of caterpillars.

thanks for the help. i do have quite a bad ant problem any suggestions?

As explained on one of your other posts on ants (linked below), they are seldom a serious problem in the home garden (except for fire ants) and are usually there because you have an aphid problem.

Tips for controls are offered in your other thread.

Dave

Here is a link that might be useful: Your post on ants

Rotating crops is an important measure to reduce disease and insects.

Turning the soil in your garden each Fall and Spring really discourages ants too.

But I don't have anything against ants.

1. They really do turn up the soil pretty good.
2. They are really hard on some annoying insects.
3. I don't have many aphids because the ladybugs love my organic yard so the ants aren't protecting them.
4. A smear of tanglefoot keeps them off the hummingbird feeder wires without hurtng them.
5. They never come in my house.
6. There are no fire ants here (yet).
7. They are admirably industrious.

try spinosad pesticide kills chewing and sucking insects and is organic.