If you could provide a pic of your plants it would help

Here is a link that might be useful: Try comparing here Cornwell

So, back to my odd question. I am so determined to be able to diagnose my tomato diseases, that I am wondering if it is possible to diagnose; virus from bacteria from fungi by using a common microscope etc...

*****

No, you can't use a common microscope to differentiate between viruses and fungi and bacteria and nematodes that are known to cause tomato diseases.

Have you looked in the Pest and Disease Forum here, link at the top of this first page? There's a Problem Solver there and I'd use either that TAMU one or Cornell one, and look at the pictures b'c tomato diseases need to be IDed by plant and fruit symptoms. it's often difficult to ID diseases with pictures b'c pictures are static while disease is progressive, but most of the common foliage diseases are not hard to diagnose.

If all got "Sick" at the same time, I doubt it was a mineral deficiency, rather, probably a wind or rain borne foliage disease. In new groud I don't think you'd have any soilborne tomato diseases and even if some of your nursery plants imported something it could NOT allow for ALL of the plants to die in the same season.

You don't say where you live and garden, in a general sense, and that's important since tomato diseases are regionalized, some being present in some areas and not others.

Carolyn

Sometimes the problem is not disease, but instead yourself or a neighbor (and the neighbor does not have to be directly next door) having one of those yard services spray to kill off the weeds and dandylines. The stuff is lethal on tomatoes!

If the wind wafts it into your garden it's all over. I have not had this happen but one of my good friends did.

I am not convinced that being able to diagnose the specific disease is that important. There are many possible tomato diseases, but only a few ways to treat them. The most important thing is to try to prevent them in the first place. You do that by first ensuring that your soil is appropriate for tomatoes: with good fertility, the right pH, good drainage and weed free. Next you need to use a fungicide soon after planting out to protect against the rain and airborne fungi that are the maincause of disease. Many people use Daconil. If you prefer organic methods, neem oil offers some protection against fungus and also kills most of the insects that attack tomatoes. They are another source of disease. If you are vigilant about preventing fungal and insect attacks and treating them if they occur anyway, you can minimize the damage.