Whats wrong with my tomatoe plants?

Question

for 4 years they have not produced well and get leaf damage even though they are healthy to begin with

Answer 1

It sounds like you have caterpillars probably. I cant tell exacttly. Kind of need more specs. But i would say you have a caterpillar or some kind of other insect.

Answer 2

The leaf damage is likely due to insects.  There are organic methods of control that you can use.  

However, the lack of production indicates there could be a problem with the root system of the plants or nutrition.  If you don't mind sacrificing one plant, you could dig out a plant and examine the roots.  Look for misshapen roots perhaps with nodules on them.  If present that could indicate a problem with nematodes, a parasitic round worm that is very small.  Again, there are organic methods to control nematodes.  

Or the soil could be lacking in one or more nutrients or perhaps uneven watering.  To check for soil nutrients, take a sample to a plant nursery or send a sample to an agricultural extension office for analysis of the soil nutrients.  It should be relatively low cost and you should get specific recommendations on what to add to the soil to improve fertility if that is a problem.

Molds that attack tomato plants usually hits the whole plant or large portions of it quite rapidly.

Good luck and good harvesting!