Are they in your house or in the garden?..... If they are in your house, step on them, and check your humidity level, they like damp places. If they are in your garden, remove anything that is rotting, old wood, leaves etc. You can't use pesticides because they have a hard exoskeleton. I believe they are related to shrimp, if my high school biology teacher was correct. They really are harmless.
I can almost garauntee you that they are not eating fresh vegetables. It is almost impossible to make a distinction between the bugs killing the plants, and the bugs chowing down on dead plants. There are no chemicals to treat them anyways, they are related to shrimp and are very resilient.
Sow bugs and there other relative the pill bug can only chew soft material, vegetables that are fresh would be impossible for them to bite into. Is it the actual fruit of the vegetable being eaten or the leaves? and you don't say what vegtable is being eaten that alone can determine what insect or bug is eating them. If you want the sow bugs out of your garden, remove all the dead weeds that have been pulled and any other debris that is in it.
I awtch them eat my fresh veg last year. I do not remember clearly which one. I think it was bean. They ate the leaves. My garden is an immaculate.
Unfortunatey if it is the sow bugs that are eating your veg leaves, there is not much you an use, pesticides wouldhurt the beneficial insects and contaminate your veggies, I would let them be. you may need to trim an vegy leaves that are close to the ground so has to keep them away from the bugs. Sometime we have to remenber that the bugs have always been there, we just may never have seen them.