The reason I asked if there were divots on the leaf, is because there is a similar type of appearance to leaves worked upon by the four lined plant bug. I grew mums commercially for many years and one year had a good deal of damage to the crop, seemingly overnight, on a few benches, having never seen the insects on the plants I scouted regularly. The plant inspector was shown the material (entymologist) and identified it as four line plant bug aftermath. Sure enough, after scouting the crop, I found them. I am seeing them this year in my vegetable garden and suspect the pressure is high this year. I'm not saying your crop doesn't reflect ozone damage, but I've heard that diagnosis applied to plants before by experts and had it not be so. Is there a manufacturing facility nearby? I was a grower for a nursery once and pinpointed some foliar damage by industrial fumes on a particularly susceptible line of plants.

Doesn't look like disease. More like an environmental glitch.

Septoria can survive on living tissue and plant debris but the odds of survival on metal is slim to none and it cannot create spores below 50 degrees so winter survival would be very limited if any. And since it is air borne any subsequent infections are likely from the air not the cages. But if you want to clean your cages then the standard cleaning solution recommended for disinfecting pots, trays, and other garden equipment is a 1:10bleach solution - 1 part bleach in 10 parts water. Dave

In your zone (which is also my zone), Mother's Day should normally be more than fine for planting out. But both last year and this year, we had a very wet, cool May. Last year some of my plants also got speck very early, during May. Replacement plants, however, that were very small and young when they went into the ground, caught up to the older plants easily after a few weeks and went on to produce just as much. Those didn't go in until after the first week of June. Of course, we also had warm weather until late into fall, with a killing frost not hitting until November. This year, I'm deliberately planting late. I have some tomatoes planted out, but not all yet. The Drowns who run Sandhill Preservation in zone 5 IA say they now start their tomatoes in mid-May and put them out in mid-June (!!!) because they see less disease, and they still get plenty of tomatoes. I'm a little too impatient to get tomatoes to wait quite that long, and we're a bit warmer here, but around the Philadelphia area, older gardeners still say Memorial Day is when you plant out tomatoes. The race to boast the earliest tomatoes may not be worth it here (well, not yet), since we're still not racing extreme heat and pests the way more southern gardeners are, and we do have a rather long growing season, unlike more northern gardeners. Anyway, the short version is: I don't think you need to wait longer, but if you do, you'll have to spray your plants frequently during May if we get a lot of rain again. Or you can wait and set them out later. But if you go that route, prepared to be constantly tortured as others post beautiful photos of lush tomato plants they put in the ground early, LOL.