its blurry, but the main lesions in the picture aeem too large for septoria. Remember one can have more than one disease at a given time. It's not all that uncommon to see septoria and early blight on the same plant.

My vote goes for early blight, but they can both be treated the same way.

Remove infected leaves and dispose of them in the garbage. Blight will overwinter on infected plant parts that remain in or on the ground, and will recur yearly, so the removed parts must be quarantined and disposed of remotely. They shouldn't go into the compost pile for this reason also.

Once the infected leaves are removed, start a fungicide treatment. I've used Sulphur spray with good results, but most organic gardeners swear by Copper based sprays. Daconil is always an option, but a last resort for me.

An ounce of prevention is worth a pound of cure though, and a weekly neem oil regiment has prevented the blight from taking my tomatoes so far this year. Neem oil wont kill the blight, but it will hinder it's ability to set in the first place.

I've included a link to a good article that should help.

Happy Gardening,

Michael

Here is a link that might be useful: Tomato diseases and treatments

I agree with the others... the central leaf in the photo seems to show symptoms of Early Blight, but it is possible it has both Septoria and Early Blight.

Dang! Ok. It's got my Park's Whopper, Better boy and Best Boys. None of which of course have EB resistance.

Is the source on the leaves or does live in the plant? In other words if I chop a limb off is the plant still infected?

It's a foliar fungal infection. It isn't systemic. The spores are around in the soil and probably on the plant even in places where it isn't showing infection, but removing the infected foliage will help.

Septoria and Early blight have the same treatment, so figuring out which one it is isn't too important.

I'm not saying this is what happened but is it possible these plants came from the nursery with blight already on them?

I do cleanup my garden each year and have kept the ground heavily mulched with grass clippings. And I drip irrigate. I do realize it could live in the soil for years however.

I just find it strange that I bought six from the store(Ace Hardware actually) and they all have apparently early blight. I have 10 more all heirloom with no disease resistance that we grew from seed that do not have this.
Or very little sign of it.

is it possible these plants came from the nursery with blight already on them?

Slim to none. They have spent most of their life inside in conditions unfavorable to fungus problems.

The fungus is airborne as well as in the soil. If it exists anywhere within 5 miles you can get it, same as all of us, when the conditions for fungus growth are favorable. No comfort I know but it is a fact of tomato growing. That is one reason why several of us started preaching 3 months back that fungicide use would be and should be heavy this year because the spring weather in much of the country was fungus-favorable.

So to avoid it in chronic areas you use a fungicide from the day of plant out or you learn to live with it.

Dave

Ok check out the carnage in the row. Which I tosses out after this photo.

Thanks, Dave. That sums it up pretty good. Had no idea it could spread so easily My experience this year with aerated compost tea is it didn't do squat to slow it down once the rain started.

Have done a little research and found a couple of university links on aerated compost tea and they kind of confirm those results too with aerated tea.

Trying this year to be 100% organic so for now, we'll live with it. But I don't like it.

If you want to stay organic there are organic fungicides available. Not as effective IME but better than doing nothing.

As to the "carnage", I've seen worse if that is any comfort. All in all the plants look pretty good. Personally I prefer much heavier mulching than in your pics but that's just me.

{{gwi:17830}}

Dave