Septoria leaf spot

[Lisa B]

Much less exciting tomato question. My giant, super-producing begemoth now has septoria leaf spot, along with 2 nearby plants. [emoji24][emoji24]

All the websites I've read say the same: no cure. However some say you can slow it by spraying and immediately trimming infected leaves, while my state extension office only says there's no cure and gives prevention instructions.

Anyone have experience? After seeing neigboring, previously spot-free leaves spotted in 24 hours, I'm now taking entire leaf clusters if any leaves on it are spotted at all. But now a full quarter of my plant is down to about a third of its leaves. I can't help but wonder, am I stripping the leaves too early and doing more harm than good?

Should I pull out the diseased plants altogether in an attempt to save my 2 remaining healthy plants? They're all in a roughly 10 x 10 plot and the big infected plant has wines running into the 2 healthy plants, but that side shows no signs of leaf spot yet. Should I just remove the main vines that have some infected leaf clusters to try to save the other half?

Or should I just give up, let it spread and get as many tomatoes as will ripen before all the leaves have shriveled?

 

[dragnlaw]

I'd say you're doing right - but I'm really the last person to give advice. But if it's going to spread then try to get rid of the leaves that you can and give the rest of the leaves and plant a chance.

If it's too much and you're hurting the plant... well, it's going to spread anyhow - treat the symptoms as best you can.

Good luck
and may another more expert come along with a better suggestion!

 

[pepperhead212]

I feel for you, Lisa B. I've had years like that - last year was one of them, when I had record rainfall, until around 7-20, when we went into a drought. If your future forecast is getting dry, you may be able to do something; otherwise, if the wetness keeps up, which I assume you've been getting, to cause this fungus, there's not much you can do.

Last year, when it got dry, I trimmed as much as I could from the plants, then sprayed the remaining parts of the plants with copper soap - something I seldom use (only when absolutely necessary, when it might help,, but it will kill what is on the leaves. Very quickly, the plants grew new growth, and flowered, and I got a generous amount of tomatoes later in the season.

If it is going continue to be rainy there, you can try another application, as long as it won't be getting over 90° for several days after application: an oil and baking soda spray - 1 tb baking soda + 4 tb oil to a gallon of water, plus an emulsifier, like soap or ThermX 70. If you use potassium bicarbonate you can add up to 3 tb. - that's too much sodium, but potassium is a fertilizer! And you can apply some higher amount, without the oil, at higher temps, as long as it's not sunny, as well. I use the potassium bicarbonate (food grade KHCO3 can be bought on Amazon, much cheaper than the gardening brands) as a prophylactic on the tomatoes and cucurbits, though it didn't do anything last season, because it wouldn't stay long! The main thing with any spray is to cover the tops and undersides of the leaves.

Good luck getting this under control!

 

[Lisa B]

Thank you for the advice, Pepperhead! It rained off and on for a few days and that's when all of this started. No rain in the past week, but it was been very humid. I'm hoping I can at least help it limp along until the tomatoes on it ripen. Even with just those I'll have a substantial harvest! Any more would be a great bonus.