Septoria Experiment

jmsieglaff · June 11, 2020

I came across this powerpoint suggesting a product called MilStop was effective at preventing septoria leaf spot on tomatoes:
https://newenglandvfc.org/sites/newe...TH-organic.pdf

The active ingredient is potassium bicarbonate. I have used the 4 tsp of potassium bicarbonate + a few drops of dish soap in 1 gallon of water as a powdery mildew spray for squash and cucumbers and it was quite effective.

So I decided this year to spray my tomatoes with this to see how it will work. I have always been good about trimming any leaves with even 1 or 2 Septoria spots. I have always been disappointed by how many branches I've had to remove. So this year I'm just removing leaflets with spots instead of the whole leaf with all leaflets--I don't know why I did just do that in the past.

This experiment will be far from scientific--I've sprayed twice so far, both following rainy 2-day periods. I remove any leaflets with spots daily. I have no schedule to spray, just will do it when the weather dictates. A huge factor will be the weather--the last 2-3 years have been very wet, so a drier year should reduce Septoria pressure as well (I'm hoping for drier and it definitely seems like we have fewer rainy days this growing season so far as well as being generally warm, with a few hot days already).

The added benefit of this spray is potassium feeding for tomatoes, via foliar absorption and dripping into the ground.

Fingers crossed! I'd rid the Earth of Septoria even before I'd get rid of mosquitos!

Labradors2 · June 11, 2020

That would be great if it works. I'll stay tuned to hear more

.

My experience with Septoria (which I get every year) is that, if I remove just one infected leaf, the next time I look the whole leaflet is infected and I always think that I should have saved myself the trouble and removed the whole leaflet the first time around. However, if the spray works, perhaps it will prevent that from happening!

Linda

RayR · June 11, 2020

Potassium bicarbonate fungicides are only registered as a control for Powdery Mildews since they are sensitive to low PH. For Septoria it is possibly helpful as a preventative in a limited way. Septoria is such a sinister pathogen, it's difficult to control once infections start and your plants may be infected even though the spots are not yet visible. A Copper soap fungicide has a better chance of killing Septoria once infection sites are visible. I've searched high and low for controls, biological or chemical and there's no silver bullet. Preventative measures are your best shot.

Cole_Robbie · June 11, 2020

I had a market customer once tell me that the healthiest tomato plant he ever grew was underneath the ladder to his pool and got splashed with pool water every day by his grandkids. It was probably the chlorine.

jmsieglaff · June 13, 2020

I've done copper in the past and it is fairly effective, I'm just looking to try things that are not chemical and trying to not use copper if I can. I may also try the bleach spray. I ordered a new sprayer, 2 gallon with a brass tip, I'm excited to see it in action more than the cheap plastic ones I've been using.

edweather · June 13, 2020

The fungal diseases here in south Georgia are brutal. Am going to give a weak bleach spray a try myself. I had to smile at the previous post talking about not using chemicals, but might give bleach a try

jmsieglaff · June 13, 2020

Ha, well good point. I consider bleach spray far less dangerous than commercial fungicides.

June 11, 2020	#1
jmsieglaff Tomatovillian™ Join Date: Jan 2014 Location: Southern WI Posts: 2,742	Septoria Experiment I came across this powerpoint suggesting a product called MilStop was effective at preventing septoria leaf spot on tomatoes: https://newenglandvfc.org/sites/newe...TH-organic.pdf The active ingredient is potassium bicarbonate. I have used the 4 tsp of potassium bicarbonate + a few drops of dish soap in 1 gallon of water as a powdery mildew spray for squash and cucumbers and it was quite effective. So I decided this year to spray my tomatoes with this to see how it will work. I have always been good about trimming any leaves with even 1 or 2 Septoria spots. I have always been disappointed by how many branches I've had to remove. So this year I'm just removing leaflets with spots instead of the whole leaf with all leaflets--I don't know why I did just do that in the past. This experiment will be far from scientific--I've sprayed twice so far, both following rainy 2-day periods. I remove any leaflets with spots daily. I have no schedule to spray, just will do it when the weather dictates. A huge factor will be the weather--the last 2-3 years have been very wet, so a drier year should reduce Septoria pressure as well (I'm hoping for drier and it definitely seems like we have fewer rainy days this growing season so far as well as being generally warm, with a few hot days already). The added benefit of this spray is potassium feeding for tomatoes, via foliar absorption and dripping into the ground. Fingers crossed! I'd rid the Earth of Septoria even before I'd get rid of mosquitos!

June 11, 2020	#2
Labradors2 Tomatovillian™ Join Date: Jul 2013 Location: Ontario Posts: 3,897	That would be great if it works. I'll stay tuned to hear more . My experience with Septoria (which I get every year) is that, if I remove just one infected leaf, the next time I look the whole leaflet is infected and I always think that I should have saved myself the trouble and removed the whole leaflet the first time around. However, if the spray works, perhaps it will prevent that from happening! Linda Last edited by Labradors2; June 11, 2020 at 03:56 PM.

June 13, 2020	#6
edweather Tomatovillian™ Join Date: Jul 2012 Location: Southeast GA, USDA 9a, HZ9, Sunset Z28 Posts: 396	The fungal diseases here in south Georgia are brutal. Am going to give a weak bleach spray a try myself. I had to smile at the previous post talking about not using chemicals, but might give bleach a try __________________ You'll be surprised what you'll never have to do, if you put it off long enough.

June 11, 2020	#3
RayR Tomatovillian™ Join Date: Jun 2010 Location: Cheektowaga, NY Posts: 2,466	Potassium bicarbonate fungicides are only registered as a control for Powdery Mildews since they are sensitive to low PH. For Septoria it is possibly helpful as a preventative in a limited way. Septoria is such a sinister pathogen, it's difficult to control once infections start and your plants may be infected even though the spots are not yet visible. A Copper soap fungicide has a better chance of killing Septoria once infection sites are visible. I've searched high and low for controls, biological or chemical and there's no silver bullet. Preventative measures are your best shot.

June 11, 2020	#4
Cole_Robbie Tomatovillian™ Join Date: Jun 2012 Location: Illinois, zone 6 Posts: 8,407	I had a market customer once tell me that the healthiest tomato plant he ever grew was underneath the ladder to his pool and got splashed with pool water every day by his grandkids. It was probably the chlorine.