Hydrogen Peroxide for Early blight, etc

Dewayne mater · June 26, 2014

Has anyone successfully used hydrogen peroxide for control of early blight and/or other disease? A local N. Tx gardening personality, Howard Garrett, A/k/a the dirt doctor says he does. He is very big on natural solutions and chemical avoidance and I think sometimes his claims are based on his anecdotal experiences vs. studies, but, when you are using less toxic materials, it seems worth a shot with or without studies. Here is what he recently said in a newsletter and I wonder if any of you have successfully used it:

"I have used hydrogen peroxide as part of Sick Tree Treatment to cure Rose Rosette on Knockout roses and various diseases like powdery mildew on crape myrtles and early blight on tomatoes[...stuff about using it to control mustard algae in a pool...]

You can also use the grocery or drug store 3% stuff for treatment of Rose Rosette, powdery mildew, fire blight, curly top and other plant pathogens. If you chose the 3% product, use about 2 parts water and 1 part hydrogen peroxide in the mix. Or better still, for plant diseases, add it to Garrett Juice instead of using just water. Adding about 16 oz. of 3% hydrogen peroxide to 1 gallon of Garrett Juice (ready-to-spray mix) seems to work very well for controlling various plant diseases. Spraying straight 3% product will burn plants in hot weather and is a waste of money.

Whether using concentrated 33% product or grocery store 3% product, the spray coming out of the sprayer should be about 1% hydrogen peroxide or slightly less. It is amazing how well it works and there is no need for the toxic chemicals. Hydrogen peroxide is a chemical but just one atom different than water (H2O2 vs H2O) and degrades very quickly to water and oxygen. It will even happen in the containers after being exposed to air, so always use fresh material – even for those personal cuts and scrapes."

I know some of you use Garrett juice and I have as well. This is not an effort to push any product. However, if there are ways to control disease that are less toxic, then I'm interested. Feedback appreciated.

Dewayne Mater

RayR · June 26, 2014

I haven't used H2O2 myself for EB or other foliar fungal pathogens but there is scientific evidence that it is effective at killing fungal spores. Plants can even produce H2O2 themselves in response to attack. I know some people here use it in seed starting to ward off damping off. There is some evidence that supports that. This Eqyptian study even showed that seeds treated in H2O2 somehow acquired induced resistance to Rhizoctonia solani and Fusarium oxysporum.

H2O2 is more likely to kill fungal spores than bacteria, it is actually a poor bactericide, at best it will inhibit growth for a short while. It's worth a shot to see if it has any effectiveness on Early Blight or other foliar pathogens. At 1% concentration its not likely to have any ill effects on beneficial bacteria on the leaf surface. It's no silver bullet but it would be interesting to see proof that it does help.

Dewayne mater · June 27, 2014

Interesting study thanks! Might we worth giving tomato seeds and overnight bath in H2O2 before germination.

Seems worth a shot as a foliar too, given the possibility of it being helpful and no apparent downside.

D.M.

Eric02476 · July 3, 2014

As it happens, I today received my order of BioSafe Disease Control to try to get a better handle on some sort of foliar blight or mildew that's getting ahead of me in one of my tomato beds, despite heavy use of Serenade, Actinovate and aggressive pruning of infected foliage.

The product is 5.34 % Hydrogen Peroxide and 1.36% Peroxyacetic Acid. It used to be named Oxidate RTU and it is a much more dilute version of Oxidate 2.0 for homeowner use (the latter product, at about 27% concentration is intended for commercial use). It's OMRI listed so approved for organic gardening, but does come with a healthy warning about wearing eye protection, which I fully intend to heed.

I'll post here about how well it works for this situation. It's labeled for a range of fungal foliar diseases, although far fewer than Oxidate 2.0 (then again, I'd really rather not wear hazmat protection when mixing the latter).

BTW I'm not 100% certain which disease I'm dealing with but it is seems fungal vs. bacterial, from my prior experience with a range of diseases. Blotches of yellow on the leaves starting from the lower leaves and spreading up. Maybe a persistent case of powdery mildew, maybe early blight that I haven't given enough time to fully manifest, something else, not sure... I tend to prune before waiting to see how the lesions evolve

greentiger87 · July 3, 2014

It works about as well as bleach, and burns less. Like bleach, it requires very frequent spraying. It's essentially a surface disinfectant.

To create homemade equivalent of Oxidate, just add distilled vinegar to hydrogen peroxide. You can only do this just before spraying - add both into an almost filled spray bottle or tank. I used about a 1/2 cup vinegar per gallon. The two will react to form peroxyacetic acid, which is a much stronger disinfectant than peroxide alone. However, it also decomposes in a dilute solution very fast, so only mix right before.

I'll hold my tongue about Howard Garrett because it might break Tomatoville rules.

Eric02476 · July 3, 2014

Ray, I know you use Actinovate quite a lot. From your knowledge of how that organism works, would you expect that H202 would kill it off? That might give me pause for using the stuff, as I've invested a few sprays of Actinovate + Serenade.

However, if I get freakin' Septoria again this year I will not hesitate to try the oxidation approach from the get-go. Last year was a disaster and it laughed at my careful preventive treatments. Evil, evil, evil.

JamesL · July 3, 2014

Greentiger and Ray R, I seem to recall talking about Oxidate and h2o2 with both of you a few years back. I can't find the thread reference though.

Dewayne,
I have experimented with h2o2 quite extensively the last few years. It is effective for fungal diseases. It is not the end all, be all, obviously or everyone would use it. it does have a place in the arsenal though.

Partial to the food grade( FG) version - 35%

Do NOT get it on you! And it is flammable…..

In comparing it to the store bought 3% version (after dilution) the FG version was the winner.

h2o2 starts to oxidate easily with exposure to heat, light, air, etc. so I was making the assumption that my bottles of store bought 3% were already somewhat degraded.
The problem of course is that you cannot assume that will always be the case so when you dilute it for use it could be weaker than anticipated.

Seed starting - I did not find it to be effective. In fact I had poorer germination no matter what percentage I used.
This paper isn't on point but it makes the same comment about h2o2 and germination.
http://ijappjournal.com/wp-content/u...00-704.doc.pdf

Works very well for damping off though.(depending on where you live)

My best garden use – A spot spray at 1% mix. I have used as high as 3% as a spot spray and I have tested it as high as 6%. I have seen it leave white spots on healthy leaves, depending on the plant, and on tomatoes at mixes higher than 1%. 1% is effective though, so I generally keep to that percentage.

Greentiger,
How much h202 are you mixing with the vinegar per gallon?

Eric,
I don’t think we ever got an actual report back from anyone using the Oxidate product, so would love to hear how it goes for you.

Howard Garrett – just took a spin through his website. I think I will take Greentiger’s lead and hold my tongue as well…..

RayR · July 3, 2014

I remember this discussion from a couple years ago, I don't know if anyone got an answer about using Oxidate and it's effect on beneficial biologicals.
http://www.tomatoville.com/showthread.php?t=24494

I suppose if you are going to use BioSafe, you would apply that first. Since it isn't a persistent disinfectant, you could then wait a little while and then apply Actinovate and Serenade. Then see if the Septoria is under control for awhile.
I never expect a pathogen like Septoria or Early Blight to be completely defeated in my garden, if I can keep it controlled as a minor nuisance instead of a raging defoliating monster, that's a realistic result. I have Septoria in my garden now on some plants, so I'm back out there pruning the lower stems that are infected and applying Actinovate. I've only sprayed once this season so I'll be steeping up spraying regularly now. Some varieties are definitely more susceptible to infection than others from what I see. Giant Red Pear and Sungold have it and most other varieties aren't showing much of anything yet. Same thing happened last year.

Eric02476 · July 5, 2014

Well, after 24 hours of heavy rain, the disease in these beds is -- unsurpisingly -- making a comeback, despite active pruning and the serenade & actinovate applications prior, so I will try the BioSafe (nee Oxidate) product tonight and report back in a couple of days. Like Ray, I consider it a success if I can just slow it down; eradication is of course unrealistic at this stage.

Ray, I like the idea of your sequence with this and the biologicals. If this helps more than the biologicals alone, I'll try that rotation.

It would obviously be more helpful to everyone if I know for sure what I'm dealing with, so I snapped some photos and I think I will post them in a new thread to seek some ID help. I seem to have 2 things happening, one on each variety of cherry tomato in the bed. One issue looks sort of like early blight minus the clear concentric ring pattern; the other possibly bacterial canker, but really not sure.

UPDATE: consensus on my ID thread so far is gray mold on one variety, and early blight on the other. Early last evening I gave them all a very heavy spray of the BioSafe preparation at the 0.85 fluid ounce/gallon concentration per the label for initial application. The product itself 5.34 % Hydrogen Peroxide and 1.36% Peroxyacetic Acid. I am too lazy to do the math on the resultant concentration

This morning, there are no signs of burn, anyway. I'll re-apply in a few days per the label. The weather this week is expected to be about the same as last week - mostly dry with a day of rain and moderate humidity. I'll see how the week goes for the spread of both diseases and post as to whether it moved any slower this week.

Eric

greentiger87 · July 9, 2014

James - I use enough hydrogen peroxide to bring it near 1% concentration, which is a little over 1 liter per gallon.

I talked to an organic chemistry professor and an expert on hospital disinfection about this. The prof confirmed my model of in situ production of peroxyacetic acid/Peracetic acid, subject to an equilibrium, of course. He said that it's often made this way when peracetic acid is used in organic synthesis of diols from alkenes. The disinfection expert explained the weird property of organic peroxides, that within a surprisingly large range, their disinfection power remains relatively constant because of the equilibrium constantly replenishing the supply of the highly reactive active species. It's now state of the art to use mixtures of organic acids and hydrogen peroxide as disinfectants - it's cheap, really effective, relatively non-toxic, and robust to organic contamination.

Sorry for the spiel, I just find this stuff fascinating.

JamesL · July 10, 2014

GT,
That was good info thanks for sharing it.

Keiththibodeaux · July 11, 2014

Try some Chamomile Tea. Work great for damping off, so maybe. Cheap to try. Worst case, good tea to ease your mind.

Eric02476 · July 20, 2014

I'm finally reporting back as promised above. Over the past couple of weeks we had several days of storms, humidity and heavy rains -- sure to cause high disease pressure, and it did.

I kept up with the BioSafe applications to the affected tomatoes. I applied it at the label-recommended rate of 0.85 fluid ounce (about 5 tsp.) per gallon for high disease pressure conditions. I stopped using Actinovate and Serenade during this time.

So far I'm reasonably happy with the results. The stuff certainly doesn't eradicate the diseases (nothing will, really) and I have to keep up with pruning off infected leaves etc and repspraying every 2 or 3 days. But so far the plants are still doing OK despite the horrid weather. So, the spray seems to be helping to slow down the diseases at least as well as my usual regimen of Actinovate/Serenade and sometimes Neem.

Since I didn't do any sort of comparison or control, I have no way of telling what would have happened with no treatment or treatment with other agents, but as least the plants are still alive and growing - compared to many other years with this kind of weather, when I haven't been so lucky.

If anyone tries the BioSafe product, do heed the warning about eye protection. I wear it when spraying. This consumer version of the Oxidate product is far less concentrated than the commercial one, but you still really don't want the spray in your eyes.

Eric

JamesL · July 21, 2014

Eric,
Good follow up report. Thanks for sharing!

Cole_Robbie · July 21, 2014

I met a guy a few weeks ago who told me that the best tomato plants he ever grew were next to his swimming pool and got splashed with pool water by his grandkids all summer. He thought it would hurt them, but they did very well. I wonder if it was the chlorine in the pool water killing fungal spores like blight.

June 26, 2014	#1
Dewayne mater Tomatovillian™ Join Date: May 2008 Location: DFW, Texas Posts: 1,212	Hydrogen Peroxide for Early blight, etc Has anyone successfully used hydrogen peroxide for control of early blight and/or other disease? A local N. Tx gardening personality, Howard Garrett, A/k/a the dirt doctor says he does. He is very big on natural solutions and chemical avoidance and I think sometimes his claims are based on his anecdotal experiences vs. studies, but, when you are using less toxic materials, it seems worth a shot with or without studies. Here is what he recently said in a newsletter and I wonder if any of you have successfully used it: "I have used hydrogen peroxide as part of Sick Tree Treatment to cure Rose Rosette on Knockout roses and various diseases like powdery mildew on crape myrtles and early blight on tomatoes[...stuff about using it to control mustard algae in a pool...] You can also use the grocery or drug store 3% stuff for treatment of Rose Rosette, powdery mildew, fire blight, curly top and other plant pathogens. If you chose the 3% product, use about 2 parts water and 1 part hydrogen peroxide in the mix. Or better still, for plant diseases, add it to Garrett Juice instead of using just water. Adding about 16 oz. of 3% hydrogen peroxide to 1 gallon of Garrett Juice (ready-to-spray mix) seems to work very well for controlling various plant diseases. Spraying straight 3% product will burn plants in hot weather and is a waste of money. Whether using concentrated 33% product or grocery store 3% product, the spray coming out of the sprayer should be about 1% hydrogen peroxide or slightly less. It is amazing how well it works and there is no need for the toxic chemicals. Hydrogen peroxide is a chemical but just one atom different than water (H2O2 vs H2O) and degrades very quickly to water and oxygen. It will even happen in the containers after being exposed to air, so always use fresh material – even for those personal cuts and scrapes." I know some of you use Garrett juice and I have as well. This is not an effort to push any product. However, if there are ways to control disease that are less toxic, then I'm interested. Feedback appreciated. Dewayne Mater

July 3, 2014	#4
Eric02476 Tomatovillian™ Join Date: Jun 2008 Location: Eastern Massachusetts, Zone 6a Posts: 50	As it happens, I today received my order of BioSafe Disease Control to try to get a better handle on some sort of foliar blight or mildew that's getting ahead of me in one of my tomato beds, despite heavy use of Serenade, Actinovate and aggressive pruning of infected foliage. The product is 5.34 % Hydrogen Peroxide and 1.36% Peroxyacetic Acid. It used to be named Oxidate RTU and it is a much more dilute version of Oxidate 2.0 for homeowner use (the latter product, at about 27% concentration is intended for commercial use). It's OMRI listed so approved for organic gardening, but does come with a healthy warning about wearing eye protection, which I fully intend to heed. I'll post here about how well it works for this situation. It's labeled for a range of fungal foliar diseases, although far fewer than Oxidate 2.0 (then again, I'd really rather not wear hazmat protection when mixing the latter). BTW I'm not 100% certain which disease I'm dealing with but it is seems fungal vs. bacterial, from my prior experience with a range of diseases. Blotches of yellow on the leaves starting from the lower leaves and spreading up. Maybe a persistent case of powdery mildew, maybe early blight that I haven't given enough time to fully manifest, something else, not sure... I tend to prune before waiting to see how the lesions evolve Last edited by Eric02476; July 3, 2014 at 04:50 PM.

July 3, 2014	#7
JamesL Tomatovillian™ Join Date: Nov 2011 Location: Long Island NY Posts: 1,992	Greentiger and Ray R, I seem to recall talking about Oxidate and h2o2 with both of you a few years back. I can't find the thread reference though. Dewayne, I have experimented with h2o2 quite extensively the last few years. It is effective for fungal diseases. It is not the end all, be all, obviously or everyone would use it. it does have a place in the arsenal though. Partial to the food grade( FG) version - 35% Do NOT get it on you! And it is flammable….. In comparing it to the store bought 3% version (after dilution) the FG version was the winner. h2o2 starts to oxidate easily with exposure to heat, light, air, etc. so I was making the assumption that my bottles of store bought 3% were already somewhat degraded. The problem of course is that you cannot assume that will always be the case so when you dilute it for use it could be weaker than anticipated. Seed starting - I did not find it to be effective. In fact I had poorer germination no matter what percentage I used. This paper isn't on point but it makes the same comment about h2o2 and germination. http://ijappjournal.com/wp-content/u...00-704.doc.pdf Works very well for damping off though.(depending on where you live) My best garden use – A spot spray at 1% mix. I have used as high as 3% as a spot spray and I have tested it as high as 6%. I have seen it leave white spots on healthy leaves, depending on the plant, and on tomatoes at mixes higher than 1%. 1% is effective though, so I generally keep to that percentage. Greentiger, How much h202 are you mixing with the vinegar per gallon? Eric, I don’t think we ever got an actual report back from anyone using the Oxidate product, so would love to hear how it goes for you. Howard Garrett – just took a spin through his website. I think I will take Greentiger’s lead and hold my tongue as well….. Last edited by JamesL; July 3, 2014 at 07:02 PM.

July 5, 2014	#9
Eric02476 Tomatovillian™ Join Date: Jun 2008 Location: Eastern Massachusetts, Zone 6a Posts: 50	Well, after 24 hours of heavy rain, the disease in these beds is -- unsurpisingly -- making a comeback, despite active pruning and the serenade & actinovate applications prior, so I will try the BioSafe (nee Oxidate) product tonight and report back in a couple of days. Like Ray, I consider it a success if I can just slow it down; eradication is of course unrealistic at this stage. Ray, I like the idea of your sequence with this and the biologicals. If this helps more than the biologicals alone, I'll try that rotation. It would obviously be more helpful to everyone if I know for sure what I'm dealing with, so I snapped some photos and I think I will post them in a new thread to seek some ID help. I seem to have 2 things happening, one on each variety of cherry tomato in the bed. One issue looks sort of like early blight minus the clear concentric ring pattern; the other possibly bacterial canker, but really not sure. UPDATE: consensus on my ID thread so far is gray mold on one variety, and early blight on the other. Early last evening I gave them all a very heavy spray of the BioSafe preparation at the 0.85 fluid ounce/gallon concentration per the label for initial application. The product itself 5.34 % Hydrogen Peroxide and 1.36% Peroxyacetic Acid. I am too lazy to do the math on the resultant concentration This morning, there are no signs of burn, anyway. I'll re-apply in a few days per the label. The weather this week is expected to be about the same as last week - mostly dry with a day of rain and moderate humidity. I'll see how the week goes for the spread of both diseases and post as to whether it moved any slower this week. Eric Last edited by Eric02476; July 6, 2014 at 11:50 AM.

June 26, 2014	#2
RayR Tomatovillian™ Join Date: Jun 2010 Location: Cheektowaga, NY Posts: 2,466	I haven't used H2O2 myself for EB or other foliar fungal pathogens but there is scientific evidence that it is effective at killing fungal spores. Plants can even produce H2O2 themselves in response to attack. I know some people here use it in seed starting to ward off damping off. There is some evidence that supports that. This Eqyptian study even showed that seeds treated in H2O2 somehow acquired induced resistance to Rhizoctonia solani and Fusarium oxysporum. H2O2 is more likely to kill fungal spores than bacteria, it is actually a poor bactericide, at best it will inhibit growth for a short while. It's worth a shot to see if it has any effectiveness on Early Blight or other foliar pathogens. At 1% concentration its not likely to have any ill effects on beneficial bacteria on the leaf surface. It's no silver bullet but it would be interesting to see proof that it does help.

June 27, 2014	#3
Dewayne mater Tomatovillian™ Join Date: May 2008 Location: DFW, Texas Posts: 1,212	Interesting study thanks! Might we worth giving tomato seeds and overnight bath in H2O2 before germination. Seems worth a shot as a foliar too, given the possibility of it being helpful and no apparent downside. D.M.

July 3, 2014	#5
greentiger87 Tomatovillian™ Join Date: Aug 2012 Location: Houston, TX - 9a Posts: 211	It works about as well as bleach, and burns less. Like bleach, it requires very frequent spraying. It's essentially a surface disinfectant. To create homemade equivalent of Oxidate, just add distilled vinegar to hydrogen peroxide. You can only do this just before spraying - add both into an almost filled spray bottle or tank. I used about a 1/2 cup vinegar per gallon. The two will react to form peroxyacetic acid, which is a much stronger disinfectant than peroxide alone. However, it also decomposes in a dilute solution very fast, so only mix right before. I'll hold my tongue about Howard Garrett because it might break Tomatoville rules.

July 9, 2014	#10
greentiger87 Tomatovillian™ Join Date: Aug 2012 Location: Houston, TX - 9a Posts: 211	James - I use enough hydrogen peroxide to bring it near 1% concentration, which is a little over 1 liter per gallon. I talked to an organic chemistry professor and an expert on hospital disinfection about this. The prof confirmed my model of in situ production of peroxyacetic acid/Peracetic acid, subject to an equilibrium, of course. He said that it's often made this way when peracetic acid is used in organic synthesis of diols from alkenes. The disinfection expert explained the weird property of organic peroxides, that within a surprisingly large range, their disinfection power remains relatively constant because of the equilibrium constantly replenishing the supply of the highly reactive active species. It's now state of the art to use mixtures of organic acids and hydrogen peroxide as disinfectants - it's cheap, really effective, relatively non-toxic, and robust to organic contamination. Sorry for the spiel, I just find this stuff fascinating.

July 10, 2014	#11
JamesL Tomatovillian™ Join Date: Nov 2011 Location: Long Island NY Posts: 1,992	GT, That was good info thanks for sharing it.

July 11, 2014	#12
Keiththibodeaux Tomatovillian™ Join Date: Jun 2011 Location: Louisiana Posts: 587	Try some Chamomile Tea. Work great for damping off, so maybe. Cheap to try. Worst case, good tea to ease your mind.

July 20, 2014	#13
Eric02476 Tomatovillian™ Join Date: Jun 2008 Location: Eastern Massachusetts, Zone 6a Posts: 50	I'm finally reporting back as promised above. Over the past couple of weeks we had several days of storms, humidity and heavy rains -- sure to cause high disease pressure, and it did. I kept up with the BioSafe applications to the affected tomatoes. I applied it at the label-recommended rate of 0.85 fluid ounce (about 5 tsp.) per gallon for high disease pressure conditions. I stopped using Actinovate and Serenade during this time. So far I'm reasonably happy with the results. The stuff certainly doesn't eradicate the diseases (nothing will, really) and I have to keep up with pruning off infected leaves etc and repspraying every 2 or 3 days. But so far the plants are still doing OK despite the horrid weather. So, the spray seems to be helping to slow down the diseases at least as well as my usual regimen of Actinovate/Serenade and sometimes Neem. Since I didn't do any sort of comparison or control, I have no way of telling what would have happened with no treatment or treatment with other agents, but as least the plants are still alive and growing - compared to many other years with this kind of weather, when I haven't been so lucky. If anyone tries the BioSafe product, do heed the warning about eye protection. I wear it when spraying. This consumer version of the Oxidate product is far less concentrated than the commercial one, but you still really don't want the spray in your eyes. Eric

July 21, 2014	#14
JamesL Tomatovillian™ Join Date: Nov 2011 Location: Long Island NY Posts: 1,992	Eric, Good follow up report. Thanks for sharing!

July 21, 2014	#15
Cole_Robbie Tomatovillian™ Join Date: Jun 2012 Location: Illinois, zone 6 Posts: 8,407	I met a guy a few weeks ago who told me that the best tomato plants he ever grew were next to his swimming pool and got splashed with pool water by his grandkids all summer. He thought it would hurt them, but they did very well. I wonder if it was the chlorine in the pool water killing fungal spores like blight.