Safe, organic treatment for Septoria?

nygardener(z6 New York)August 1, 2010

My tomato plants have Septoria leaf spot. Removing the affected leaves by itself doesn't seem to be halting its spread, even though the weather has been warm and dry. I'm very reluctant to spray with a chemical or copper-based fungicide, but am open to remedies such as a baking soda spray, etc. Or I could continue removing spotted leaves, harvest what I can before the plants are defoliated (and hope the fungus slows down by itself). I'm also considering rotating out of tomatoes (i.e. not growing them) for a year or two to try to rid my soil of the spores. Can anyone offer advice?

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korney19(z6a Buffalo, NY)

Copper is considered organic in many forms/formulas and some versions are OMRI approved. Cheap stuff is available on places like ebay but the best stuff contains 53% copper, or more.

Basic Copper 53 (EPA 45002-8) OMRI, REI 24 hrs (basic copper sulfate, 53% metallic equiv. Group M1) (Albaugh); T Anth, Bac Spot and Speck, Canker, EB, LB, Gray Leaf mold, Septoria, 2-4 lb/A; E Alter Blt, Anth, Phomopsis, DM, Leaf spots, 3-4 lb; P Anth, Bac spot, DM, 3-4 lb. 0 DTH.

Above & below works on Tomatoes, Peppers, and Eggplant... You can probably make out the other abbreviations like EB & LB, DM (Downy Mildew), Alter Blt = Alternaria Blight, etc, etc.

Nu-Cop 50WP (EPA 45002-7) OMRI, REI 24 hrs (77 % cupric hydroxide, equiv. 50%) (Albaugh). T EB, LB, Bac. speck and spot, Anth, Septoria varies 2-4 lb/A; E Alter Blt, Anth, Phomopsis, 2 lb; P Bac. spot, 2-3 lb. Approved for greenhouse and shadehouse crops on label. 0 DTH. See also Nu-Cop 3L and Nu-Cop HB for use on TEP.

They get expensive, or only available in larger quantities unfortunately... for example, Nu-Cop 50WP is about $4/lb, but sold in a 20lb bag for $79.

Potassium Bicarbonate is only listed by one company to treat Septoria, but it's mostly for Powdery Mildew. Prices can be high again... the one claiming it can be used against Septoria Leaf Spot is Armicarb 100 and O Eco-Mate (EPA 5905-541-AA) at $264 for a 40lb bag.

By the way, Neem and Serenade & Rhapsody & other biologicals aren't listed for Septoria.

(No wonder so many people use Daconil/Chlorothalonil @ $14!)

Hope this helps.

    Bookmark   August 1, 2010 at 11:41PM
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nygardener(z6 New York)

Thanks! I was hoping to avoid chemicals and copper-based fungicides. I'd like to find something benign that will help at least slow the fungus, together with picking affected leaves or other practices. Has anyone tried or found something that works in your garden?

    Bookmark   August 2, 2010 at 11:30AM
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(No wonder so many people use Daconil/Chlorothalonil @ $14!)

no wonder they still find hexachlorobenzene (HCB) in drinking water and food sources even though it's use as a stand alone product was banned 1965.

Every time one sprays chlorothalonil, which is contaminated with HCB and one of the most widely used fungicides on food crops, lawns, golf courses and ornamentals, they are exposing the environment to more.

And like so many other toxic wastes, isn't it a great deal for the companies to charge us to get rid of it rather than for them to pay to dispose of it?

Anything you can do to keep foliage dry helps prevent septoria and other foliar problems. Create air flow. Space plants farther apart or try and build a cover to prevent rain from getting on plants (modfiied hoophouse with raised sides). Clean up all tomato debris and remove weeds in the area like horsenettle and other nightshade weeds so that there is less fungi overwintering.

Here is a link that might be useful: hexachlorobenzene

    Bookmark   August 2, 2010 at 12:01PM
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korney19(z6a Buffalo, NY)

Hey muli, tell them what to use RIGHT NOW THIS SEASON THIS DAY because they'd rather not use organic approved copper. Hey, them are some good methods but some are impractical for RIGHT NOW.

Build a cover? Some or many here rely on overhead rain to water their plants. Others fear it. Spacing plants further apart? Impractical now unless in movable containers. Does SLS overwinter in NY?

Go ahead and just tell them what they can use now... but please be practical instead of an activist. How about milk, or baking soda, or vinegar? Sulfur? Anything? Please reread the thread title again, thanks.

    Bookmark   August 2, 2010 at 8:12PM
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I have been using the Cornell Formula for years but I'm lazy and some years I just don't bother. I did spray it two weeks ago. I grow organically and really let nature take it's course and I have no complaints. (For instance I fight bad bugs with good bugs, not sprays) Mulio's advice is excellent IMO. Proper spacing, a good thick organic mulch and a soaker hose goes a long way and I would consider that for next year. I just figure it's normal here for me to get yellow and brown leaves on lower branches each year. I am having a fantastic season even with the specs and spots with plenty of tomatoes! I don't think the Cornell is better than Daconil (I used Daconil many years ago in my chem head days) but I feel better about what my family, friends and neighbors eat...;-)

Cornell Formula:

1 Tablespoon each of Safer's hort oil and baking soda mixed in a gallon of water. A couple drops of dishwasher soap. Gotta keep agitating or it clumps up your sprayer. Good Luck!

    Bookmark   August 2, 2010 at 9:16PM
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nygardener(z6 New York)

mulio, the plants are 3 to 4 feet apart in 30" diameter cages and seem to get plenty of air flow. I use drip irrigation. Could try covering them next year, but I like exposing the plants to rain.

Thanks, bigdaddyj. Has anyone found that the Cornell Formula helps with existing cases of Septoria (or other fungal diseases)? Would it work just as well without the oil?

    Bookmark   August 2, 2010 at 9:33PM
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I don't know how it would work without the oil but like Daconil it's a preventative and not a cure. It seems to me that it does slow down the spread of the lower yellow leaves from climbing upward. I sprayed it this year because I noticed almost overnight that my plants lower leaves yellowed quite a bit on certain varieties and weather forecasts called for more soupy humid nights. It seems to have worked. I still have plenty of nice healthy green leaves on almost all my plants and they are thriving...:-)

Here's a pic I took about a week ago. You can see the bottom of two very tall Claude Brown's NOT Yellow Giant plants got the "yellows/browns" but the tops are still fine:

    Bookmark   August 2, 2010 at 10:42PM
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taz6122(N.W. AR.6b)

korney I think you need to reread the title. The first word is safe and IMO copper isn't that safe.

    Bookmark   August 3, 2010 at 2:34AM
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Septoria is a tomato plague I've accepted as a chronic problem in my garden. Early Blight, to a lesser extent, the same. I realize both are gonna be with me for as long as I grow tomatoes at this location.

I have used Daconil in very limited applications. Once this year. None last year. Etc.

The one time this year was on the transplants when they were about 12 inches tall and still in their 16-oz. cups but in flats sitting out in the raised bed exposed to weather ... just to arrest the spread after I severely pruned off the damaged leaves ... so that I could get some more planted into the beds and mulch them down against further splash back.

I have a bad horse nettle problem 'cuz I use compost made from horse stall bedding, manure, old rotted straw, and other nearby agricultural products many from fields infested with invasive seeds. I also have some wild solanaceous weeds. Whatever.

So, what can you do right now?

Weed your garden thoroughly.

Rake up all the waste and debris that has fallen to the ground.

Cut all the badly affected leaves off the plants and prune some more of the excess foliage out of your cages, like get the plants cut back to where nothing is hanging outside the wire for you to brush up against and spread the fungus from one plant to another. Think out the inside foliage a bit to increase air flow.

Carefully spray the wire low down on the cages with a solution of 1 part Clorox or Purex with 10 parts water. Be very careful to just spray the wires and let the bleach solution fall to ground without hitting the stems. You might kill a few leaves, but when I've sprayed my house gutters with a stronger solution of bleach and it fell on tomatoes growing under the leaves, yeah, I got some leaf damage but didn't kill any tomato plants. Just sayin' ...

Re-apply the mulch around and between the cages, stuffing some fresh straw into the cages to prevent any more splash back.

After that, if you still have severe Septoria on certain plants, like spots on the fruit and wilted leaves covered with advanced spore growth, remove the entire plant and take the cage out of the garden for a thorough disinfection with the bleach solution.

Next year grow varieties known to be tolerant to or capable of outgrowing Septoria. I have not found a variety 100% resistant to Septoria, but some varieties will withstand or outgrow it.

Listed in order of ability to withstand Septoria in my heavily infested bed:

Mountain Magic - nearly bulletproof

Chello (a gold, open pollinated cherry) - no problems ever

Red Brandywine, Landis Strain - awesome tolerance

Druzba - almost as tolerant as was RB, Landis

Sun Gold - nearly bulletproof

Indian Stripe x Sun Gold - intermediately bulletproof (LOL)

West Virginia 63, also intermediately resistant to Late Blight

Indian Stripe - decent tolerance to Early Blight and Septoria but eventually will succumb to Septoria later in season, never seen it go down to Early Blight though

Bear Creek - Had lots of Septoria on lower leaves but vine persisted in nearly rampant growth, set and ripened fruit form palm-like upper fronds while lower stems were completely denuded. Last plant in garden in fall to produce and ripen decent tomatoes.

Daniels - fairly tolerant and reported to be tolerant to Late Blight, too. Yeah, it got Septoria but it went on to produce good, sound fruit and basically outgrow the plague.

Mozark - a determinate that may get Septoria but will still set and ripen a concentrated crop (40 - 50 tomatoes) before succumbing, the tomatoes will be red and ready.

Mozark x Sioux - good so far this year while others on both sides went down

Ananas Noir - completely free of Septoria until late in production cycle

Traveler 76 - after a severe bout early was able to outgrow and withstand

Cherokee Purple - same comment as Trav. 76

I'm sure there are others, but none I know of will be completely Septoria resistant.

If you don't want to use chemicals on your plants, and even "organic" fungicides are in fact chemicals ... just from organic rather than synthetic sources ... then you're gonna have to go with tolerant or intermediately resistant varieties and employ good cultural practices like ...

Spacing to enable air flow and movement thru the garden without carrying spores on your clothing

Pruning to remove all diseased foliage and create better air flow

Heavy mulching with successive applications of dry, clean staw

Complete removal of severely diseased plants

Sanitizing cages, tools, gloves and other clothing, etc.

Removing weeds and garden debris, tilling under the top layer, applying cover mulch over the winter.

    Bookmark   August 3, 2010 at 12:25PM
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Disease prevention begins at seedling plant out. There are biocontrols out there that can control Septoria leaf spot but most act as a preventative. Once you contract the disease it is very hard to eradicate organically. "Green Cure" fungicide's discription say's it is effective against Septoria. Some folks use diluted Bleach (Sodium Hyperchlorite) for foliar diseases and swear by it. But prevention is the key and must be used during the life of the plant.Ami

Here is a link that might be useful: Cornell

    Bookmark   August 4, 2010 at 4:44AM
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nygardener(z6 New York)

Thanks, hoosiercherokee. I've weed-whacked between rows, cut out the weeds near the plants, and pulled out spotted leaves. I think next year, to improve air flow, I may use wider cages (mine are 24-30" in diameter) and space the plants even farther apart (they're about 4' now).

miesenbacher, you say that There are biocontrols out there that can control Septoria leaf spot but most act as a preventative. Can you name some?

I sprayed all the plants with Serenade, a bacterium-based organic fungicide that's supposed to be benign to soil organisms as well as beneficial insects. It seems to have slowed the spread of Septoria on all but one of my plants, enough that I think I'll be able to get them to harvest without too much damage. If that doesn't check it, I'll probably skip growing tomatoes for a year or two to cleanse the soil, because it's pretty discouraging to grow 150 pounds of tomatoes and harvest 20.

I just pulled the one plant (a Gregory's Altai) that still showed rapid spotting, as well as signs of early blight. It broke my heart to pull it, because it had 45 green fruits weighing about 30 pounds. Some of those may ripen off the vine ... or I may try again to develop a taste for fried green tomatoes ....

    Bookmark   August 8, 2010 at 9:01PM
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korney19(z6a Buffalo, NY)

Hey Taz, if Espoma Garden Tone or Plant Tone had 23 times as much arsenic as Miracle-Gro, would you still use the Espoma products? One of those two DOES have 23-24x as much arsenic, yet it's widely used because people believe it's organic and arsenic isn't considered dangerous in such low amounts. Is it safer than organically approved copper? Which is worse? Which is more scary?

    Bookmark   August 9, 2010 at 4:06AM
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nygardener(z6 New York)

I think I've made it pretty clear what kinds of remedies I'm interested in, and copper-based fungicides aren't one of them. If anyone's interested in arguing about whether some organically-approved methods are more dangerous than some chemically-based methods, etc., please start another thread.

    Bookmark   August 9, 2010 at 4:59AM
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taz6122(N.W. AR.6b)

korney I don't and never have used Epsoma products.

Serenade has septoria listed on the label. You might look into that.

    Bookmark   August 9, 2010 at 2:44PM
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korney19(z6a Buffalo, NY)

I think I said this in my very first post which I spent a lot of time on--Serenade and Serenade MAX are listed for the following uses, but not for Septoria:

Serenade ASO (EPA 69592-12) OMRI (Bacillus subtilis, biological), REI 4 hrs (AgraQuest); Field use EB, LB, PM 4-8 qts/A; Bac. Spot, 2-8 qts/A combined with registered copper. 0 DTH.

Serenade MAX (EPA 69592-11) OMRI, REI 4 hrs (Bacillus subtilis, biological) (AgraQuest); Field and Greenhouse Use Bac. Spot, Speck, EB, LB, Gray mold, 1-3 lb/A. 0 DTH.

Perhaps you should tell Cornell University's Dr. Zitter of the Plant Pathology Department that in your garden it also seems to have slowed the spread of Septoria. I'm sure he would like to add Septoria Leaf Spot to the lists above of what it's effective on. Perhaps you're using a weaker version with an additive not listed on the commercial strength versions above. Sorry I couldn't be of more help.

    Bookmark   August 9, 2010 at 3:02PM
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nygardener,This might interest you. Ami

Here is a link that might be useful: Biological and Microbial Fungicides

    Bookmark   August 9, 2010 at 3:22PM
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taz6122(N.W. AR.6b)

This is taken from the PDF label here.

Anthracnose (Colletotrichum spp.)
Bacteria (Erwinia spp., Pseudomonas spp., Xanthomonas spp.)
Bacterial Leaf Blight (Xanthomonas campestris)
Bacterial Speck (Pseudomonas syringae pv. Tomato)
Bacterial Spot (Xanthomonas spp.) - suppression
Bean Rust (Uromyces appendiculatus) - suppression
Black Mold (Alternaria alternata)
Black Rot/Black Crown Rot (Alternaria spp.)
Black Spot of Rose (Diplocarpon rosea)
Botrytis (Botrytis spp.)
Botrytis Leaf Blight (Botrytis squamosa)
Botrytis Neck Rot (Botrytis spp.)
Downy Mildew (Bremia lactucae, Peronospora spp., and Plasmopara viticola) - suppression
Early Blight (Alternaria solani) suppression
Fire Blight (Erwinia amylovora) Â suppression
Gray Mold (Botrytis cinerea)
Greasy Spot (Mycosphaerella citri) - suppression
Late Blight (Phytophthora infestans) Â suppression
Leaf Spots (Alternaria spp., Cercospora spp., Entomosporium spp., Helminthsporium spp., Myrothecium
spp., Septoria spp.)
Onion Downy Mildew (Peronospora destructor)
Onion Purple Blotch (Alternaria porri)
Phytophthora spp.
Pin Rot (Alternaria/Xanthomonas complex) - suppression
Powdery Mildew (Uncinula necator, Erysiphe spp., Sphaerotheca spp., Oidiopsis taurica, Leveillula
taurica, Podosphaera leucotricha, Oidium spp., Podosphaera spp.)
Rust (Puccinia spp.)
Scab (Venturia spp.) - suppression
Sclerotinia Head and Leaf Drop (Sclerotinia spp.)
Sour Rot
Target Spot (Corynespora cassiicola)
Walnut Blight (Xanthomonas campestris)
White Mold (Sclerotinia sclerotiorum) Â suppression

    Bookmark   August 9, 2010 at 3:29PM
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nygardener(z6 New York)

Thanks, miesenbacher.

And thanks to you, korney, for the recommendations. Thankfully, the label for Serenade does list Septoria, among others.

    Bookmark   August 9, 2010 at 3:49PM
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Besides many of the above recommendations, one may want to look at Green Cure. This is an organic fungicide suitable for preventing and curing many fungal problems. Attached is a PDF of the label:

The active ingredient is potassium bicarbonate

    Bookmark   August 7, 2011 at 9:06AM
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Greencure does NOT work for septoria. I have tried. Very little does except for copper and that is marginal.

Depending on which copper product you use, it can be more or less "dangerous". Many of the commercial copper products are very corrosive. I use CuEva from Certis, which imports it from Germany. It has been effective in slowing the spread of Septoria once it appears.

It is a soap with copper in it, just like insecticidal soap. It has a much lower amount of copper than most commercial preparations, yet seems to be just as effective. My guess is that the soap part acts more like a sticker/spreader and this makes the lower copper content safer.

Would I breathe it? No. Would I breathe water? No. Everything in life has a risk. Copper, when used correctly, is safe, effective and much less toxic than most other alternatives. A biological would be nice too, but remember, they are new and there is no long term safety studies, etc. etc.

If you are a commercial grower who is not using the normal fungicides, then you really have very little chemical options other than copper that are proven effective in multi-year trials.

    Bookmark   September 13, 2012 at 4:50PM
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I have some success foliar feeding a combo of milk, rock dust, molasses, kelp, compost tea. Sometimes I add some epsom salt if I feel like they'll appreciate it. It does seem to keep Septoria and blight in check and inspire the plants to keep living.

This year I experimented by giving my sadder-looking plants an end of season boost by way of an extra 3 inches of new compost and I got a lot of new healthy growth to compensate for some of the dying stuff below. You started this post a while back, so this may not be relevant, but I do get more fungal stuff towards the end of the season and I reason that part of it is just the natural tendency of everything to start dying this time of year. So, my theory is that you have to remind the plants that it's not over yet.

Anthropomorphize my plants much? Hell yeah!

    Bookmark   September 13, 2012 at 9:16PM
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I work for an organic farmer. Septoria is a fungus that infiltrates through a damaged area or the roots. I recently had a plat come down with it as well. I know you will not use a copper based fungicide, that being said plant require many things for a healthy immune system. If you are short on any of these then any problem in your soil will crop up in your plants. 1 item necessary to plants immune systems is copper. As for this year avoiding copper I would try feeding the bacteria in the soil as to try to get them to out compete the fungus, remove the effected leaves, water them without getting the leaves wet if possible and maybe try to add a protective fungus or bacteria, I would also be quite interested in applying an aerobic compost tea mixture. Will it work? Your guess is as good as mine. Prior to next season though I would pay for a $30 soil test through your local ag office and I bet you see that you are missing some stuff vital to a plants immune system most likely a very small but necessary trace of copper. Good luck.

    Bookmark   July 16, 2013 at 9:32PM
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drew51 SE MI Z5b/6a

Make sure you never consume stone fruits, as it is impossible to grow them without copper. Everytime you consume one you're encouraging it's use. No cherries, peaches, plums or apricots, in any form, organic or not.
Actually if you stop eating all together it would be better for the environment.

    Bookmark   July 17, 2013 at 10:41PM
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