Daconil for tomato leaf diseases...Arguments?

ladonJune 21, 2011

Ok...I've read a bunch of past threads about the use of Daconil on tomato plants. Last year I really struggled with leaf diseases... powdery mildew and verticillium wilt...maybe even some early blight. I used Serenade according to instructions on the label, but never completely got clear of my problems. I've avoided going the Daconil route, because I really want to stay organic...or at least as close to organic as possible...and Daconil just seems...well...kinda toxic!! But my plants are starting to show some early signs of leaf issues, similar to last year, and I thought I'd get some new opinions on the use of Daconil, since I know people are using it for tomatoes. I don't love the idea, but I don't want to have the same issues as last year either. Can you give me your best arguments and experiences both for and against the use of Daconil.

Thanks all!


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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

Daconil is a fungicide. It works as a preventative, not a cure, for fungus-caused diseases but has no benefit for viral diseases or mildew.


    Bookmark   June 21, 2011 at 9:04PM
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Hi Don,

I feel your pain. I've fought the dreaded onset of yellowing leaves and eventual demise of my plants.

Dave's right, Daconil is a preventative fungicide. I've tried both Daconil and the more organic approach of copper based antifungal. If you feel you have a fungal issue with your plants, read on.

I'm happy to say I've noticed a significant improvement of copper based antifungal over Daconil. The trick though, really is to start spraying once a week before the onset of problems. It still starts setting in eventually. I just have to keep removing yellowing leaves and spraying once a week.

Are you removing the affected foliage? That's a good start to get more life out of your plants. Treat it like toxic waste- don't let it touch any part of the plant as you remove it. Make sure to either burn it or completely remove it from your property. Wash your hands and shears really well before going back into the garden.

I found Daconil to be completely ineffective on both veggie plants and ornamentals. Although, others may find it useful.

    Bookmark   June 21, 2011 at 10:01PM
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The best combination I have found for foliar disease control is Actinovate and EXEL LG.It will work as a contact fungicide as well as a Systemic which will help fight disease from within the plant. Actinovate is organic and Exel LG is Bio-Friendly (Phosphorous Acid).

The idea is to keep the plant from getting disease by periodic applications rather than wait till your plant gets the disease and then try to eradicate it.

I also use Actinovate along with mycorrhiza and Biota Max as an innoculant which is applied to the roots via a dip prior to planting out. This helps the plant fight off soil borne disease as well as increasing the plants ability for nutrient uptake. Mycorrhiza and Biota Max are organic as well. Ami

    Bookmark   June 22, 2011 at 8:05AM
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Actinovate and EXEL alone probably would not hold up to high disease pressure particularly found on the east coast like Erin experiences in the Carolinas (there have been published studies which show only limited control with actonovate/exel combos). As Erin mentioned copper is probably your best "organic" solution. It could be combined in a rotation with Actinovate and EXEL and in that way you would reduce copper build up in the soil. Still copper must be used preventatively.

EXEL is not labelled for use on tomatoes in California.

    Bookmark   June 22, 2011 at 11:49AM
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sulfur is very affective against powdery mildew and is very safe for the most part, a mild solution of baking soda also works. as far as verticilium try to use resistant varieties, also as far as leaf diseases mulch is a great help ,to avoid soil spashing from the ground on the plants.
hope this helps


    Bookmark   June 22, 2011 at 1:47PM
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I sprayed all my tomatoes with Daconil this year because two heavy rain/hail events drove many of them to the ground and I was afraid they would contract fungal infections. So far I'm seeing no fungal problems at all in the 50 plants I have out, while last year, even without the same kind of insult from the weather I had extensive fungal problems. I know you can't prove much with negative evidence, but there you are.


    Bookmark   June 22, 2011 at 2:15PM
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Thanks for all the suggestions. I will check out both copper and sulfer solutions. But in regards to Daconil, what do you all think of it in terms, not only of effectiveness, but of safety. Is it safe to use healthwise? As for the copper and sulfer, which are the best products to get, in your opinions?

    Bookmark   June 22, 2011 at 3:03PM
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"Actinovate and EXEL alone probably would not hold up to high disease pressure particularly found on the east coast like Erin experiences in the Carolinas"

I am smack dab in the middle of the east coast here in Delaware and the Excel/Actinovate sprays plus mychro/Biotamax drenchs (2) have not helped. This is my first year trying these products. It's been awful conditions here since I planted out last week in April. Five varieties have yet to set a single fruit and some are 6 feet tall. EB and Septoria symptoms galore and each day I am removing diseased leaves and it's sickening. Johnny's F1 Defiant is so far laughing at all the disease riddled plants surrounding it though. Perhaps the future for us organic growers will be newer resistant types like Defiant. I will miss my tasty heirlooms....:(

    Bookmark   June 22, 2011 at 10:13PM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

But in regards to Daconil, what do you all think of it in terms, not only of effectiveness, but of safety. Is it safe to use healthwise?

Effectiveness - I find it exceptionally effective. Much more so than any of the copper-based solutions I have tried. But that is IF it is used properly from day 1 and on a regular basis and IF the threat you are preventing is fungal in origin.

As to safety issues - that is a personal decision and has to be balanced with the desire for fruit. Personally I find it safer than using lots of copper, especially since you don't spray the fruit just the leaves and you don't drench the plants, just mist them.



    Bookmark   June 22, 2011 at 10:51PM
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I had a lot of similar problems last year. This year I finally gave in and used Daconil on my tomatoes, honeysuckle, bee balm and grapes. (The four plants I had the most trouble with in year's past.)

So far, I haven't seen any signs of disease.

I hadn't sprayed the grapes at first and noticed some problems. Have sprayed twice since then and the rest of the vine seems to be disease free!

Like you, don't love the idea, but it seems to work. (And trying a bunch of products that are 'iffy' on results can be expensive and waste valuable time.)

    Bookmark   June 22, 2011 at 11:03PM
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zzackey(8b GA)

I used to live in Pa. I guess we just lucked out or grew the right varieties. I almost hate to recommend to use Vf plants. I always thought by hybriding a plant to be resistant you were losing flavor or giving in to chemists. maybe sometimes that is the way you have to go? I hate using chemicals of any kind. Sorry I can't offer more advice. my climate is so different than it used to be.

    Bookmark   June 23, 2011 at 6:15PM
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digdirt-Dave & scully931, are you guys mixing the Daconil per instructions? Is it leaving a white film/residue on leaves/fruits of your plants? I'm not sure how to spray the leaves without getting the tomatoes too.

There is much less diseased-leaves on my tomatoes, but the leaves are green but sorta wilted looking. I'm wondering if I mixed the Daconil incorrectly or I should use half-dosage next time. Or "mist" as Dave does instead of drenching it?

    Bookmark   June 24, 2011 at 1:02AM
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First off, this is a great thread, and I've learned a lot reading your experiences.

Second, I want to put in a vote for Neem oil. I've been using it this season from day one, and so far, no fungal infestations, and it's been a very cool and cloudy spring here in so cal. It's cheap (10 bucks for 8 ounces of concentrate that will make 8 gallons of spray), and as far as I know, it's organic.

Like other's have said, it's a preventative, and I still have a few lower leaves get mildly blighty, but the blight is under control and not spreading at all. I remove the infected leaves as I find them, and spray once a week, or before and after a rain.

It also is a mild insecticide and repellant, and so far I haven't had any major insect infestations.

We'll see how this holds up through the end of the season, but so far, I'm a fan.


    Bookmark   June 25, 2011 at 3:52PM
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msgenie516(z7 NY)

I actually purchased Daconil and then read the precautions, etc. and was afraid to use it and never did. So I can't really tell you how it works.

But, to avoid as much disease as possible, I always prune any bottom branches that touch the ground or will be soon. These are not fruit bearing branches and I never observed any harm from this, except that my tomato plants look a little bare at the bottom. I also plant them at least 3 feet apart (usually more).

The last time I did it, I actually noticed a sprurt of growth and fruitset shortly thereafter, so maybe this is actually beneficial for several reasons.

My plants still subcumb to some disease late in the season, but not before I get a good crop. Hope this helps, good luck! Genie

    Bookmark   June 28, 2011 at 2:35PM
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