I think Daconil is the best followed by Wettable Sulfur. Wettable Sulfur also has the virtue of killing the dreaded Tomato Russet Mite.

Yeah it's not a new discussion by any means and Daconil wins hands down unless you want to be strictly organic. In that case there are several different sprays that are probably equally effective but they must be combined with the many recommended cultural practices to be as effective as Daconil.

Of course the cultural practices are just as important as the sprays for all of us IMO.

Dave

Actinovate, actinovate, actinovate. Treat the soil with Actin-Iron, root drench with Actinovate and foliar spray throughout the season. NO PROBLEMS with disease whatsoever. Works on all plants.

Just wondering then...what are the major concerns with using Daconil? Obviously, many people swear by it as the most effective agent for preventing leaf disease. And I know it negates the organic gardening factor. But apart from it being a chemical agent, what are the real concerns about using Daconil. Is it considered really unhealthy? Or is it something like...just make sure to wash your fruit well once picked...

Don

The Daconil I bought was so thick it wouldn't spray in my sprayer. I guess just diluting it with water won't hurt if effectiveness?

Daconil is supposed to be diluted. Helps to read the label for proper instructions, and it is usable in most any sprayer assuming the sprayer is working.

Aside from the "it's not organic" I don't know of any concerns other than the standard garden hygiene - wash your food before eating it. Days to harvest spraying instructions are well detailed on the label. If a gardener uses other chemical sprays such as pesticides, fertilizers and such then Daconil poses no additional threats.

Actinovate can be used of course IF one has no objections to the systemic effects it has which Daconil does NOT have and IF suppressing fungi rather than preventing it is the goal. When used properly from day 1 Daconil works by coating the leaves preventing fungi adhesion.

Please also note that Actinovate list only the following:

"powdery and downy mildew, botrytis, alternaria. When used as a drench, it controls soilborne diseases including pythium, rhizoctonia, fusarium, phytophthora, verticillium, and other root-decaying fungi. "

It does not list any of the 3 blights nor septoria.

Dave

I have tolerated some fungal diseases in the past and never lost a significant part of my harvest. But like the OP, I plan to make a more consistent effort to prevent disease this year. I am going to follow the advice from larryw (1/19/12 post on early blight) and use a combination of actinovate and green cure (potassium bicarbonate) as a spray. I am also going to alternate with serenade. The actinovate prevents alternaria and late blight, green cure prevents alternaria and early blight and the serenade has some effect on those as well as preventing septoria.

I am concerned about daconil because of contamination with HCB and suspician that it is a carcinogen.

Here is a link that might be useful: Read about chlorothalonil problems on Wikipedia

If you are looking to go a different route, using beneficial microbes can help to boost a plants natural defenses. Mycorrhizal fungi can help a plant to fight off fungal diseases, while other fungi release toxins which help to destroy bacterial diseases. You can get one bottle of a root growth "innoculant" at many specialty plant stores (try a hydroponic store if you cant find this) which will contain 30-50 different beneficial microbes.
The downside to using these (if you want to call it that) is that you have to dechlorinate your water before using it to water your plants or else it will kill the microbes present. All of these are naturally present in the ground in places where there has not been chlorinated water poured on the ground to water it, and plants of all sorts will benefit from adding them.

Using dechlorinated water will allow you to also use other biological control methods such as Bacillus thurgenesis. This bacteria lives in the soil and can infect the larval form of mosquitoes and fungus gnats, and will kill them before they can become adults.

Also, you can use nematodes (microscopic worms) to control any pest which spends part of its life cycle in the ground. These little worms are applied through watering, and will begin to seek out intruders immediately. They will reproduce inside their hosts, leading to lasting protection.

From a nutrient standpoint, you can use silica to decrease the plants' susceptibility to a number of diseases, as well as to increase their overall strength. This results in larger plants, stronger stems, and less damage from insects. It is not an organic additive as it is extracted by chemical means,but I cannot find any problems with it so far.

If you have a pest problem and cannot get rid of it, or are looking for a preventative pesticide, use neem oil or pyrethrin spray. These are both pesticides which come from plant sources, so they break down in a matter of weeks. Neem oil can even be poured into the ground, where plants will absorb it and it will become effective throughout the entire plant. This keep pests from even wanting to feed on the leaves of treated plants. The bad part is, these also affect the good bugs when they are sprayed on the leaves, so try not to use them unless you cannot solve it through other means.

There are lots of organic means of pest control which do not wipe out the local pollinators and pest control bugs (ladybugs, parasitic wasps, beetles, praying mantis, bees, etc)
These can be even more effective than taking the "easy" route and just spraying to kill everything.

I could have sworn the Daconil I bought came in a sprayer bottle, thus not a concentrate. But I could be wrong. Anyway, I will be sure and pay closer attention to all the gibberish on the back. LOL

Jimmy

Just wondering then...what are the major concerns with using Daconil? Obviously, many people swear by it as the most effective agent for preventing leaf disease. And I know it negates the organic gardening factor. But apart from it being a chemical agent, what are the real concerns about using Daconil. Is it considered really unhealthy? Or is it something like...just make sure to wash your fruit well once picked...

Don

The generic name for Daconil is Chlorothalonil. The Wikipedia link I gave above gives this information, mostly from the U.S. EPA. Here's an excerpt:

Acute Toxicity: According to the United States Environmental Protection Agency, chlorothalonil is a Toxicity Category I eye irritant, producing severe eye irritation. It is in Toxicity Category II, "moderately toxic," if inhaled (inhaled LD50 0.094 mg/L in rats.) For skin contact and ingestion, chlorothalonil is rated Toxicity Category IV, "practically non-toxic," meaning the oral and dermal LD50 is greater than 10,000 mg/kg.

Chronic Toxicity: Long term exposure to chlorothalonil resulted in kidney damage and tumors in animal tests.

Carcinogenic Toxicity: Chlorothalonil is a Group B2 "probable human carcinogen", based on observations of cancers and tumors of the kidneys and forestomach in laboratory animals fed diets containing chlorothalonil.

Environmental Toxicity: Chlorothalonil is highly toxic to fish and aquatic invertebrates, but not toxic to birds. At a concentration of 164 micrograms/L, chlorothalonil was found to kill test a species of frog within a 24h exposure.

Contaminants: Common chlorothalonil synthesis procedures frequently result in chlorothalonil contaminated with small amounts of hexachlorobenzene (HCB), which is itself toxic. US regulations limit HCB in commercial production to 0.05% of chlorothalonil. According to the EPA report, "post-application exposure to HCB from chlorothalonil is not expected to be a concern based on the low level of HCB in chlorothalonil."

It's too much of a risk as far as I'm concerned.

As I said when you first asked this same question above:

"Aside from the "it's not organic" I don't know of any concerns other than the standard garden hygiene - wash your food before eating it. Days to harvest spraying instructions are well detailed on the label. If a gardener uses other chemical sprays such as pesticides, fertilizers and such then Daconil poses no additional threats."

It is a decision each gardener has to make for themselves. It is the same issue with the use of ANY chemical in the garden, balancing the risk of crop loss against the risks of the chemical. No one is advocating it for use with a mild case of one of the cosmetic disease where there is no loss of production nor for just a few plants nor for gardens with no history of problems. Other situations have to be evaluated by the gardener him or herself.

Personally when faced with severe chronic disease issues and the potential loss of 80-100 plants and their production, I find the risks associated with Daconil to be less than those associated with some of the other sprays as they act systemically within the plant and fruit itself rather than just as a coating as Daconil does. JMO

Dave

I get Septoria every year, I didn't know what it was until last year when someone from my same area (Orange County) posted pics of his diseased plants. I did some research and confirmed that that was what my plants were getting infected with.

On Daconil, just my opinion, but I'd stop growing tomatoes rather than use it.

Serenade simply isn't effective, at least for me. Tried it a couple years, spayed like clockwork and it really made no difference.

I also tried a cocktail of liquid seaweed, milk and Superthrive that someone recommended and had no luck with that either.

This year I bought copper spray, which I think is a good compromise between organic and chemical.

...sorry for the redundant posting,Dave. Didn't mean to re-post the same question. Not quite sure how that happened. LOL.

I've never heard of any of these brand names in Canada. We use a copper-based fungicide (brand name Bordo); it's commonly called Bordeaux mixture and can be homemade. Is my stuff more, or less, effective/toxic than what you guys are talking about?

Don, I feel your pain. I'm in San Diego and have experienced major problems in the last three years. By early July my tomatoes are losing all of their lower leaves and just look hideous. By August, I've usually given up (and they have too).

I've tried so many different things I don't know where to start.

This year, I hate to admit it since I've always been an organic gardener, I've decided to say screw the organic stuff. I don't want to lose 20 plants I started from seed. I've been spraying with Ortho Disease Control (pretty sure that has the same active ingredient as Daconil). So far, so good. They are healthy and lush and about 3' high. No signs of the first lower leaves turning brown and drying up but I guess that usually doesn't happen until sometime in May.

I also realized I have a liquid copper spray that I use once a year on my orange tree. Maybe I'll try that on the tomatoes instead of the Ortho thing. Thanks for creating this thread--some interesting ideas.

I guess living in So Cal comes with its blessing and curses. While plants may thrive, so do the garden pests/diseases.