Amy,

Assuming it is early blight, which is one of the problems that shows up at this time of year (May-June timeframe), there is an entire range of products available. I'll run through them, starting with the MOST TOXIC and ending with LEAST TOXIC. You can then choose what you are most comfortable with using.

1. Over-the-Counter General Use Products Containing Chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile):

DACONIL (actually discontinued by mfg. but still available if stores haven't depleted their stock) 29% chlorothalonil

GARDEN DISEASE CONTROL by Ortho -- the replacement for Daconil I think, generally available wherever gardening supplies are sold. Costs roughly $15.00 a pint.

BRAVO--available in several formulations, containing from about 30% to about 80% chlorothalonil--more of a commercially-oriented product for ag users and forest service. If you buy Bravo be sure to the 30% one. That is the concentration the government rates as safe for use in vegetable gardens.

FUNG-ONIL by Bonide--essentially the same as Ortho Garden Disease Control

All of these are generally considered safe for use in the chemical world, but they break down into compounds that are toxic to fish and mammals. They are very effective though, and to be honest, they are more effective than anything we organic gardeners use. That doesn't mean I would use it. If used, protect eyes and skin as it may irritate them. Generally the MOST EFFECTIVE product available for treating blights. All these products use chlorothalonil from the same manufacturer so they are all pretty much the same, although one might be 27% active ingredient and another one might be 29%. They may have different inert ingredients.

2. COPPER-FUNGICIDES Copper products are the "big gun" in the organic world and some organic people use them. However, they are technically considered an Inorganic Fungicide and are used as a broad-spectrum foliar fungicide. They are somewhat effective but are not as effective as chlorothanlonil. I don't like using them as copper can also be toxic to fish and can cause a whole host of symptons/irritations to the person putting the copper products in their garden.

KOCIDE: Its active chemical ingredient is cupric hydroxide.

If you decide to use a copper product, please google and do some research on it first. I honestly think it would be safer to use a Daconil-type product than a copper-type.

The next three are probably equally safe (non-toxic) for use, but I put Seranade first because it might be more effective than the other two.

3. SERANADE--Organic Control For Disease, Insects and Weeds

This is the HOT new product of the year in the organic world. It is NOT a chemical but instead contains a patented strain of Bacillus subtilis (a bacteria) which is an ecologically safe control used by organic growers (OMRI-listed) to control a broad range of diseases, including anthracnose, downey mildew, early blight, late blight, leaf spot disease, powdery mildew, and much, much more.

I bought this at a Wal-Mart 2 weeks ago as soon as I read about its availability. It is in a red spray bottle with a yellow label and a yellow sprayhead. It has been approved by the EPA and USDA for use on food crops.

Some people on the tomato forum who have already used it on blight have been impressed, so I am very hopeful this product will give us a safe, organic product to use on blights.

4. An old organic solution is to spray your plants with a solution of baking soda. There are lots of formulas floating around. Here's one:
1 T. baking soda
1 T. dormant oil (I have used the Superfine summerweight dormant oils for this purpose in the past)
1/2 t. insecticidal soap or dish soap (to serve as a surfactant)
1 gallon of water

Mix together. Spray with a hand-sprayer or pump-up sprayer. Be sure to spray undersides of leaves too.

This is probably somewhat effective, but I haven't been thrilled with its performance in the past.

5. Garrett Juice--This is an organic solution from Howard Garrett, the Dirt Doctor, from the Dallas area. (www.dirtdoctor.com) I like Garrett Juice and use it for a lot of things. It is not so much as fungicide as a multi-purpose spray used to improve plant health. For reasons I cannot explain, though, it seems to help.

You can buy Garrett Juice in Texas at nurseries, feed stores, and even at some Lowe's and Home Depots, but I don't know if it is available in Oklahoma. I like buying the concentrate and mixing it up more than making it myself completely from scratch, simply because it is less time-consuming.

Start with 1 Gallon of Compost Tea -- If you buy a commercial compost tea concentrate, dilute it according to label directions. If using homemade compost tea, use 1 cup to 1 gallon of water.

To 1 gallon of compost tea, add the following:

1 ounce of blackstrap molasses
1 ounce of liquid seaweed concentrate or 1 teaspoon of powdered seaweed
1 ounce of apple cider vinegar

That is the general formula for Garrett Juice.

To use it as a fungicide, add 1/4 cup garlic tea and 1 tablespoon of baking soda.

Apply to plants with a sprayer, making sure to spray undersides of leaves.

Amy, are you absolutely sure it is early blight? Do you have the dark concentric circles showing up in addition to the yellowing of the leaves? If it seems like Early Blight, it probably is, but I hate to see you spraying for blight if you have something else.

To add to all the confusion of is it/isn't it Early Blight, here is a list of other problems for which yellowing leaves are a symptom:

too much water
too little water
zinc deficiency
iron deficiency
potassium deficiency
calcium deficiency
root-knot nematodes (only in sandy soil)
tobacco mosaic virus
aphids
tomatoes grown too close to the roots of a black walnut tree, or the use of a home-made mulch containing shredded black walnut tree leaves or wood

If the leaves are yellowing AND wilting it could be verticillium wilt or fusarian wilt, although I really have not seen them much at all in my many years of growing tomatoes.

I have battled early blight for years and years and years. I actually have had far less of it the last 3 or 4 years since taking pre-emptive measures to try to eliminate it before it can get onto my plants. Still, I think it is virtually impossible to grow tomatoes without eventually having to deal with early blight.

If you haven't had early blight before, ask yourself what is different this year. It is soilborne so it could be it just took it a while to find your plants.

If you have questions, let me know.

Good luck with the blight.

Dawn

Dawn-
Thank you for your comprehensive answer. You must be an encyclopedia of wealth of gardening info. I will try the Seranade first. I am truly scared it it nematodes, but am in denial. We have very sandy soil.
Thanks!
Amy

Dawn,

Do you spray your tomatoes regularly BEFORE the chance of early blight appears? I had such trouble last year with some sort of blight, but this year with our cool, dry weather (north of Edmond), not much chance for blight, yet.

I have the Seranade. Should I start spraying now? And how often do you spray?

Amy,

Let's just say I know a bit about early blight because it is, by far, the gardening problem I have the most experience with. Because I grow hundreds of tomato plants a year, I fight it constantly!

I hope you don't have root-knot-nematodes in your soil They are the hardest thing in the world to overcome.

If we have to choose between your yellowing leaves being an indicator of early blight vs. nematodes, let's hope it is early blight, because at least you can fight and sometimes defeat it!

Robolink:

I generally do not spray until I see early blight. Some years I see a lot of it. Weather contributes to it, as in rainy years we always have more foliage diseases on tomato plants.

I hope Seranade works for you, me, Amy and anyone else who tries it.

I would start spraying at the first sign of early blight. It is easiest to defeat it if you can get it early before it spreads too far. Once I start spraying for early blight, I usually spray once a week.

I have found it is easier to prevent early blight than to battle it after it appears in the garden.

Prevent early blight by mulching heavily, keeping foliage as dry as possible by watering with soaker hoses or drip irrigation, sprinkling corn meal on soil, planting plants far enough away that they have good air circulation (this is a rule that I often break!) and removing diseased foliage from the garden. Also, after touching plants with early blight, I wash my hands before I touch another one, so I don't spread the blight.

Dawn

BUILDING HEALTHY SOIL HELPS PRODUCE GOOD CROPS..
COMPOST, BIOCHAR, GLAZIER ROCK DUST, HUMATE ARE
JUST BASICS TO BUILD SOIL....STILL BLIGHT MAY POP UP ITS UGLY HEAD...APPLE CIDER VINEGAR LOWERS PH WHICH HELPS GET RID OF BLIGHT...I USED BRAGGS ACV, ABOUT 2 OZ TO FOUR GALS OF RAINWATER PLUS 2 OZ UNSULPHURED MOLASSES AND COMPOST TEA AND IT KILLED THE BLIGHT ON MY TOMATO PLANTS (DRIED UP AND DIED) TRY ON ONE PLANT FIRST....I LIKE FISH, SEAWEED, MOLASSES, ACV, HUMATE, FOLIAR SPRAY (H. GARRETT FORMULA) AND TOMATO TONE FOR FERTILIZER...IT TAKES TIME TO BUILD GOOD SOIL...ROY

FORGOT TO MENTION, ONE LADY FROM OREGON WHO LIVED IN OKLAHOMA SAID: I FOUGHT EARLY BLIGHT WITH EVERYTHING AND THE ONLY SURE AND SAFE WAY I RAISED TOMATOES IN OKLAHOMA WITHOUT AND TYPE OF BLIGHT PROBLEMS WAS WITH MAKE SHIFT GREEN HOUSE...OPEN AT BOTH ENDS, BUT DEW, AND RAIN NEVER GOT ON MY PLANTS...SOUNDS LIKE A PLAN...ROY

ONE THING FOR SURE, IF ALL TOMATO GROWERS FIGURE OUT HOW TO BEAT BLIGHT, THERE WILL BE TONS OF TOMATOES TO GIVE AWAY AND TO HOME CAN....BLACK PLASTIC COVERED WITH STRAW (TO KEEP COOL) IS WHAT I UNDERSTAND COMMERCIAL GROWERS PREFER....WE SHOULD VISIT THE AMISH PEOPLE, THEY PROBABLY KNOW HOW TO BEAT BLIGHT...THE INDIAN

Roy, Even with plastic, condensation occurs, including on the tomato plants themselves, when there is enough moisture in the air. I know this from experience because I raise hundred of tomato seedlings every spring inside a hoop-house style greenhouse and I have to get outside early each morning to open the 4 vents and 2 doors for better air flow. It doesn't prevent condensation from occurring, but with better air movement, the condensation dries up more quickly. We also have a large free-standing fan on wheels that I can wheel out of the garage and into the greenhouse for even better air flow.

I do grow my tomatoes with black landscape fabric placed on the ground as a barrier between the soil and the plant, with holes cut in the plastic when each tomato plant is transplanted into the ground. I put 2-4 inches of mulch (usually hay and grass clippings but sometimes chopped/shredded autumn leaves as well) on top of the black landscape fabric, and I have the same fabric and mulch in my pathways. Does it reduce the incidence of plants diseases? Yes, to some degree, but it only reduces the disease that would occur from soil splash. Since many plant diseases (including Early Blight and Late Blight) are spread by airborne spores, you still will have some disease issues too.

Having said that, I do get more tomatoes than we can eat and can. I usually can 200-300 pints of tomato products each summer, and then I freeze and dehydrate a lot more, and give away a bunch of fresh tomatoes too. So, even though we have some disease issues every year, we don't have a widespread problem that stops the plants from producing. They may look like crap during the height of the summer when Early Blight and other issues are abundant, but they rebound in late summer as the weather dries up and the plants then continue to produce until the first freeze.

If I could grow tomato plants any way I wanted and cost wasn't an issue, I'd grow them all in a high tunnel similar to my greenhouse, but I'd want roll-up walls on the sides for good air flow. The odds of me convincing my husband that we should build a large enough high tunnel to protect my tomato plants? Hmmm. Probably between slim and none. That doesn't mean I won't try to talk him into it one of these days. I might catch him on a day when he's in a really splendid mood and he might said "Sure, let's do that."

Dawn

ONE WAY TO FIGHT BLIGHT IS WITH SKIM MILK AND POWDERED MILK....A HEAPING TABLESPOON OF DRY MILK IN PLANTING HOLE....FROM CANADA SOME GROWERS DIP TRANSPLANTS IN SKIM MILK FOR 20 OR 30 MINUTES...J BAKER SAYS ALSO TO SPRINKLE DRY MILK ON TOP OF GROUND AROUND THE PLANT...MILK PRODUCES A HOSTILE ENVIRONMENT FOR BLIGHT....I AIM TO TRY MILK ON SOME PLANTS AND FIND OUT FOR MYSELF...ROY

THE AMISH PEOPLE I UNDERSTAND FIGHT BLIGHT WITH EPSOM SALT...1 CUP TO 5 GALS OF WATER AND SPRAY PLANTS HEAVILY AND THEN MAYBE ONCE MORE LATER...