Early Blight on Tomatoes – There’s Hope

I must admit I’ve always liked my way of gardening — keep it simple — let nature help you — and ignore most of what people say you can’t do.

And although I read Organic Gardening Magazine cover to cover for years, I’m almost glad I didn’t have the computer back then.  Information overload can be just as bad as not enough information.

I don’t like “complicated”. But in order to find out accurate information about most anything — especially something that you don’t know much about — it seems you have to do more searching than what is comfortable. (There is a lot is mis-information out there.) Fortunately that doesn’t happen often with me — but it did this year when I thought I had Late Blight.    Now that I know the few facts I need — I can continue on with “simple” —- which is what I prefer.

After the dust settled from my Late Blight fright and all the research — my earlier problem with Early Blight seemed “friendlier” and definitely something that can be avoided — or at least “lessened”.

Since Early Blight is one of the most common diseases of tomatoes in Virginia — I probably had it in my early years of gardening but just didn’t know what it was.  I do remember that I always had great crops of tomatoes and I NEVER remember leaves turning yellow almost as fast as I could pick them off.

In light of the above, I thought myself fortunate when I saw in a publication of the Virginia Cooperative Extension Service that Early Blight occurs to some extent every year wherever tomatoes are grown. (The indication was —“in Virginia” but I would think that would apply most everywhere.)

What is Early Blight

Early Blight is the most common leaf-spot disease on tomatoes and potatoes caused by a fungus named Alternaria solani.

Ironically, it rarely develops early.

It has a tendency to appear on mature foliage most especially after a heavy fruit set. (All my vigorously growing indeterminate tomatoes started to show signs of early blight this year just after their  heavy fruit set.)

Its beginning stages effect the leaves, but its advanced stage can cause fruit rot and stem lesions. I am happy to report it never got that far in my garden.

It is possible that the disease can spread to other members of the Solanaceae family (or nightshade family) like peppers and eggplant.  Fortunately, I saw no indication of this in my garden and never have.

What Early Blight Looks Like

If you do a Google search for ‘pictures of Early Blight on Tomatoes’ about 16 or more pictures will come up.  It’s a variety of looks but you should be able to find at least one that looks like your plants if indeed you actually have Early Blight.

I think the best way to describe the beginning stage is: irregular shaped dry patches which most of the time have yellow margins. Usually dark spots with concentric rings develop. If not removed, the leaves eventually wither and brown.

Caught by Surprise

In 35 years of gardening my tomato plants have always given me all the tomatoes I can use plus some.  I’ve never had to deal with a great amount of leaves turning yellow.  I have in the past experienced lower leaves yellowing and even an occasional “middle-of-the-plant” branch yellowing —- but not this kind of stuff where it starts and rapidly continues  to destroy your plant if left unchecked.

Where Does the Early Blight Fungus Come From?

Most of the time the fungus survives in the soil in plant debris that was infected with Early Blight. Thus, you would be far more likely to have Early Blight if you had it previously and did not remove the infected plant debris.

Spores can be carried on the wind for miles to your garden.  It can also be carried by irrigation water.  And once it lands on your garden soil – it can infect your tomato leaves (or potato leaves) by splashing onto them in a rain.

Can it come from your Straw?

It seems common sense to me that as prevalent as this disease is — it could most definitely come in on the straw you bring into your garden.

I asked a long time gardener about this — on a forum I frequent.  I found out that not everyone shares my opinion.  He said it is highly unlikely. I don’t agree.

Why I Wouldn’t Get Rid of my Straw even if I Knew for Sure it Brought in Fungus that can cause Early Blight

I depend heavily on straw.  I couldn’t garden without.  It would not be practical for me to remove the tons of straw I have in my garden. And most importantly, I feel there are better ways  to deal with this problem — and also ways to lessen the amount of straw I have to use. (I’ll cover that under cover crops below.)

I can understand the line of thought that would dictate getting rid of all the straw — either removing it or burning it.

Before you do anything like this I think you have to recognize that

• this fungus was most likely already in your soil BEFORE you brought your straw in.

The Severity of Early Blight Depends on Many Variables

Many fungi can already be in your soil — including the fungus that causes Early Blight — and lay dormant until the right conditions come along for them to thrive. I’m not only referring to the right weather conditions.

• If plants don’t have healthy soil  filled with organic matter and proper nutrients blight is much more likely to take hold.
• Drought and severe pest infestations can also cause blight to be much worse.

One thing I’ve learned over 35 years of gardening — nature specializes in variables. The variable might be so slight that the gardener doesn’t even notice — but nature does. How severe blight is in your garden can be very different from how severe it is in another garden.

Just keep in mind that stressed plants — whether from drought, lack of proper nutrients,  insects, or any other reason — will increase the likelihood of attack by Early Blight or any other kind of disease.

Recognize Generalities for what the are: Principles that have general validity — or — are true most of the time

Most of what I read online says that blight occurs in warm, humid weather with heavy dews and rain.  Most summers in Virginia are warm and humid, but I don’t always have blight. ( I say it like that to allow for the fact that I may have had it in my early years of gardening and didn’t know what it was. Generally speaking, I’ve just never had to deal with it.)

Much of what I’ve read said that blight will subside in dry weather.  That was not the case this summer when it was going strong in my garden despite a long dry spell.

My point here is to show — that although the generalities  you read about may be true —- they are just that —- generalities.  They do not have to be 100% true 100% of the time. And yes — you can generally look for Early Blight in humid – wet conditions, but a more accurate statement would be that Early Blight can occur over a wide range of climatic conditions.

When I finally Realized What Early Blight looked like I saw it on more than Tomatoes

As soon as I learned that what I had was Early Blight and could recognize it for that, I saw it on the fig bush that is outside the garden and the leaves on some of the surrounding trees.  Somehow — even though I had previously read  on Organic Gardening.com about it being on trees and ornamentals— it just had not registered with me until I saw it this year.

According the OrganicGardening.com:

• This fungal blight (Alternaria solani) infects ornamental plants, vegetables, fruit trees, and shade trees worldwide.
• On tomatoes, potatoes, and peppers, it is called early blight.

Unfortunately, I also saw it on my potatoes in the garden!  More about that in a minute.

The Beginning of My Course of Action in Dealing with Early Blight This Year

• I spent a good part of my garden time for six weeks removing and bagging infected leaves EVERY day and sometimes twice a day to get them out of the garden and keep spores from infecting more of the plant.  Bags of infected leaves were taken to the trash.

• I have tried to remove all of the discarded and fallen fruit since the disease can be carried on the seed.  I know that I’ve missed some, but I’m making an effort to get it all.

• I have spent a good deal of time thinking about what caused the outbreak of Early Blight to be so severe in my Garden this year when I’ve not had anything but a passing branch turn yellow in the previous 13 years in this current garden.

Think about What Could Have been Contributing Factors to the Severity of Early Blight on your Tomatoes

Most diseases are more severe when plants are stressed by not having the right nutrients or by drought or insect pests.  Early Blight is no exception.

I wrote down everything I could think of that might have contributed to the early blight. Here’s the list:

• The straw the farmer brought me could have had more Early Blight spores than previous bales. (I addressed how I felt about the straw previously.)

• When the foliage of my potatoes was about finished — it had the same tell-tale symptoms as my tomatoes with Early Blight.

My potatoes look like this EVERY year when they are about finished.  It looks like Early Blight. In years past the tomatoes were great looking even if the potatoes were in a bed right next to them. (Figure that one out!) To add to the puzzle — I have potatoes that I planted very late that still have beautiful green foliage that is just starting to die back.  No blight at all.

• In prior years I left every tomato vine and discarded fruit in the garden and piled straw on them after I pulled them up. I’ve done this ever since we’ve been at this location – the past 13 years, because the plants always looked healthy to me.  I totally disregarded the little bit of foliage that must have carried the Early Blight spores, because I have just not had any problem and didn’t anticipate any.

This year I will remove every tomato plant and every discarded tomato, bag them and trash them. (If you had Early Blight – I recommend you do likewise.) (Do NOT compost.)

• As I also previously mentioned,  the leaves of various trees had the same indication of Early Blight.  I have not paid attention in prior years, but I will henceforth just for my own record.

• We had very little rain this summer and to make matters worse we had an early drought in April.  Absolutely no rain in April left my garden beds much more dry than usual.  (I’m not set up to water.) My guess is that the early drought in April was a BIG contributing factor to stress on my tomatoes even though the tomatoes were not transplanted into the garden until May.  Usually my beds would have held enough moisture for quick growth that takes place then. To make matters worse, we had very little rain when fruit was heavy on the vines.  Perfect conditions for big time stress!

3 interesting observations:

• Every year I see one or two hornworms.  By the time I see them they have the cocoons of the braconid wasp on them and are paralyzed — so I leave them in the garden.

This year I saw at least a dozen or more.  Some did not yet have the cocoons on them.  I thought this was interesting since insects are more prone to attack plants that are stressed.

• After fighting Early Blight for 6 weeks or more — it just stopped spreading.  I can see some signs of it and some spots on the plants have dried up — but I think from something else other than Early Blight.  I’m not sure.  The plants have put out lots of beautiful new growth and have set fruit again.  I’m getting all the tomatoes I can handle.

 

• My tomatoes that get shade in the late afternoon did not get Early Blight until the last week that I fought the disease.  And as I said – it abruptly stopped spreading after that.  I’ve read many reports that  recommend planting tomatoes where they get the sun all day long.  But mine always seem to do better and produce more in places where they can be shaded in the hot afternoon sun after about 5PM.

Course of Action Now Will Help Next Year’s Crops

The key to not having Early Blight next year — or at least not having it to a great degree — is PREVENTION.  I plan to do everything I can to make my garden even healthier and inhospitable to Early Blight.

Removing all infected plants and fruit so that the spores will not remain in the garden is the first step. (Many folks dig it under, but I’d prefer getting all the spores I can OUT of the garden rather than leaving them in the ground.)   I’ll leave my straw. And I’ll plant cover crops in beds that have had tomatoes in them or that will receive tomatoes next year.

Do NOT compost infected plants or fruit.

Why Cover Crops and Which Ones

Tomatoes, potatoes, eggplant and peppers are the majority of my main crops and they’re all in the same family. I try to rotate them every 3 years, but it’s very difficult to do in a small garden where the beds are only separated by a few feet.  When you have small areas to work with, it helps to rotate this family of vegetables with cereals and legumes. Cover crops can be the answer.

Not only is the rotation itself helpful, but cover crops help suppress disease. What a bonus!

In beds where tomatoes have been this year and that I’ll use for early spring crops this coming year, I’ll plant oats and field peas.

• The oats will winter kill.
• The field peas will make it through until spring.
• In the spring I’ll use a small hand sycle to cut the oats and the field peas.
• The roots of the oats should be pretty much decayed.
• I’ll turn in the field peas and let the bed rest for a week or so before planting my early crops.
• The above-ground biomass from the oats and field peas will be place on tops of the bed as mulch.
• I’ll add straw on top if needed.

In places I plan to plant tomatoes, squash, cukes, peppers, and eggplant next year, I’ll put in winter rye (cereal rye) and field peas.

• They should grow robustly before hard freeze, remain alive through the winter, and then start growing again in the spring.

• I will cut the field peas and the rye with a hand sycle when the pollen is hanging from the rye.  That should be about May if the weather is somewhat normal.

• Then I’ll dig holes in the remaining stubble and transplant my late crops.

• The above-ground biomass will be laid on top of the stubble for additional mulch.  Hopefully I will NOT have to add straw as additional mulch until the summer is in full swing.

Rye is Harder to Incorporate than Oats

I’ll have to be careful with the rye because the roots are not as easy to incorporate as the roots of winter-killed oats. I’m only going to use it for beds I know will contain my late transplants as mentioned above.  This will give me a bit more time in the spring to work before transplanting time.

Even though rye is more difficult, I’m most anxious to use it where tomatoes will be.  The stubble and biomass should be enough mulch.  And more than likely I won’t have to add straw as mulch until mid summer. (That’s the plan to keep the straw away from the tomatoes.)

Why Field Peas?

I’ve added the field peas because they set nitrogen in the soil.

Just the rye and oats alone do a lot of good, but that extra nitrogen from the legumes (field peas) will be appreciated by the tomato plants next year.

I feel that using cover crops as part of my strategy is an excellent move.  And I think it will go a long way towards getting my tomato plants back to the healthy lush growth that I’m use to.

• A TIP: Unless you know what your soil really needs (via a soil test) don’t just add a lot of extra stuff.  To reduce the severity of Early Blight you want to avoid too much nitrogen and too little nitrogen or phosphorus.  I don’t want to be bothered with a soil test and I know my soil is healthy, so I just plant things that I know will work and let nature take care of it.  But — if you DON’T know — and plan to add various things — then have a soil test first so you’ll know what you’re doing.

Preventative Pruning

This coming season from day one I’ll prune off all leaves that touch the ground.  As the vines grow I’ll prune up to one foot or 18 inches above the ground. (With small indeterminate varieties of course you can’t trim that high up. Take out leaves that touch the ground on those.) This will reduce the number of leaves lost later when Early Blight arrives and will help eliminate the damp conditions the disease needs to spread by opening the bottom of the stems to air and light.

I love lush growth on tomatoes and have not done preventative pruning in previous years because it’s never been necessary.  But since this is where the disease starts (if it’s going to) — on the lower leaves —  I plan to make this preventative pruning of tomato plants part of my routine  — just in case.

Fungicides Might be Part of my Strategy for Prevention

As I’ve mentioned in other posts, I don’t like to spray — even with organic products.  Spraying is just something else to do and if I can find another way — I do.

However I’m considering adding some easy natural organic fungicides to my strategy to prevent Early Blight.

• If I can find organic cornmeal (the real stuff — not a mix) in bulk for a reasonable price I am going to broadcast it all around my tomatoes and potato beds.  (If you research this you’ll find it used a lot with success, but you’ll find just as many saying it doesn’t work.)

Many times when strategies seemingly don’t work, its because they were not done regularly and consistently.  You can’t be sporadic with theses fungicides and think they are going to work magic.  You have to be consistent and stick to the plan; otherwise, your time invested is lost.

• Another thing I’m considering (either in addition to the cornmeal or in place of the cornmeal) is Trichoderma Harzianum which is recommended by OrganicGardening.com.  It’s a fungus that is used as a fungicide.  According to Organic Gardening you can use it as a foliar application, seed treatment or soil drench to suppress other fungal pathogens. So far, I have only been able to find it at Garden’s Alive sold under the name of  Root Guardian.

I thought this would be good to drench my potato beds with after planting them.  When transplanting tomatoes instructions call for 1 cup of the mixture for each plant.

• It would be easy for me to incorporate spraying my plants with hydrogen perioxide.  I always have it on hand. It’s the kind you buy at the drug store or grocery store and is 3%.  You can dilute it with water or use it as is right from the bottle.

If you decide to use it straight from the bottle — test it on a small part of a plant for one day to make sure it doesn’t burn the plant.  I saw just a little bit of burning last year when I used it straight for something else; so, I just diluted it some and all was fine.

Other Fungicides

There are lots of things you can use for organic gardens for early blight. In addition to the three things I am considering, many folks have good success with a regular spraying of compost tea or seaweed/kelp spray. Other use a tablespoon of baking soda in a gallon of water with a few drops of liquid soap to make the spray adhere to the leaves.

Sulfur or copper are also used. (Not my choice as I covered in the post on Late Blight.)

Serenade, Sonata, Oxidate and Actinovate are other favorites.  For more on this refer to my post on Late Blight — the sections: What Organic Fungicides Should You Use?  and  Which Ones are Best?

Here is a link that lists all the fungicides that are approved for organic gardens. http://www.omri.org/simple-opl-search/results/fungicide

Your Best Chance for Success Using Fungicides

Whatever you choose — being consistent and sticking with it — is your best chance of success. Read instructions and spray as often as the instructions require.  If you’re using a home made spray with baking soda, peroxide, compost tea, etc. — you might want to do a little research to see how often others gardeners spray.  I would guess with most of these you’d need to spray every 4 days and certainly after a rain.

Most of the commercial fungicides recommend spraying every 7 to 10 days.

Make it easy for yourself and choose a strategy that you know you can follow through on.

Total coverage of the plants is imperative — so be sure you spray everything!

When to Start Spraying

For tomatoes start spraying two weeks before you expect the disease.  If the disease takes you by surprise — remove all infected leaves and start spraying immediately.

For potatoes – begin fungicide applications when plants begin to flower.

Other Basic Things to Keep in Mind for Preventing Early Blight on Tomatoes

• Start your own seed and follow good sanitation practices with your equipment and seedlings.
• Allow plenty of space between tomato plants.  Air and light will go a long way toward keeping things healthy.
• Use a mulch to keep Early Blight spores from splashing onto the plants when it rains.
• If you’re set up to water (I’m not) — water only when the soil is dry at least two or three inches down.  Over-watering is just as bad as drought for your tomatoes.  And water at ground level not overhead.  If you absolutely have to water overhead, make sure it’s sunny enough that the leaves will dry quickly.
• Cage or stake your tomatoes so they won’t be on the ground.
• Stay out of your garden when it’s wet.  And never work with your tomato plants when they’re wet.  Working in a wet garden will spread disease.
• If you’ve had Early Blight this year, consider pulling up all volunteer tomatoes and potatoes next year, since they will carry the disease.
• Try to plant potatoes and tomatoes where they will get the early morning sun to dry the leaves more quickly.
• Continually improve your soil by adding organic matter.
• Pay attention and check everyday for signs of disease.

• Be very careful of  seed you obtain.  And when you plant potatoes get the best certified seed you can.

Spores can remain on tomato seed. (Seeds that carry Early Blight can be one reason for dampening off of seedlings.)

This is important to consider and here are some questions that will help you to think:

• Are you getting tomato seed (or plants) from folks you know have disease free tomatoes?
• How do you know they are disease free? (That’s a whopper of a question!)

If you save your own seed — by all means please ferment the seed to have a better chance of the disease not transferring to the next generation.

I fermented and saved my seed this year since I’m developing heirlooms especially suited for my garden.  I feel the seed is “clean” and free from the disease. Do I know for sure? No.

Last but not Least in my Strategy

Years ago I use to plant about 10 tomato plants and got more tomatoes than I could possibly hope for — to eat fresh through December and to put up for the winter as sauce.

I now raise my own seed — so I plant a lot more.  In recent years I have tried new varieties and because of that I have increased the number of plants in my garden to approximately 40.  Most of my abundance of tomatoes comes from my tried and true varieties — not from the new varieties I try.

I’ve decided to decrease the number of plants, go with mostly tried and true varieties, and add one plant each of two new varieties.

The reason for this is two fold.

• I am preparing spots outside my garden for the tomatoes and I only have so many spots I can use. I hope to keep the garden tomato-free this year only.
• If I have only a dozen  tomato plants and decide on a fungicide spray program — I will be able to maintain what I start — and thus have a much better chance for success.

Final Thought

As upset as I was about Early Blight this year, I think my efforts to prevent it (or at least lessen it) next season —  will in the long run improve my entire garden.  And that fact is very exciting!

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Related Reading:

Late Blight – Know Your Enemy – Tomatoes – Potatoes

Organic Gardening is easy, effective, efficient — and it’s a lot healthier.

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