TSWV, bacterial speck, or something Daconil will take care of?

17 years ago

Hi Everyone,

I have 30 or so heirloom plants that have done great so far in my zone 7a central NC garden. This is my first year

gardening here with so many plants. However, in the last few days, I'm starting to see signs of danger :-). I have been spraying with Daconil once a week, and I use saponified Neem oil to control aphids etc. I have seen a fair number of green aphids, potato aphids, flea beetles, and white fly, but I have n't seen what I thought were thrips--even with a magnifier.

I'm attaching some photos of problem plants. The first two are Coyote:

I'm thinking it's TSWV and I need to yank it. The second photo is of top growth. Any confirmations are appreciated.

The second two are Lucky Cross:

Maybe preliminary signs of the same thing?

Finally, the last one is of Cherokee Purple:

There are more lesions like this one elsewhere on the plant. This looks fungal to me, right?

Thanks for any comments/advice. I hate to see things go down after so much hard work!

Mark

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Comments (10)

torquill
17 years ago
I'd say you're thinking in the right ways on these, Mark. Those purple spots on Coyote look bad to me, and when you added in the curled top growth I said immediately, "I'd yank it." Bacterial speck tends to be more toward the bottom and black, not purplish... and it can't cause that distortion. Only two things cause new growth like that in tomatoes: herbicide or virus. I'd pull it.

The second one is borderline; the real question is where the symptoms are showing up. Virus spots tend to show on newer growth, while bacterial and fungal things often show up more on the lower, older leaves. If you're getting leaves halfway up the plant or higher with that netting effect, while the leaves below are better or unaffected, I'd be betting on TSWV. If you feel daring, leave it in until it starts to stunt, and then you can be sure.

The last pic looks like Early Blight -- the broad halo is indeed a classic fungal symptom, and the edge-placement and brown dead area suggest Alternaria. Give the Daconil a try and pick off the affected leaves; mulching and clearing out the lower foliage may help as well.

It's always hard to pull plants, but you're doing well at keeping on top of things, looks like. Good luck.

--Alison
busy_bee_7tn
17 years ago
I'm so sorry to say that your pictures (minus the last one) look just like the TWSV I've been batteling for the last three years. Each year the virus has hit earlier in the season. First year I already had lots of fruit on the vines, so I went ahead and harvested as stuff ripened. Any that forms after the virus has happened, the fruit will not be any good.
This year I've yanked half my plants already and have very few green fruit formed.
I've tried relocating my tomatoes further from the roses that yield the thrips, but it hasn't helped.
Wish I had some answers for you.
Bev
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Okiebaker, Aw, c'mon now, tomato fever panic never cured anything, so relax and repeat after me "Growing tomatoes is fun and relaxing". Good. Now say it again. Take a deep breath. Feel better yet? Daconil is an anti-fungal agent. It coats the leaves and prevents fungal spores from attaching. It is not effective on bacterial infections. Copper spray is a fungicide/bactericide and is what you use for bacterial diseases on your tomato plants, whether you have bacterial speck or bacterial spot. The label of the product you purchase will give you the proper dilution rates and spray intervals. You can purchase copper products at nurseries, garden centers, big box stores or online. Be careful not to overuse copper because heavy overuse can cause copper to build up to toxic levels in your soil. Also, copper is toxic to earthworms and to aquatic life, so try not to develop an overdependence on it. Whether or not to remove the infected branch is a matter of choice. I tend to do it, but some folks don't. Be careful when removing it and do not touch anything else with your hands or your pruners until you've washed both or you could spreadthe bacteria to everything you or the pruning shears touch. Also, it is a judgement call in terms of removing a disease branch and how many to remove. If you remove too many, the plant will suffer a serious setback and developing fruit may lost its sun protection and develop sunscald. Most plants bounce back from bacterial speck and bacterial spot with minimal treatment. In future years, you should rotate your tomato plantings to another part of the garden or yard. If you repeatedly plant them in the same place, they'll have bacterial problems every year because it will build up in the soil. A 3-year or 4-year rotation is best, but even a 2-year rotation is better than nothing. Good luck, Dawn
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some have what to appers to be halos,you can see dark spots on the under side of the leaves also, it almost looks like pollen on the surfaces,but will not wash off). I looked at the tomato problem solver and I beleive that I have contracted bacterial spot or speck. I have about 50 plant in a 5x5 area and only I have to go with your diagnosis based on your looking at the Problem Solver pictures. Dark spots on top of the leaf surface with yellow halos I understand. Dark spots on the bottom of the leaf I don't b'c foliage diseases aren't usually defined that way. And I don't understand your reference to yellow pollen like material on the leaf surface. Could you please say more about that? Do you mean the area that we'd call the halo? it doesn't matter if it's Bacterial Speck or Spot b'c both would be treated the same way. And about the only thing a home grower has to use are copper containing preps such as Kocide, or similar. If it were me I'd spread out those 48 plants so that they have more room between them so that air circulation would be improved. Hopefully you can stop any new airborne infections from taking hold, but I must say that seldom have I seen a bunch of plants in ONE area where only TWO of them get infected and the others don't b/c all of them would be exposed to the same air that had the bacteria. All new foliage infections are acquired via airborne means, as opposed to splashback infection from contaminated soil from infections in a rpevious year. So I admit that I'm a bit puzzled here. Carolyn
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Fungal diseases such as early blight caused by A. solani require very different treatments than do bacterial diseases such as speck and spot. Fungal diseases are best prevented since the fungus is also airborne rather than treated after the fact and Daconil and similar products are the most commonly recommended preventative spray. Several studies show it to be the most effective since it lays down a protective coating on the sprayed surfaces thus preventing the fungus from taking up root (so to speak ;). And many have discussed it's effectiveness here in that past as you already know. Copper based fungicides are more for control of fungal problems rather than prevention IMO because the copper is toxic to the existing fungi (as well as some bacteria). And because the copper can also kill the plant tissue, and thus the plant, they carry a greater risk and require more care in use than does Daconil. Plus some studies now show copper-tolerant bacteria have evolved due to its many years of use. So, unless one is opposed to the use of synthetic chems which I assume you aren't, the Daconil will be much more effective in preventing the fugal problems without risk to the plants (assuming proper application instructions are followed). Bacterial problems have alternatives to copper products for control. The article from Ohio State linked below breaks down the differences between several different products on the market so you might want to review it for more details. Hope this is of help. Here is a link that might be useful: Controlling Diseases
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Since you've been spraying Daconil regularly, I think Septoria is less likely (as long as you've gotten good coverage). If it's been fairly cool, in the 65-70 range during the day (at least until just recently), you're probably looking at bacterial speck (Pseudomonas syringae pv. tomato). Since it's bacterial, Daconil won't stop the infection, and it likes cool humidity... it survives on weeds, seed coats of unfermented seeds, old tomato plant debris, and so on. The good thing about speck is that it doesn't threaten the plant's health at all when the plant is this size; it's a threat to seedlings, and not always then. It tends to go away as the weather warms up (though then you're more likely to see bacterial spot, caused by Xanthomonas). Bacterial diseases are slow-moving and combatted by taking off affected leaves, increasing airflow in the plant and, in bad cases, copper sprays. Most of the time a little isn't harmful. Pick off the spotted leaves, make sure you have good airflow in the plant, and don't worry about it too much unless it really starts multiplying a lot. --Alison
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pricem11
Original Author
17 years ago
Well, I yanked them out a few days ago. I HATE to have to do that. I had high hopes for Coyote since it was by far the most vigorous plant during the first few weeks and was the first to grow over the top of the cage.

So far, I haven't seen anymore of those tell-tale purplish spots and curly wilting of top growth.

In my hot and muggy NC garden, I'm seeing some yellowing and early fungal activity on a few plants--even hybrids like Sun Sugar and Better Boy. So I thought I'd share which plants are growing great, setting lots of fruit, and not a sign of pathology over here in this wonderland of bugs, virus and fungus called Chatham county Wink :

Arkansas Traveler
Azoychka
Black from Tula
Cherokee Chocolate
Cherokee Purple
Paul Robeson
Kimberly
Black Cherry

These plants are doing well with less direct sunlight than they should get, and their spacing isn't ideal either. How's that for staying power?!

Thanks for the previous advice and posts!

Mark
reeldoc
17 years ago
Help me with the theory of yanking diseased plants.......

I've read that most plant diseases are transmitted to the soil from the first diseased plant that was planted (which started the disease process in the first place). Since the diseases will never be removed 100% from the soil each succesive planting will also be susceptable to catching the disease, Theoretically speaking, you could end up yanking every plant that you plant in the future.

Why no leave them in and maybe see if they live long enough to produce?
pricem11
Original Author
17 years ago
This particular disease was tomato spotted wilt virus (TSWV). The major vector is thrips that transfer the virus to the plant as they feed. If other uninfected thrips come along and feed from the same plant, they can then hop over to a healthy plant and transfer the virus anew; hence yanking the plant out to prevent that. Also, the fruit from a TSWV infected plant looks, well, diseased. For other soil-borne or air-borne diseases, I wouldn't pull the plant if there was a chance to get decent fruit off it before it succumbs.
johnski
17 years ago
I'm getting dark leathery upper leaves on some of my plants. Could this be the same thing (TSWV)?

John
garyjoe
17 years ago
Top four are definately TSWV and I feel for you, AND me! I have been fighting it for years. This year we had early heat which delayed setting fruit on top of that! I'm looking into some BHN640, Amelia, and Top Gun which are supposed to be TSWV tolerant.

Gary
lee_71
17 years ago
John,

Not sure I could say one way of the other without a photo.

However the photos posted above are definitely good shots
of what TSWV looks like.

Gary,

I tried Amelia a couple of years ago when Fusion sent me some seeds.

It was an OK variety, but definitely better than nothing if you've got TSWV prevelent in your area.
Fortunately, I only have had to deal with it 2 years out of 7....

Lee
garyjoe
17 years ago
Hi Lee,
The diseases are terrible here in the Texas panhandle and it it is definately a challenge to even get a RED tomato in the basket! But I will keep trying different things to improve the chances if possible!

Gary
torquill
17 years ago
The one time I got TSWV (and it shocked me, I'll tell you -- I didn't think it was out here) I yanked the Mortgage Lifter as soon as I could confirm it, and haven't seen any sign in the two years since. It was one of those where the first sign was on the fruit, and it was just coming out with the purple spots as I pulled it. Definitely odd-looking fruit.

I'm glad viruses aren't soilborne... I have enough trouble with charcoal rot.

--Alison

TSWV, bacterial speck, or something Daconil will take care of?

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