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Old August 26, 2010   #1
gill_s
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Default Seed transmitted disease?

I have a severe disease problem this year on my tomatoes. At first I thought it was Tomato Spotted Wilt Virus but have now been told from a UK seed producer that it is almost certainly Bacterial Speck.(He refers to the 'Atlas of Tomato Diseases')
I have made extensive enquiries and not found any other incidence of it locally and have indeed not heard of any other in the UK. Does anyone know different? I have never had the problem before!
So now where has it come from? It can be soil borne or seed borne. I grow in 'grow bags' and containers using commercially produced potting compost mixes so this can hardly be the cause. I grow all my tomatoes from seed, not bringing in any 'unknown' soil or compost. It seems therefore that seed may be the culprit.
My main concern is how to go forward next year. Obviously I must be very rigorous about cleaning up my greenhouses and all tools and equipment and making sure all tomato and weed debris is removed from the outdoor growing areas also. I have quite a large store of seeds and would like to grow some varieties again next year.
How can I treat the seeds to rid them of this Pseudomonas Syringae? I have been given advice on a treatment for the seed coat. I have not been able to find out though whether this bacteria can be carried inside the seed.
Can anyone help with this information, please? I know that I could heat treat the seeds in a water bath at 122F for 20 minutes but this does reduce germination.
I am not sure which variety this started on. It spread very quickly so I would need to treat all my new 2010 seed varities.
In conclusion to this sad tale, it was to be my first year of seed saving! obviously that has had to be abandoned!
Please help with suggestions!
For information for anyone else with the problem two varieties which have shown good tolerance are Kumato and Sugary. All my other 65 varieties have succumbed, some worse than others!
Gill
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Old August 26, 2010   #2
Stepheninky
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This is what Cornell University says about it:

Bacterial Leaf Spot (BLS)

Bacterial leaf spot is caused by two major groups of bacteria, Xanthomonas campestris pv. vesicatoria and Xanthomonas vesicatoria (some literature will also mention Xanthomonas axonopodis pv. vesicatoria). A number of races occur for each of these pathogens, with some occurring more commonly on pepper and others on tomato. Both bacteria are gram-negative rods, have a single polar flagellum used for mobility, and are found only in association with plants or plant materials. The BLS pathogens are seedborne, both within the seed and on the seed surface. BLS may also survive on plant debris in the soil for 1-2 years, therefore a 2-year rotation out of pepper and tomato is essential.

Seed can be treated with hot water (122°F for 25 minutes) or with Clorox® (EPA Reg. No. 5813-1; label available from Clorox at 800-446-4686). Hot water is more effective for controlling bacteria on and within seed, but hot water can adversely affect germination if not properly performed (see ref. 3). Treating the seed yourself nullifies the seed company's liability and voids their guarantees. Mix 1 quart of Clorox® bleach (calcium hypochlorite) with 4 quarts of water to treat up to 1 pound of seed in a cheesecloth bag, add ½ tsp. of surfactant (dishwashing detergent), and submerge in the solution with agitation for 40 minutes, rinse under running tap water for 5 min, and dry seed thoroughly. Treated seed should be dusted with Thiram 75W [dithiocarbamate] (1 tsp. per pound of seed), and planted soon after treatment.



Use of disease-free seed and a 2-year rotation in the field should solve most of the BLS problems, but some persistent cases may require chemical treatments. Streptomycin (Agri-Mycin 17, Agri-Strep) sprays (1 lb per 100 gallons or 1 ¼ tsp per gallon) may be applied to transplants prior to transplanting. In the field, applying fixed copper (1 lb active ingredient per acre) plus maneb (1 ½ lb 80WP per acre) has been shown to reduce the spread of BLS.

So that tells me that bleach would probably be effective to clean surfaces and tools with and to sanitize containers.
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Old August 26, 2010   #3
beeman
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Quote:
Originally Posted by gill_s View Post
So now where has it come from? It can be soil borne or seed borne. I grow in 'grow bags' and containers using commercially produced potting compost mixes so this can hardly be the cause. I grow all my tomatoes from seed, not bringing in any 'unknown' soil or compost. It seems therefore that seed may be the culprit.
You don't think it might be supplied with the grow bags from the potting compost you bought?
I don't 'buy in' anything these days, having bought 2 yards of a triple mix which even grass wouldn't grow in! So much for professional dealers.
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Old August 26, 2010   #4
Wi-sunflower
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There is another thread here somewhere where "Randy G" posted about Bacterial spot and Bacterial speck. There is a difference but right now I'm not sure exactly what it is.
http://www.tomatoville.com/showthrea...bacterial+spot

From my personal experiences with Speck on Peppers (hot and bells) I can say that it's most likely that it came from infected seeds. From about 20 years ago it was a big problem on bell peppers. It would defoliate the plants and pock mark the fruit so it was unsellable. At university seminars the speakers highly discouraged using saved seed as that was often the starting point for the disease. That only commercial companies had the expertize to produce clean seed.

At that time I was big into unusual hot peppers that seed was very hard to come by so I DID save and use my own seed. I give all my seed a final bleach water rinse when processing prior to drying the seed. The thing is, for several years my own transplants for the hot peppers, my seed, were always clean. The only Speck I would find ALWAYS started in some of the hybrid bell seed that I bought.

As far as my tomatoes go, I haven't seen Speck on my tomatoes, tho this spring I MAY have had some Spot. I'm not really sure tho. Almost all the early set on my plants had spotting that I thought was Spot tho I saw no edivance elsewhere on the plants. After that first set the the fruit has been clean even tho we didn't spray anything at all. So I'm not sure what was on those first fruits.

If you bleach rinse your seeds when cleaning them, you should be OK.

Carol

Last edited by Wi-sunflower; August 26, 2010 at 10:04 AM. Reason: found thread
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Old August 26, 2010   #5
carolyn137
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Gill, lets go back to the beginning.

First, have YOU confirmed that it's Bacterial Speck or Spot by looking at some good disease sites such as Cornell or TAMU?

That the person had to check a tomato pathology book bothers me a bit. And the fact that the person you spoke to is with a seed company. Surely you must have the equivalent of what we call our Cooperative Extensions here. Yes?

Second, you've never seen it before, so you know it's being transmitted in an airborme manner, which is the most important method of transkission of ALL the tomato foliage diseases, including those two bacterial ones.

Have you looked at some pictures and confirmed that the spots on the fruits reflect either of those two bacterial diseases?

MY Seminis tomato pathology book says that seed transmission is a minor issue and that the major transmission is facilitated by cool RAINY weather and that the organism can survive on many crops and weeds.

You said you had 65 plants in gro-bags. You raised all of your plants from seed. I don't see seed transmission being the problem, what I see with such rapid transmission as you mention, is that your plants were infected via the pathogen being embedded in rain droplets.

So the seed you still have from raising all the plants should be just fine.

If you're absolutely confident that your plants have Bacterial Speck or Bacterial Spot, and the foliage appearance of the two is different, then if it were me I wouldn't save seeds from the fruits of the plants out there.

The various seed treatments suggested are NOT easy, especially the hot water bath method, and I think best left to professionals in terms of maintaining the constant temp needed.

The reason that the hot water bath method is suggested is b'c Bacterial Speck and Spot are found in the endosprem of the seed and NOT on the exterior, so any treatments that one might use to lessen, not eliminate, pathogens on the seed coat, would not work.

I hope the above helps and I do hope you confirm what the disease might be before too much longer. I don't think the disease, whatever it is, originated with you and your seeds b'c almost ALL of your plants you say were infected. Infection is NOT plant to plant, it's via wind and rain, so I think that's the way your plants became infected.

Are the plants dead? How far a long is the disease? Vigorous treatment with copper sprays has been shown to be moderatly effective, and the earlier in the season the better.
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Old August 26, 2010   #6
maf
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Quote:
Originally Posted by carolyn137
That the person had to check a tomato pathology book bothers me a bit. And the fact that the person you spoke to is with a seed company. Surely you must have the equivalent of what we call our Cooperative Extensions here. Yes?
Carolyn, unfortunately in the UK we do not have the equivalent of the Cooperative Extensions. At least not in terms of price. The Food and Environment Research Agency (fera) is probably the nearest equivalent, but the minimum charge for analysis is £65 (approx $100) which puts it out of reach of the average home gardener. See link: fera Plant Clinic Pest & Disease Identification Charges 2010-2011 (.pdf) . I can't comment for Gill, but if my tomato plants died of disease it would not be worth paying for the analysis. Of course if I was a commercial farmer I would pay up super-quick fast to try and protect my crop.
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Old August 26, 2010   #7
maf
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Gill, when first reading this thread earlier today I thought this seemed unlikely to actually be Pseudomonas syringae, but as I am no expert on tomato diseases I did not say so. I have seen different pathovars of P. syringae cause damage in woody plants here, most often winter/early spring dieback, but like you have never heard of it being a problem in tomatoes. It would be interesting if you could post some photographs of your infected plants, maybe someone could confirm the diagnosis or offer an alternative explanation.
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Old August 26, 2010   #8
gill_s
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Default Seed transmitted disease.

Thank you all for your help.
Carolyn, I have researched the disease diagnosis web sites and had to agree that it does look like Bacterial Speck. I had read that the strain of Pseudomonas Syringae that infected tomatoes was not widespread on other plants. The fact that I cannot find any other incidence of it nearby led me to think it was from seed or compost(I have still to investigate the sources of the compost).
My original post was probably misleading. This problem first came to my notice on one or two plants initially and then spread to the others going into the greenhouses last(maybe on my hands). If I could find any other gardens with a similar problem in the area I should be more than convinced that it had blown in on the wind. Maybe the mystery will never be solved but I shall endeavour to be disease free next year.
I shall send some photos but still need to find out how to do this so will send them in a different post.
Thanks again
Gill
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Old August 27, 2010   #9
gill_s
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Default photos of diseased tomatoes

Hopefully I have now managed to attach photos
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