bacterial speck

[TightenUp]

whats the preferred treatment?

been applying actinovate and exel lg weekly

[RayR]

Exel LG won't help against bacterial pathogens, it works only against Oomycete pathogens like Downy Mildew, Late Blight ect...
Actinovate may help, I don't know, it is now labeled to be effective against Bacterial Spot, but Bacterial Speck which is caused by a different bacterium is not listed.
Copper fungicides are used as bactericides to control Bacterial Speck and Spot.

[Mark0820]

Originally Posted by RayR

Exel LG won't help against bacterial pathogens, it works only against Oomycete pathogens like Downy Mildew, Late Blight ect...
Actinovate may help, I don't know, it is now labeled to be effective against Bacterial Spot, but Bacterial Speck which is caused by a different bacterium is not listed.
Copper fungicides are used as bactericides to control Bacterial Speck and Spot.

Ray,

Is it safe to use saved seeds from tomatoes grown on plants with bacterial speck or spot? I'm seeing varying information on University websites. Some indicate fermentation of seeds is acceptable, and some indicate a hot water treatment only.

[Cole_Robbie]

fwiw, The University of Illinois' publications recommends adding a little bleach to the soaking water. That should kill the bacteria.

http://ipm.illinois.edu/diseases/rpds/915.pdf

[RayR]

I think fermentation, then let the seed dry completely and then later doing the bleach soak method would be safer and easier to do for a seed coat infection. The hot water method is more complicated and prone to error without proper equipment.

[carolyn137]

As far as I know, all bacterial pathogens as well as viruses tested to date have been found in the endosperm of the seed so no surface treatments such as fermentation or Comet or bleach will help.

Yes, hot water treatment will inactivate the bacterial ones in the endosperm and the most important one for commercial growers is Bacterial Wilt and I'm sure some of you have seen comments in catalogs that hot water treated seeds are an option to buy.

Let the pros do the hot water treatment b/c if not done correctly there can be a huge loss of seed viability.

I have saved seeds from fruits of plants that have had Bacterial Speck or Spot and have not seen transfer of disease when those seeds have been grown out.

The major problem with seedborne tomato pathogens are the fungal ones, both foliar and systemic ones, which can and do adhere to the seed coat.

There has been good data from Dr. Helene Dillard who had several grants from I think Heinz, that most of the fungal pathogens were lessened on the seed coat by fermentation, but no data on same for oxidative methods.

So never are ALL fungal pathogens eliminated but since infection is a quantitative process it lessens the probabolity of infection when those treated seeds are used. Acid treatment is also used but mainly by those places that breed tomatoes, and/or do large scale seed production.

[Cole_Robbie]

Does the bleach water soak not penetrate the seed coat? (the testa, right?) I did not realize that.

[carolyn137]

Originally Posted by Cole_Robbie

Does the bleach water soak not penetrate the seed coat? (the testa, right?) I did not realize that.

No, the bleach water does not penetrate the seed coat, the seed coat is called impervious to anything as you can find if you do a Google search.

I found out when I contacted two tomato seed physiologists to ask them if any insecticides or anything else penetrated the seed coat in relation to those who were organic and concerned about that. Both of them said that nothing like that had ever been found inside the seeds.

Botanically speaking the tomato seed coat can be called the testa, but you're the first person I've known who called it that, b'c almost everyone else calls it the seed coat.

http://www-plb.ucdavis.edu/labs/rost...e/flrfert.html

The illustration in this link shows it as the testa but as I said, it really is called the seed coat by everyone.

There are always threads here asking what to do when germinating seeds don't shed the seed coat and I know I'd sit up and smile if anyone asked why the testa doesn't shed itself during seed germination.

[carolyn137]

(I never intended to try the hot water treatment, but I did consider throwing out my saved seed. It is a relief that fermentation is acceptable, and probabilities of infection are reduced. This must be why some Universities list fermentation as acceptable for spot / speck, and other Universities do not. )

******

Fermentation is accecptable to help remove fungal pathogens from the seed coat but not bacterial pathogens or viruses which are in the endosperm of the seed.

I really don't understand why some universites say that fermentation is acceptable for spot/speck when it's pretty well known that all bacterial pathogens that I know of, tested to date, and that doesn't include ALL of them, are found in the seed endosperm and fermentation does not and cannot inactivate bacterial pathogens in the endosperm.

Speck and spot are problems worldwide as major foliage pathogens and I know that hasn't stoppd me or many others from saving seeds which as far as I know have not transmitted those diseases. Those diseases as well as Early Blight and Septoria Leaf Spot are spread by wind and rain for all NEW infections, not talking here about splashback reinfection.

[RayR]

Originally Posted by Cole_Robbie

Does the bleach water soak not penetrate the seed coat? (the testa, right?) I did not realize that.

You don't want to soak the seed for too long, you don't want to hydrate the seed coat to the point where it penetrates into the endosperm. I don't know what soak time is recommended for different seeds, some seeds have harder seed coats than others.
Trisodium phosphate was also recommended to disinfect pepper seed, that's a easily available chemical and cheap enough

[carolyn137]

http://www.google.com/#sclient=psy-a...iw=757&bih=403

A general Google link explaining why TSP treatment is sometimes used, for it does inactivate TMV in tomato seeds as well as some pepper viruses in pepper seed.

But it's nothing I ever recommend since TSP is VERY caustic and can be a real problem with kids and pets as well as with adults who don't know how caustic it can be.

You can always tell TSP treated tomato seed b'c it's not fuzzy, the seeds are smaller than normal and the seeds are a dark brown to blackish color.

[Mark0820]

Originally Posted by carolyn137

I have saved seeds from fruits of plants that have had Bacterial Speck or Spot and have not seen transfer of disease when those seeds have been grown out.

The major problem with seedborne tomato pathogens are the fungal ones, both foliar and systemic ones, which can and do adhere to the seed coat.

There has been good data from Dr. Helene Dillard who had several grants from I think Heinz, that most of the fungal pathogens were lessened on the seed coat by fermentation, but no data on same for oxidative methods.

So never are ALL fungal pathogens eliminated but since infection is a quantitative process it lessens the probabolity of infection when those treated seeds are used. Acid treatment is also used but mainly by those places that breed tomatoes, and/or do large scale seed production.

Thanks Carolyn! This helps a lot. Initially (per another thread), my county agent thought my problem related to early blight jumping to the top of my plant. However, after four days of rain last week, it became obvious that wasn't the problem. It appears to be bacterial spot (could be speck, but less likely. According to OSU, spot is the most likely in Ohio). I have seen the tiny black spots on a few tomatoes in addition to many spots on the leaves (and the rain really spread the disease fast).

I never intended to try the hot water treatment, but I did consider throwing out my saved seed. It is a relief that fermentation is acceptable, and probabilities of infection are reduced. This must be why some Universities list fermentation as acceptable for spot / speck, and other Universities do not.