Viruses in TPS&Tomatoes seed ??

[Medbury Gardens]

I would imagine Tom would know the answer to this question,a question which was asked of me by a gardening friend while we were talking about the importation of vegetable seeds,i was asked why is it we can bring in all veg seed other than TPS and tomato seed,i thought it must be that the border control biosecurity people believe that potentially they can carry diseases or viruses,.....how much truth is in that??,or is it more to do with protecting our potato breeding industry.

[Tom Wagner]

I do what I can to prevent virus spread in my effort to share tomato seed and potato TPS. If I had to do the expensive testing and quarantining ….I would never get anything done or could not afford to pass the cost to the customer.

Although an early study reported seed transmission of TSWV at a high rate in Cineraria and tomato, a later study found onIy 1 percent infection. The virus is present only in the seed coat and not in the embryo. Seed transmission is thus not considered important for disease spread.

I treat all of my tomato seed and TPS with a combination of hot water, TSP, and chlorine and from healthy plants. As my treatment works great on the seed coat…I don’t think I am spreading virus in any worrisome capacity.

That said…reading further may settle your concerns or make you say…hmmmm.

Testing Methods for Seed-Transmitted Viruses: Principles and Protocols
A rather expensive book but here are some pages to read anyway. Goes to show that quarantine folks can get a bit asinine for good reason.
http://books.google.com/books?id=EY6...0virus&f=false
Potato virus T. ( PVT) is in Peru and they claim it can be spread by pollen and TPS. Outside of spindle tuber viroid…other virus organisms are not spread by TPS. I don't have either here in my inventory.

Depending on the quote...make up your mind already....

TPS is an efficient barrier against most of the tuber-transmitted diseases (Jones, 1982).
Vectors responsible for spreading PVT in potato crops are not known. It is readily transmitted through true potato seed and pollen (Jones, 1982)

http://www.bioversityinternational.o...che=1327331587 has page numbers where to view different virus strains.
Potato aucuba mosaic virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Potato black ringspot virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Potato deforming mosaic virus (Brazil) . . . . . . . .4 9
Potato latent virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 1
Potato leafroll virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 2
Potato mop-top virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Potato rough dwarf virus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 6
Potato virus A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 8
Potato virus M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 9
Potato virus P. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 1
Potato virus S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 2
Potato virus T. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 4
Potato virus U. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 6
Potato virus V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 7
Potato virus X. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 8
Potato virus Y. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 0
Potato yellow dwarf virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Potato yellow mosaic virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Potato yellow vein virus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 7
Potato yellowing virus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 9
Solanum apical leaf curling virus. . . . . . . . . . . . . . . . . . .8 1
Sowbane mosaic viru.s. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Tobacco mosaic virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Tobacco necrosis virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Tobacco rattle virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 6
Tobacco streak virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Tomato black ring virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Tomato mosaic virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Tomato spotted wilt virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Wild potato mosaic virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

[Medbury Gardens]

Thanks Tom,wow never realized there were so many Potato viruses.
So by the looks of it its just much easier for the NZ biosecurity folks to simply ban all TPS importations regardless of where it comes from and make those who do follow the expensively long drawn out quarantine procedure.
I wasn't sure whether it was because they had just lumbered tubers and TPS together into the same category as a way of costs cutting within there department.

How do you hot water when treating seed Tom?

[Tom Wagner]

Government regulations are set up to protect the interests of large growers and not to the small time breeders who are more interested in biodiversity and promoting new varieties. I do what I can to provide clean TPS to hobbyists. At least I doing more than most folks.

Since I put in a new water heater some time ago...I have it set to emit hot water somewhere around 121-123 out of my hot water tap. This temp also promotes a faster reaction of the TSP on the TPS. Same for the chlorine.

In the not so distance past....I had a heated vat of water controlled to keep the water at 121 F. and had test tube holders in the water with each test tube containing the seed in a bit of water. I left the tubes sit in the churning vat of water for about 30 minutes. I did that primarily for trying to eradicate tobacco mosaic from tomato seed. I was using fresh seed from tomatoes infected with that virus and the seed coats still had the viable virus until I learned how to eradicate the virus. I found out later that I could get rid of the virus over a two year seed storage program. The virus simply dies out during a period of its half life infectious rate of around six months.

[Medbury Gardens]

So that two year seed storage program,is that by storing it in the freezer??

[dustdevil]

Hi Tom.

What diseases are tomato seeds capable of carrying if processed by fermentation?

Dust

[loeb]

My grandmother used to soak cucumber seeds in fresh raw milk, before planting to get rid of cucumber diseases. Her cucumbers are always healthy. I always thought it was more magical, but 2 years ago I was talking with professional tomato grower, and she told me that spraying tomato plants with raw milk and water mix, helps to prevent tomato plants from virus diseases, because fresh raw milk is antyviral. Probably the thin layer of milk on a plant/seed helps to develop lactofermenting bacteria that are helping too..

[Tom Wagner]

I don't freeze seed and I even keep them at ambient temps. The half life of a virus? Complicated subject...out of time for that discussion. But....

As far as fermenting seed....I don't do it generally. I feel that tomatoes need an extended treatment or stand alone treatment with hot water, TSP, and chlorine.

Tobacco Mosaic Virus ....TMV in particular....is one of the major maladies I want to control in seed lots.

Rather than me explaining my take...read this link...

The most important virus diseases on tomatoes in North Carolina is tobacco mosaic virus (TMV), but other viruses may cause significant losses. There are many strains of TMV and a few which occur in North Carolina are very damaging. The common ones only cause a mild mosaic. TMV can survive many months outside a living plant or insect, on tools, greenhouse frames, sawdust, and in the soil; in dried leaves such as in cigarettes it can survive for many years. It is rarely transmitted by insects. It is easily spread by touch from diseased plants or from contaminated objects. TMV can be seed-borne; however, the magnitude of seed with virus in contaminated lots is usually under two percent, but with subsequent handling of plants all plants usually become infected before picking.

Management

From Stokes Seed...

Why is some of your seed treated? Seeds are treated to protect them from seed or soil borne diseases , thereby improving their performance for you. These treatments range from hot water, to treatments like trisodium phosphate (TSP sold as a cleaner) and chlorine (the same as people put in pools), to fungicides, such as thiram.

I grow organic and I don't use fungicides such as thiram. But I feel my use of TSP and chlorine is a necessary chemical treatment of seed that leaves not lingering harm to the crop or environment where the plants eventually get set out.

The next two links may in informative to someone

Tomato - Tobamoviruses link to TMV
Tomato - Xanthomonas spp. testing for bacteria

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[kurt]

http://www.aphis.usda.gov/import_exp...rts/faqs.shtml FYI you can search for tubers and mater seeds in the search block.