New study finds seed transmission of TYLCV

[alexita]

The site's search function doesn't work for me (I'm on mobile), so I hope I'm not double-posting this.

As if Tomato Yellow Leaf Curl Virus weren't bad enough, this recent study published in Nature found it can be transmitted through seeds. Their studies were conducted at two Korean greenhouse farms, and in a growth chamber at a Korean university where they tested a TYLVC-tolerant cultivar against a susceptible cultivar.

So, yeah. World's over? Someone come tell me why their methods stink and these results mean nothing.

[ginger2778]

Originally Posted by alexita

The site's search function doesn't work for me (I'm on mobile), so I hope I'm not double-posting this.

As if Tomato Yellow Leaf Curl Virus weren't bad enough, this recent study published in Nature found it can be transmitted through seeds. Their studies were conducted at two Korean greenhouse farms, and in a growth chamber at a Korean university where they tested a TYLVC-tolerant cultivar against a susceptible cultivar.

So, yeah. World's over? Someone come tell me why their methods stink and these results mean nothing.

Oh $hit!!!!

[alexita]

I was looking for whitefly mesh online when I found it. Totally messes up my plans!

[kurt]

I had my dance with the virus Oct.2015.I went into quarantine Nov.Dec 2015.Got rid of everything from that batch including whiteflys with the crud.Started fresh seed,mix, nuked containers etc.Now I have 6-7 footers bursting with blossoms.Having a nice little cool run down south here and all plants are alive and kicking.

[ginger2778]

Somebody pointed out it might just be on the coat, not in the embryo inside. The article doesn't specify. Fermentation should fix it if outside on the seed coat.

[alexita]

They state the seeds grown in the farm greenhouses were from fruit that was left to drop, which I imagine must go through a natural fermentation.

The seed grown at the university grow house were removed from the fruit, washed in distilled water, soaked in 70% ethanol for 10 mins. and then 10% Clorox for 20 mins. I can't imagine the virus not being inactivated and denatured if it were only on the seed coat. Then the embryos from unplanted seeds were carefully removed from the seed coat in sterile conditions and tested for TYLCV, which they tested positive for.

All I see is doom and gloom! Or is it gloom and doom?

[alexita]

Kurt, you only dealt with TYLCV once? That's really surprising and reassuring to me, considering you're in Homestead. You got any tricks you could share?

When I grew tomatoes in Kendall I had constant problems with it. I wasn't even close to agricultural areas. I could get creative to avoid whitefly for a month or two but most my plants succumbed to it. I only use bio control and mechanical pesticides though - I guess that's asking for it.

[Cole_Robbie]

These tomato plants had no visible TYLCV symptoms, but PCR results using the TYLCV-specific primer set showed that 17 plants from 20 randomly selected newly grown small tomato plants were TYLCV infected

If the plants had no symptoms, wouldn't they still grow ok? Are some plants carriers of the virus, but yet will never get sick from it?

And by the way, I had good results killing whiteflies with a product called Met52. It is a non-toxic bio-insecticide.

[carolyn137]

All viruses and viroids tested to date, as far as I know,have been found inside the seed,so surface decontamination/fermentation,etc.won't help.

For stuff inside the seed you have to use hot water treatment which is not easy for a home grower to do,and I'm sure you've seen in commercial catalogs the option of getting seeds for X that are or are not hot water treated.

And I'd fetch some links from the search function here if I had the time,but I don't,just enter hot water seed treatment,or similar and look for posts first,instead of threads.

Carolyn

[ginger2778]

Originally Posted by alexita

They state the seeds grown in the farm greenhouses were from fruit that was left to drop, which I imagine must go through a natural fermentation.


Yes, I thought of that too. I was just hoping.


The seed grown at the university grow house were removed from the fruit, washed in distilled water, soaked in 70% ethanol for 10 mins. and then 10% Clorox for 20 mins. I can't imagine the virus not being inactivated and denatured if it were only on the seed coat. Then the embryos from unplanted seeds were carefully removed from the seed coat in sterile conditions and tested for TYLCV, which they tested positive for.

Of course that treatment would denature most viruses. I missed that part of the article. Really doesn't look good. I think I might have to buy a sous vide for heat treating the seeds.


All I see is doom and gloom! Or is it gloom and doom?

[ginger2778]

I still love yellow sticky traps. They work so well. The whiteflies are strongly attracted to the yellow, and they last a whole season. It's the only thing that works for me. I just dont have whitefly isdues anymore, and hardly any leafminers either.

The little ones are whiteflies, the others are leafminer flies and other types of flies.

[alexita]

Cole, I'm having trouble following everything in the study but I think they must mean that the seedlings were tested for TYLCV before they showed signs of disease. Later in the paper they describe that the TYLCV-susceptible variety showed visible symptoms while the tolerant variety tested positive but did not appear diseased. They also included pics of some affected plants from another test where they went on to make sure that the infected seedlings they grew in the greenhouse would inoculate virus-free whitefly, and those whitefly would infect TYLCV-free plants.

And thanks, I love biocontrols and will look into Met52. Silverleaf whitefly is everywhere here, year-round, and I'm an urban gardener, so I don't think it would prevent TYLCV but could ease the plant's stress. I love living in what's effectively the tropics, except when it comes to tomatoes!

Carolyn, I appreciate the info! It sounded to me like the study was able to verify the virus was not limited to the seed coat, but there's a huge part of me that hopes there's some major flaw in the study. I mean, they did only test using fresh seed.

I'll check out the hot water treatment posts. A quick Google search says 50°C for 25 mins for tomato seeds.

[alexita]

Marsha, I read your yellow sticky trap post in one of the other subforums here where you recommended Seabright Labs, because they're not sticky to the point they'd trap wildlife. That's really helpful because that was always my hesitation using them at home. I need those lizards!

[kurt]

Originally Posted by alexita

Kurt, you only dealt with TYLCV once? That's really surprising and reassuring to me, considering you're in Homestead. You got any tricks you could share?

When I grew tomatoes in Kendall I had constant problems with it. I wasn't even close to agricultural areas. I could get creative to avoid whitefly for a month or two but most my plants succumbed to it. I only use bio control and mechanical pesticides though - I guess that's asking for it.

Pool enclosure controls the majority of insects."Outside"with all the fruit trees and assorted growths I do replenish a constant supply of green lacewings,mantis,parasitic wasps,ladybugs.In our area it seems the infestation of whiteflys has diminished a lot.I hear the county is releasing parasitic wasps,plus all the other cultural practices seems to help.I use the sticky traps "inside"for the maters and peppers.

[ginger2778]

Originally Posted by alexita

Marsha, I read your yellow sticky trap post in one of the other subforums here where you recommended Seabright Labs, because they're not sticky to the point they'd trap wildlife. That's really helpful because that was always my hesitation using them at home. I need those lizards!

This is where I get them. I usually get enough to get the free shipping since they don't go bad.
http://www.amazon.com/Yellow-Sticky-...w+sticky+traps