Maybe a stupid question but I have to ask...

[Tomatovator]

Are "all" tomato diseases known and identified or are there unknown viruses, bacteria, fungi, etc. attacking our plants out there as well. Every year at least some of my plants get some form of ailment by the end of the season but often I cannot find pictures or descriptions of exactly what is going on with them.

[tlcmd]

In the for what it's worth department, as with human diseases, tomato diseases and pests haven't read the text books and don't exactly know how to behave. Since your problems occur toward the end of the season and appear to have no obvious cause, you might read up on tomato spotted wilt virus. Also, if you can find a TSWV resistant plant at a nursery, feed mill, etc, you might buy one and plant it in your patch. BHN 444 is a very commonly available one. Mine bore well into November last year as did another TSWV resistant one when all the rest of my plants were gone by mid-Sept.

Or you could "cheat" and take a diseased shoot from a plant to your local agricultural agent.

One of the other frequent (but can occur earlier) late season viruses is Tobacco Mosaic virus which will not kill the plant but cause it to decrease production and "look sick".

Try this link: http://www.ppath.cas.psu.edu/EXTENSI...rb.htm#tobacco

TMV and TSWV are the most common and widely spread tomato viruses over much of the country.This past winter and early spring I spent hours researching TSWV since that has been a real bugaboo in my garden. I've corresponded and researched state institutional agriculteral departments across the country from Mass to Georgia and Oregon to New Mexico as well as Australia from whence it came in 19188) and none had a solution for preventing the spread of TSWV (spread by thrips). I've gotten very aggressive this year and if you'll search my previous posts, I've described what I'm doing with companion planting, resistant plants, Grend Wormwood, Mexican Marigolds, reflective mulch, etc in trying to protect my 30 x 50 ft garden.

I've usually planted Parks Beefyboys and Parks Whoppers, neither of which are resistant to TSWV. I added BHN 444 and Bolseno last year which survived the TSWV onslaught. This year I've planted my non-resistant varieties within a perimeter of the resistant varieties and added Super Chromo F1, a TSWV resistant variety. In addition to the Parks varietis already mentioned I've added a Brandywine (Sud), Hillbilly, and Arkansas Traveler. Unfortunately, many of the heirloom varieties have very limited resistance, none to TMV and TSWV. I will admit, that in my side by side taste test, the TSWV varieties are not quite as sweet as the others, but, for me, it has to be a side by side test. Put them on the table mixed, and I can't tell a significant difference.

Hope this info helps.

[feldon30]

I thought Tobacco Mosaic Virus had been completely eliminated?

And TSWV is fairly straightforward to diagnose.


Tomatovator,

I would suggest taking lots of pictures of disease and posting them. If you need to take a picture of a leaf, either set your camera to Macro mode (it has a little picture of a flower on the button or dial) or pull the camera back and zoom in. Blurry pictures are of limited helpfulness.

[tlcmd]

Feldon 30,

I just completed a well documented discussion on another thread which was up to date with references from UMass to New Mexico and UMinn to N.C. with links and quotes which pretty conclusively show that TMV is the most prevelent virus threat virtually everywhere. I've appended 2 references below. How many more would you like?

Re: TSVW , it can be very difficult to diagnose. I've also done a fair research on that. If you'd like a list of reference links and copies of correspondence, some as recent as this week, I'll be happy to either post or PM them to you.
Please let me know.
Examples: from UMass at Amherst Agriculteral Extension Division and NCSU


Robert L. Wick (rwick@pltpath.umass.edu) Sent: Wed 7/23/08 7:51 PM To: Dick (tlcmd@hotmail.com) Dick:
It depends on how you define important, and whether or not you want to restrict
your observations to the northeastern United States. In our part of the
country, TMV is the most common virus of tomato but on the other hand, many
strains of the virus cause a fairly mild infection (some cause a severe
infection). Tomato spotted wilt virus is much more destructive of tomato but
less common on tomato than TMV. TSWV is actually more common on ornamental
crops than tomato for which it is named. Moving toward the south, tomato yellow
leaf curl virus is more destructive than TMV, and in S. Asia in particular TYLC
virus is more common and more destructive than TMV

Robert L. Wick, Professor
Department of Plant Soil and Insect Sciences
270 Stockbridge Rd
Fernald Hall
University of Massachusetts
Amherst, MA 01003

Link to full note: http://www.ces.ncsu.edu/depts/pp/not...notes/vg15.htm


Virus Diseases of Greenhouse Tomato and Their Managment
Vegetable Disease Information Note 15 (VDIN-0015)
Charles W Averre, Extension Plant Pathologist
Guy V. Gooding, Research Plant Pathologist
With the exception of TMV, most viruses attacking tomatoes survive only in living plants or briefly in insects.

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...

__________________________________________________ _________________
Note #5 Link to full note: http://www.ces.ncsu.edu/depts/pp/notes/oldnotes/vg5.htm

Granted that TSWV should have a straight forward presentation, frequently it does not. I'm minus minutes right now, but here is a single example of how TSVW can present in an unusual way. The initial signs of a plant infected with TSWV are frequently confusing and most University extension departments request samples from the plant to make a firm diagnosis. That's what I had to do 2 years ago. Anyway, check out this poor man's tomato patch:

Bacterial wilt -- suggestions please! - Growing Tomatoes Forum ...

Jul 6, 2008 ... Here is a link that might be useful: BW Resistance in Tomatoes ... (I thought I had TSWV but I still paid $20 for them to TELL me I had TSWV ...
forums.gardenweb.com/forums/load/tomato/msg071734589734.html - 101k - Cached - Similar pages

[carolyn137]

Yes, TMV can be an important disease in greenhouses as the heading for that report indicated, where it's spread manually to seedlings be transplanted.

The last large outbreak of insect transmitted TMV in a field situation occured about 20 years ago and there have been a few isolated reports from time to time since then, but not many.

But since the MAJOR US tobacco growers switched to using TMV tolerant tobacco strains the incidence of TMV has tumbled drastically. Turkish tobacoo is not TMV tolerant.

Not only are there several strains of TMV but most folks these days have more problems with CMV which also has several strains and some of them resemble TMV.

TSWV has not, to my knowledge, been a significant problem in PA where the poster is from due to lack of the proper kind of thrips that transmit it.

So why do breeders still introduce TMV tolerance into hybrids? B'c it's easy to do and is kind of expected with most modern hybrids.

And pardon me if I'm a bit cynical here, but so many folks look at the alphabetical disease tolerance designations after a hybrid variety name and think, great, resistent to everything. They don't realize that those are systemic diseases and most have limited geographical distributions and the most common tomato diseases are the foliage diseases for which no variety, hybrid or OP, has tolerance, with just a couple of exceptions that aren't useful to the home gardener.

I've been going thru this with my own brother who moved from up here to NC three years ago and I'm just not getting through to him. LOL He knows I know Dr. Randy Gardner, the well known breeder at NCSU in western NC and b/c the distance from that staion and my brother is only about 25 miles I think my brother wants me to ask him to drive up and Dx his tomato problems. Actually Dr. Gardner just retired on June 30th.

No way says his older but somewhat wiser sister.

[tlcmd]

Carolyn,
The scary part of TMV is that it can remain dormant for at least 40 and some investigators say 100 years. Even though the most recent infection rate in tobacco is less than 2%, if you handle tobacco products (and some folks even say tobacco smoke) you can introduce it into a tomato patch. Plus, it also is known to infect members of nine plant families, and at least 125 individual species, including tobacco, tomato, pepper, cucumbers, and a number of ornamental flowers. So while your tomatoes may well be TMV resistant, that infected cigarette someone tossed into your garden patch 40 years ago is still sitting there waiting for that heirloom that's not resistant.

If you've not been plagued with TSVW, great. Currently TSWV seems to be affecting the floral industry of Pennsylvania. Then Penn Dept of Agriculture says about TSVW in Pennsylvania:Tomato spotted wilt virus (TSWV) was first detected in 1987 on New Guinea impatiens. Since then, the host range has widened to 46 hosts. TSWV-infected impatiens, tomato, ivy geranium, New Guinea impatiens, and dahlia amounted to 45% of all TSWV-infected greenhouse crops tested. An average of 3.5 new hosts of TSWV have been identified per year since 1987.

All symptomless plants in the major hosts categories, including "pet plants," should be considered as the probable source of INSV and TSWV. One grower who had a "pet plant," perennial garden loosestrife, was informed that the plant was infected with TSWV on March 21, 2000. TSWV was found on that grower’s tomatoes and spiderflower on May 21, 2000, and then on the grower’s chrysanthemum on July 21, 2000. Through the cropping sequence in that greenhouse, spiderflower (Cleome sp.) became an additional host of TSWV.

The Link: http://www.agriculture.state.pa.us/a...w.asp?q=128047

TSVW (and TMV) seems to be almost ubiquitous. And if you ever find it in your garden on anything, confirm it via your state extension division and consider using TSVW resistant seeds and plants the next year.

I have a very personal vendetta against TSWV since it wiped out my garden (not just tomatoes) 3 years in a row before I had time to figured out what it was (with the wonderful help of our county farm agent).

I'll try to post my results with combating it this fall.

[carolyn137]

The scary part of TMV is that it can remain dormant for at least 40 and some investigators say 100 years.

****

Doubting Carolyn that I am I have a hard time believing that.

ALL viruses, whether plant, human, animal or avian, are obligate intracelluar parasites and cannot exist outside of a LIVING cell for any significant period of time.

The only exceptions, as shown with a few human viruses such as influenza, is if they were frozen in situ ,meaning in the dead frozen bodies of victims. Exhumation of such frozen bodies showed what serotypes/antigens were responsible for the major influenza epidemic of the late 1900 teens.

Viruses are simply protein capsid shells with either DNA or RNA for genomes and have no wholy effective outer protective layer and thus are not all that stable outside of a living cell.

While I haven't researched TMV as to studies showing longevity in the environment, and won't be, it is true that TMV has been known for about 100 years and has served as a model system for many kinds of studies that now include even nanotechnology type experiments.

The major incidence of TMV infection today is manual transmission from contaminated hands of workers who smoke cigarettes that do have TMV associated with them, and that wouldn't be USA tobacco, rather turkish tobacco as I mentioned above. And simple hand washing with soap destroys the virus on the hands.

And yes, TSWD has been a real problem in the floral industry in many places and that includes PA.

Again, the major problem for we home growers, as opposed to commercial growers, is CMV with about 800 different species as hosts, not TMV.

[carolyn137]

Are "all" tomato diseases known and identified or are there unknown viruses, bacteria, fungi, etc. attacking our plants out there as well?

****

I just realized that no one had addressed the question you asked.

I think I'd say that the diseases that affect tomatoes in the US are pretty well known and described, for several reasons, and that most new pathogens are imported or evolve by mutation from existing strains.

The bacteria and fungi and viruses and nematodes that can and do cause tomato diseases are always subject to mutation and that has been a problem and has resulted in different serotypes/races/strains, whatever you want to call them, enlarging the capacity for some of them to find new host species as well as changing some of them so they can actually infect better b'c of no cross protection.

What I mean by that is that originally only race 1 of Fusarium was known and then a new race was IDed and then a third so that now there are three races of Fusrium and no cross protection between them.

Originally there was only one strain of TMV and one of CMV and now there are several different strains of both.

And there are many other examples.

[tlcmd]

Doubting Carolyn that I am I have a hard time believing that

Doubting,
Many viruses and bacteria live in a dormant stage that only becomes active when it is introduced into the proper environment. The best example is tetanus. Tetanus spores are virtually everywhere in the soil.
TMV also can remain dormant for years (the shortest I've read is 40 years). Here is a reference link from NCSU and what they have to say about it is appended below. Gotta run, but will provide as much info and references with links from respected agrucultural institutions as you desire.

Link: http://www.ces.ncsu.edu/depts/pp/notes/oldnotes/tb1.htm

Properties of the Virus
Tobacco mosaic virus, like other viruses, is a very small chemical particle that can multiply only in a living host and only can be seen with an electron microscope. It differs from other viruses that infect tobacco in two ways that are important in its control. First, TMV is very resistant to destruction. It will survive for at least 50 years in dead, dried tissue while other viruses become inactive when their host plant dies. Second, TMV is primarily transmitted mechanically while insects primarily transmit the other viruses.

[carolyn137]

Doubting,
Many viruses and bacteria live in a dormant stage that only becomes active when it is introduced into the proper environment. The best example is tetanus. Tetanus spores are virtually everywhere in the soil.

*****

The vegetative form of C. tetanus does not live in a dormant form, but yes, the spores can and do as well as C.botulinum and several other spore formers.

But that situation is , to me at least, quite different from the vegetative forms of many human and plant pathogens that only infect with their vegetative forms b'c they don't have spore forms and thus can't remain dormant although several of the plant pathogens do, such as the fungal foliage pathogens that do have dormant spore forms.

This is fun b'c I spent most of my professional career teaching med students infectious diseases and rarely do I get the chance to be involved with such areas, so thanks for the opportunity.

And thanks also for the NCSU blurb which does say that TMV is somewhat unique in being able to remain dormant.

But back to the original issue of TMV and I still maintain that these days CMV is by far more prevalent than is TMV.

[Lee]

One thing I find interesting in the NCSU article is the comment
that it can remain dormant for a number of years, yet one of
the rememdies for the problem is crop rotation. It would seem
to me, that if TMV can lie dormant for 10+years, that crop
rotation wouldn't help, at least not any reasonable time framed rotation of crops.....

Lee

[tlcmd]

Carolyn,
I do concur, but TMV, although now not prominently seen, is out there waiting and still considered a significant threat (per many reliable University Agricultural Institutions including one nearer to you, Cornell. I read one research paper which even showed TMV to be in the water of the Danube river.

The curent worst viral threat to tomatoes in most areas in Southern US is TSWV since there are very few varieties which are resistant and virtually no heirlooms are. If you are fortunate to live in an area where you haven't TSWV, consider yourself lucky.

Fortunately, our seed companies and agricultural institutions are developing vegetables and other plants which are resistant to TSVW, CMV, etc.

Where did you teach? I graduated in 1967 from UNC School of Medicine and although retired, have maintained my CME's, etc. and have finally found time to delve into my "garden problems" and diseases. And as an internist, the diagnosis and treatment of diseases in plants as well as people is an enjoyable challenge.

Although this question to you may be akin to carrying coals to Newcastle, have you read Hans Zinser's "Rats, Lice, and History?" If not, it is a fascinating read and expands anyone's view of history and how diseases, especially typhus, changed the course of history many times.

Likewise this discussion is fun for me because I enjoy a lively civilized discussion of any sort. But, be warned, I've ADD and tend to meander. And it expands my knowledge base. Five years ago, I flat didn't know anything about garden pests and diseases and left it up to the toads and my resident black snake to guard the garden. Over the past few years, this forum and other groups have helped me to improve my efforts and technics in gardening. This year I'm very aggressively using what I have and am learning to utilized a variety of methods to help my toads and snake to keep the pests and diseases away.

Harmmmmoniously (I'm also a barbershop singer),

[Lee]

Dick,

Another intersting point is that in the past 4~5 years of growing tomatoes, including many heirlooms, my dad has only lost 2~3 to what I figured was
Tomato Spotted Wilt Virus.
Now whether it's luck, the abundant tree protection from thrips blowing in, or
the 80~100 rose bushes that are more attractive to thrips than tomato blossoms I don't know. I'm just amazed at his 9'+ plants out producing mine,
even though they are from the same seed stock (mine), and mine get 5 hours more of sun per day than his!
Must be in the soil...

And he also lives in Greensboro.....

Let me know if you're interested in adding CMV to this discussion as that is the
disease of the year in my new garden..... stinkin' aphids!

Lee

[carolyn137]

Since you asked a few personal questions publicaly I'll answer publicaly.

I graduated from Cornell then went to the U. of Rochester School of Medicine where I got a Ph.D in Microbiology with a concentration in infectious diseases.

I did a post doc in Rochester and taught med students there then moved to Denver to the U of Colorado Med School and taught and did research there there for quite a few years before moving back East to take care of ailing parents.

I then started teaching at a private liberal arts college in Albany since there was a lame duck Chair at the Med School in Albany in Micro and so no new faculty were being hired.

I retired in 1999 due to mobility problems re two bad hips. For a good reason I didn't get the hips replaced and in Dec of 2004 I fell and severed all four quads in the right leg. Three of the 4 returned to function but ther VMO did not which means that the knee swoops and buckles and that's why I still use a walker. A new left hip was put in in 2006 and a new right one in 2007 but I'm still in the walker.

So all my extensive growing has come to a halt, that meant that pre fall I was growing several hundreds of tomatoes each year with up to 150 varieties, and someone else does it all for me now, all here at home with a paultry 25 plants this year. I've recently landscaped the one acre around the house of the 30 acres I have here. I furnish the garden design and the money; that's my role.

But tonight, for instance, I was watching tennis, one of my prime passions, and every few days there are fresh bouquets on the coffee table and elsewhere ( Freda, who does my gardening as well as house cleaning brings them in for me) and the smell of the roses and Oriental lilies was just superb tonight.

And as regards tomatoes, I know many of the Cornell folks very well and actually with the Cornell Coop Ext did a disease survey of the hybrid and OP varieties I was growing that summer, about 150 varieties.

I was raised on a farm and at age 69 have been up close and personal with veggie growing for maybe 60 of those 69 years. My maternal grandparents had the largest nursery in the Tri city area for many years and working there summers is where I learned so much about flowers, which, to be honest are my first passion, especially the fragrant ones and I've hybridized both roses and daylilies.

And yes I've read Zinser's book and many more in the infectious disease area.

So that's me.

[feldon30]

I'm just glad I was able to slink away out of this discussion. *sneak*