Whole Leaf Tobacco

Tobacco Etch Virus (TEV)

deluxestogie

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#1
There are a number of viruses that affect tobacco, and most also can infect or be transmitted from other members of the solanaciae family (potatoes, tomatoes, eggplant, peppers).

Details of the pathophysiology of these virus infections are not particularly useful for the home grower. In this discussion of tobacco etch virus (TEV), I will focus on:

  • what does it look like?
  • where does it come from?
  • how does it spread?
  • how big a problem is it?
  • what should I do about it?

What does it look like?

Initially, the etching tends to occur along the veins.


Here, you can appreciate the fine, curlycue etching pattern. Affected areas are lighter in color.


You can see the tiny necrotic areas that eventually become holes.

Where does it come from?
In the typical home tobacco garden, a TEV infection is likely to come from nursery plants (yours or your neighbors') that are already infected. These can include, among others, tomatoes, potatoes, eggplant and peppers of every variety. Visible symptoms appear about a week after infection.

How does it spread?
TEV is carried to your tobacco by flying aphids (rather than by those that colonize a plant later on). It would seem that an insecticide might prevent such transmission, but studies have shown that transmission occurs within seconds of the flying aphid landing on the plant, and that preventive insecticide use had little impact on initial infection or on subsequent spread.

UC Pest Management Guidelines. Tomato Mosaic Diseases Caused by Potyviruses said:
Pathogen: Tobacco etch virus and Potato Y virus in the potyvirus group

The tomato potyviruses are transmitted plant-to-plant by many species of aphids. Aphids only retain the ability to transmit these viruses for very short periods of time (minutes to a few hours). Thus, spread is often very rapid and localized. In general, spread of tomato potyviruses in the field occurs when aphid activity in fields is high. The type of aphid activity that promotes virus spread occurs when aphids actively move through the crop, not when they colonize plants.

http://www.ipm.ucdavis.edu/PMG/r783102611.html
McDonald SA:Epidemiology said:
...secondary spread within the field was significant in the epidemiology of this virus.

...Scotch Bonnet plants can become infected with TEV for about one week before developing symptoms.

An older infected pepper field located about 80 m to the left of this field was likely to have been the original source of the virus.

[Toward the end of the growing season] the proportion of TEV infected plants ranged from 20 to 60%.

http://scholar.lib.vt.edu/theses/available/etd-03212001-144228/unrestricted/CHAPTER_3.pdf
How big a problem is it?
TEV will not infect humans. If you are growing cigar wrapper, then TEV can damage the integrity of the leaf enough for it to be useless as a wrapper or binder. For cigar filler, or for cigarettes, cut tobacco and other uses, the major impact of TEV is reduced quality and productivity. A significant issue is that leaves with many tiny holes, whether from TEV or flea beetles, tend to be difficult to color cure. Very young transplants may be killed. (For fruiting plants, such as tomatoes, potatoes, eggplant and peppers, TEV can cause deformed fruit and rotted tubers.)

What should I do about it?
If you run a Google search on "tobacco etch virus management," you will find little of any value. Agricultural Extension Services tend to simply recommend planting resistant varieties (of which there are few).

I have a single plant (Wisconsin Seedleaf, shown in the photos above) that appears to have tobacco etch virus. It is fairly full, and about 2.5' high. None of the surrounding plants appear to be affected. My temptation was to allow it to grow, to see how it progressed, and whether or not it spread. I understood that it was spread by aphids, even though I haven't seen a single aphid yet this year.

I asked BigBonner, and this was his reply:

BigBonner said:
I personally would remove it from other tobacco plants . I would also get rid of the soil and tray it was grown in .

Take a good look at any plants you may have bought from stores to see if they have the TEV . I believe it had to come from somewhere and did not come from the seeds .Maybe a neighbor who bought tomato plants .

I know of farmers here who get these types of viruses and disease in their float trays . Like root rot , the only way to get rid of it is to buy new float trays . It can be cured with Terramaster to make new root growth .But to prevent any disease from making your soil a breeding ground I would destroy it first .

Black shank is one that stays in the soil and needs tobacco to live on .

I remember back 30 years ago that farmers called what I think is TEV , rust .

As far as spreading , I'm not sure , I just know I wouldn't take a chance on it making my crop ground a new home . From what I have read It also over winters .
The TEV plants I have seen in a few fields here did not spread . I don't know why but I never seem to have any disease problems except back in the early 90's we had blue mold so bad . ....

I believe I would remove the plant and count my loss . In the long run it may be a big gain . No hole in the cigar leaf would be the gain .

Here is a link to RJ tobacco diseases http://www.invasive.org/browse/autimages.cfm?aut=2887
I promptly went out and lopped off the affected plant at the ground, then removed the root ball, dirt and all. Since the latent period seems to be about 1 week, I'll know in one week if I have other plants with TEV.

Bob
 

Chicken

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#2
ive got some of that in my plot also,

tomorrow, i guess i got about 6 plants to get rid of,

oh well i got 6 seedlings to take up that space,

ive been thinking of removing them,

NOW THEY ARE DEFINATLLY GETTING CUT DOWN, OR PULLED UP,
 

deluxestogie

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#3
I would carefully examine all of the other plants for early signs. If it's already widespread, then removing those 6 plants may not make any difference with the rest of the patch.

Bob
 

Kaneo

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#6
I know this is an old post but it looks like I have something similar in one of my V Gold, I have isolated this plant for now but I'm thinking I should cull it.

 

Knucklehead

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#7
Bummer Kaneo. That sure looks like the pictures Bob posted. Take it out root ball and all. Burn it.
 

FmGrowit

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#8
When you finish removing the plant, be sure to clean everything you used in the operation. Roasting your shovel head over an open fire would be fitting for this time of year also.
 

marksctm

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#9
As a rule, even if not infected, good healthy crops, is it best to remove roots from the ground at the end of the season, or can they be left in the ground for the nutrients, or does it matter?

Thanks,
 

Kaneo

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#10
I'm probably lucky that this has shown up on a V Gold planted in a 20 litre bucket - this was how I was able to isolate it. I have now dumped the plant, bucket and potting mix - we have a 200ltr wheelie bin for rubbish that gets collected once a week so the whole lot has gone in there.

I will continue to inspect the other plants for signs of this virus, thanks for the advice and posting the original thread
 

Knucklehead

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#11
As a rule, even if not infected, good healthy crops, is it best to remove roots from the ground at the end of the season, or can they be left in the ground for the nutrients, or does it matter?

Thanks,
I read somewhere you remove all tobacco matter after season to discourage disease and pests that might carry over to next season. I might have read it here or in an old book.
 

Boboro

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#12
Bummer Kaneo. That sure looks like the pictures Bob posted. Take it out root ball and all. Burn it.
Root balls are hard to burn I give mine to the garbage man. IM forced to pay $13 a month Or I cant buy a car tag. If I don't want it they gon'a get it. If you get a ticket for no tag an ant got no money while you in jail you can ride the garabge truck to pay off the fine.Freedom in MS. If you ride the truck.
 

Knucklehead

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#13
Root balls are hard to burn I give mine to the garbage man. IM forced to pay $13 a month Or I cant buy a car tag. If I don't want it they gon'a get it. If you get a ticket for no tag an ant got no money while you in jail you can ride the garabge truck to pay off the fine.Freedom in MS. If you ride the truck.
Did anybody ever point at you and say "look at that somebody threw away a perfectly good redneck!"?
 

deluxestogie

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#16
I'm having difficulty getting that pdf file to download, so I haven't seen the photos.

Many tobacco diseases and deficiencies present with subtle leaf signs that are difficult to tell from one another at a single moment in time. By contrast, the onset and initial distribution of an abnormality, as well as its pattern of spread through standing tobacco can give clues.

Generally, if an isolated plant displays an abnormality initially, then with the progression of time it appears to spread to other plants (contiguous plants with natural spread; just about anywhere if spread by your hands or tools), a pest of some sort (viral, bacterial, fungal, etc.) is more likely.

If an entire swath of plants shows the initial signs, then a nutrient problem (excess, deficiency) or toxin (e.g. herbicide drift) becomes more likely.

Another helpful approach is to observe the progression of abnormalities in a single plant. Most of the tobacco disease photo albums will illustrate a particular disease with multiple photos taken at various stages of disease.

Bob
 

Fisherman

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#17
Mr Deluxe,

We need a post that has loads of pics on nutrient defeciencies and overdoses and diseases.

I spent 3 days now looking for pics of these and mainly get the same. There are some on the pay for veiw channels that most likely contain lots of text and no pics.
I found out some fertilizer is radioactive but wont go into that now :)

Maybe if more members would post picts of their problem plants we could concur on the problem. Instead I read "My plant is glowing green" and no pic...... Sheesh we have a hard time visualizing "green" as it is.

ANd you are right.... a progression and more information is needed to isolate the cause as well.

Being a first time grower as well , I am fussing over stuff that may not be important and maybe missing stuff that is.

Mike
 

deluxestogie

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#19
Fisherman said:
We need a post...
Feel free to start a thread for that topic, but keep in mind that many photos found on-line are covered by copyright. Links to helpful image sites are more appropriate than swiping large quantities of images by copy-and-paste. If you use someone else's image, include an attribution reference and link. Better yet, only use your own photos.

Lots of images (over 1300), but poorly organized:
http://www.forestryimages.org/search/action.cfm?q=tobacco

Well organized by disease name (same as Knucklehead's link):
http://www.ipmimages.org/browse/Areasubs.cfm?area=62

Bob
 
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