blatta

I was disappointed to find one of my Musa 'chini champa' is showing all the usual symptoms of Banana Bunchy Top Virus (BBTV).
I uploaded some photos of the plant:
Leaf emerging which is considerably smaller than the last, and pale and deformed:

dark green streaks on underside of midrib (easier to see on younger leaf which is not yet waxy:

Underside of leaf, sowing the dark streaks running along the midrib, as well as dark 'J hooks' running from the leaf:


The plant above is now in a sealed tub and will be incinerated later.

I have a few other chini champas from the same 'batch', which are not yet showing symptoms (some are showing a little Banana streak virus, but that can be expected with AB types)
Can plants survive with BBTV without showing symptoms?
-How long will I have to wait until I'm sure they're free?
Also, does BBTV affect other species?

Luckily I rarely get aphids, so it should not have spread to anything else, and, when possible, I keep new plants in quarantine so they can be carefully monitored.

Thanks,

Andrew

kcj1219

How old is the plant and when was it potted? Just asking cause its normal when you pull a plant out of dormancy and repot it that it might do some weird things until the roots take hold and will eventually push out normal leaves.

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KJ

raygrogan

Looks like BBTV to me. Don't know about the "how long" etc. questions. You are wise to quarantine / burn that guy, BBTV is a total pain. And I would watch everything from that source. Having said all that, people have learned to live with BBTV, basically keeping tools clean and rogueing out any that show symptoms. At least with the more resistant types like tall apple. Good luck and hope your bananas don't get it.

Gabe15

Where are you located and where did you get the plant from? Is it a new plant you acquired?

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Growing bananas in Colorado, Washington, Hawaii since 2004. Commercial banana farmer, 200+ varieties.

blatta

Thanks for the replies,

It is a new plant, bought as a dormant corm. It was almost certainly imported from India.

I'm in the UK, so its very unlikely to have been infected locally.

Is bunchy top only spread by the aphid, Pentalonia nigronervosa? As in the aphid has quite a specific role, not just dirty mouthparts. The very few aphids I get tend to be small pink ones that sometime feed on seedlings, especially Musa dasycarpa, and sometimes green ones on larger plants which never manage to establish.

Can the virus survive outside the plants for long? I always take care not to use the same tools for many bananas, especially new ones.

raygrogan

[IMG][Banana Gallery - Banana_aphids_visible_vulnerable_in_transition_to_newest_leaf_-_first_seen_ http://www.bananas.org/gallery/water...&filefix=.jpg]

(credit [Bananas.org - View Profile: raygrogan raygrogan])[/IMG]

My knowledge of the aphids is limited - I look but just hardly ever see them, and haven't studied other sources. In my limited experience they are so stealthy I would not say a banana plant did not have them just by looking at it.

But if you are pretty sure you don't have the aphids, and don't use tools between plants, and got that BBTV one sealed up as soon as you saw it, chances are that the rest of the plants are OK. In two Honolulu banana patches I keep up with we see BBTV infected plants right next to the rest of the healthy ones fairly regularly. As long as the BBTV one is taken care of, it does not seem like it spreads. We assume the next case (sometimes 6 mos later in a completely different part of the patch) is another random infection from some other source. (In Honolulu the sources are out there. Sometimes like looking over a fence I see a huge clump where virtually all the plants have BBTV, just sitting there do-dee-do, apparently the owner has no clue. It doesn't kill the plants, at least for a long long time. Just tiny little plants that never grow over 2 feet.)

Good luck, hope UK does not become infected.

Gabe15

You've done the right thing by destroying the plant. People are always requesting plants from me in Hawaii, and I tell them of the risk of sending bunchy top, and you can see how easy it is.

Yes they can. For most varieties, there is a latency period where the plants have the virus but do not show symptoms. This can range from a few weeks to several years depending on the variety and conditions. There are a few known varieties that can have the virus but never show symptoms, or show symptoms at very low rates, but they need some more testing. The varieties that are infected that do not show symptoms can still act a virus source for clean aphids to pick up the virus and spread it to clean plants.

If the plants looks clean, and you imported them from a known BBTV infected region, such as India, you can't ever be too sure without some laboratory tests. The most important thing is to make sure that there are no Pentalonia aphids coming in on the plant. Even with a good cleaning, the aphids can easily sneak by as they can hide deep in the pseudostem sheaths.

I recommend that the pseudostems be cut below the crown to eliminate the petiole hiding places, and the outer two pseudostem sheaths be pulled back to the corm and removed, and then the whole plant sprayed down with a soapy water and alcohol solution. The aphids are the only way the virus can spread from plant to plant so if you eliminate them, and the plant has the virus, it cannot be spread to other plants.

The Banana aphids themselves are usually easy to ID among other common aphids. They are black with white stripes on their legs.

Some studies are underway to determine if the virus can survive in non-banana plant hosts, but it has already been determined that the banana aphids almost exclusively feed on banana plants. Previously is was thought that they also feed on gingers, heliconia and taro, but it has been found that those aphids are actually a different, but very closely related species and they rarely feed on banana plants.

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Growing bananas in Colorado, Washington, Hawaii since 2004. Commercial banana farmer, 200+ varieties.

Gabe15

Yes. There is no evidence is is spread between plants by anything thing else, including other aphids or tools.

The virus can be detected outside of the plant, such as in ground water, but it cannot infect plants without being in a banana aphid that then feeds on a banana plant. It is not spread by tools like some other plant viruses are.

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Growing bananas in Colorado, Washington, Hawaii since 2004. Commercial banana farmer, 200+ varieties.

blatta

Thanks, I really appreciate the info.

I am sure the plants, as well as all my others are Pentalonia nigronervosa free- They were from corms which were cut right back, and most of my others are grown from seed.

I spend far too much of my time looking at insects, i'd be surprided if theyre there. It is encouraging to know that the aphid is pretty much essential, but also annoying that i cant be sure the others are virus free.

I dont suppose anyone knows how Musa (AB) 'chini-champa' responds to the virus? What conditions encourage the symptoms to develop faster?

raygrogan

Gabe, thanks for the bit about tools not spreading BBTV. That matches experience in the two patches I keep up with. In my own I go nuts trying to clean tools between plants, etc. My friend just rogues out the BBTV plants with the same pry bar he uses to thin keiki, whacks here and there with his machete, etc. But he gets no more BBTV than I do, just the random one every so often.

Blatta, I think you're doing everything right and will end up BBTV free. There is one more step you could take between now and the forever to watch the original Chini. I think (just from a few times testing myself, the pros say this is wrong sometimes) if you wait until there is a reasonable-sized pup, and then destroy the mother plant by injecting straight glyphosate deep into the stem, you can reduce the odds of BBTV at least somewhat.