How to deal with gall on an important seedling

A meeting place for rose breeders.
Judith Singer
Posts: 706
Joined: Wed Dec 31, 1969 7:00 pm
Contact:

How to deal with gall on an important seedling

Post: # 64985Post Judith Singer
Mon Feb 06, 2017 1:19 pm

I have what looks like crown gall on an important 3 year old seedling I've been watching :(

I know the bacterial dna can enter the distant tissues of the plant but does it always? I have many cuttings that have rooted and I'm wondering if I watch these for some time period, and they don't develop any galls, can I assume the new plants are clean? Has anyone used Actinovate? Gallex, Bacticin? It would be very easy to treat the small cuttings if that would help. All opinions and ideas welcomed!

jturner
Posts: 196
Joined: Wed Dec 21, 2011 6:12 pm
Contact:

Re: How to deal with gall on an important seedling

Post: # 64986Post jturner
Mon Feb 06, 2017 3:44 pm

Judith Singer wrote:I have what looks like crown gall on an important 3 year old seedling I've been watching :(

I know the bacterial dna can enter the distant tissues of the plant but does it always? I have many cuttings that have rooted and I'm wondering if I watch these for some time period, and they don't develop any galls, can I assume the new plants are clean? Has anyone used Actinovate? Gallex, Bacticin? It would be very easy to treat the small cuttings if that would help. All opinions and ideas welcomed!
Hot water treatment of grape vine cuttings has been fairly successful for eliminating crown gall from the cuttings, see, for example,
http://www.ajevonline.org/content/41/4/325.short
"After one season's growth, less than 2% of the hot-water-treated, grafted vines showed crown gall symptoms. In contrast, up to 60% of untreated control vines were galled."

This treatment has also been somewhat successful for cherry and plum seedlings. Cherries and plums are members of the rose family. I don't know whether anyone has tried it with roses, but I'd try it, if I had an important seedling that was infected. Good luck!
Jim / Monterey Bay, California / USDA zone 9b / Sunset zone 17

Kevin Brownlee
Posts: 100
Joined: Wed May 09, 2012 7:32 pm
Contact:

Re: How to deal with gall on an important seedling

Post: # 64987Post Kevin Brownlee
Tue Feb 07, 2017 11:42 am

Judith - In my case, the gall was above ground. I cut off the affected cane and hoped for the best. That was over five years ago and it hasn't reappeared. The plant is as healthy as ever. Everyone's experience seems to be different.

Judith Singer
Posts: 706
Joined: Wed Dec 31, 1969 7:00 pm
Contact:

Re: How to deal with gall on an important seedling

Post: # 64988Post Judith Singer
Tue Feb 07, 2017 12:59 pm

I have just tried the heat method and we'll see how it works. There's so much confusing information about crown gall, it's hard to determine what is actually going on.

My seedlings get put up in the desert and it gets up to 140 degrees up there - I wonder if that would work too? Maybe put the cuttings in a plastic bag for 1/2 hour-1 hour. If they don't get fried, it might work. Heat treatment is supposed to work for rose mosaic virus as well.

Judith Singer
Posts: 706
Joined: Wed Dec 31, 1969 7:00 pm
Contact:

Re: How to deal with gall on an important seedling

Post: # 65050Post Judith Singer
Wed Feb 22, 2017 9:26 am

Update on the gall heat treatment - I treated the 6 sample cuttings (which had already calloused) with hot water for 1/2 hour. I didn't have a thermometer yet, so I heated the water to 'hot' but not so hot I couldn't keep my hand in it. I would imagine it was at least 50 C or 122 F. After treatment, I put the cuttings back in the damp newspaper. The next day, I opened the paper to find the callous' had turned brown but the rest of the cuttings looked fine. Of the 6 samples, I re-cut 2 of them to the next bud node. This morning I checked the cuttings and 2 from the brown calloused ones have sent out roots just above the callous! I am thrilled!

You guys have saved my seedling! I will watch it for a few years to make sure there are no galls forming, but I'm very excited to hear about this treatment method! I have now received the thermometer, and will heat up some water to estimate how hot the test water was. Will let you know.

Judith

Judith Singer
Posts: 706
Joined: Wed Dec 31, 1969 7:00 pm
Contact:

Re: How to deal with gall on an important seedling

Post: # 65067Post Judith Singer
Fri Feb 24, 2017 8:59 am

Well, this is an unexpected consequence of this hot-water experiment. ALL of the cuttings rooted, both the ones whose callous turned brown from the treatment, and the ones I re-cut to the next node after the hot-water tx. That doesn't usually happen for me. Could it be that the heat treatment stimulated root formation? Interesting. I measured the temperature of the water and I would estimate it to be around 122-124, so we're good!

I think another experiment is in order.

Judith

roseseek
Posts: 4795
Joined: Sun Dec 11, 2011 6:54 pm
Location: Zone 9b Central California, Sunset Zone 15
Contact:

Re: How to deal with gall on an important seedling

Post: # 65073Post roseseek
Sat Feb 25, 2017 12:00 am

Good catch, Judith! This may be a remarkable discovery! I can't wait to hear your findings!
Kim
California Central Coast
USDA Zone 9b
Sunset Zone 15
Cooler inland coastal valley with strong marine influence

jturner
Posts: 196
Joined: Wed Dec 21, 2011 6:12 pm
Contact:

Re: How to deal with gall on an important seedling

Post: # 65075Post jturner
Sat Feb 25, 2017 10:09 am

Judith Singer wrote:Well, this is an unexpected consequence of this hot-water experiment. ALL of the cuttings rooted, both the ones whose callous turned brown from the treatment, and the ones I re-cut to the next node after the hot-water tx. That doesn't usually happen for me. Could it be that the heat treatment stimulated root formation? Interesting. I measured the temperature of the water and I would estimate it to be around 122-124, so we're good!

I think another experiment is in order.

Judith
Fascinating! I look forward to hearing the results of your experiment.
Jim / Monterey Bay, California / USDA zone 9b / Sunset zone 17

Post Reply

Who is online

Users browsing this forum: Bing [Bot] and 2 guests