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Author Topic: citrus greening - my own experiment with thermal therapy  (Read 2653 times)

Lory

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citrus greening - my own experiment with thermal therapy
« on: April 20, 2018, 10:34:59 PM »
I've a 4 years old pomelo seedling which is unfortunatly affected by citrus greening since late 2016.
It's a beautiful tree, uncommonly nicely shaped with a round canopy unlike many seedlings which tends to have an upright and unattractive shape.
The main trunk and branches have huge thorns but the youngest branches produced in the past 2 years are thornless.





Growth in the last year hase been absolutely lacking because of the HLB disease.
After reading several articles i took the decision to try my own experiment with thermal therapy.
It's not easy since the three is quite big already (about 3m 9ft) and i haven't a PET film big enough to cover it thoroughly.
I used 3 PET bags the big ones normally used for protecting ceramic tiles pallets (a freind of mine sent me these)








I put a thermo-higrometer inside the canopy to monitor temperature and humidity.
I'm confident to reach the therapeutical temperatures of about  45-50 C (115-125 F) since sun now  is extremely strong here and inside i measured a temperature of about 34C ( 93F) at  just 8 am.




I will try to control the temperature with the opening in the bottom of the bags.
I'm planning to let the heat work for 5-6 days then i'll remove the bags, i'll prune water and fertilize and see wether i'll have some improvement  or not .
Updates to follow!





Lorenzo

Millet

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Re: citrus greening - my own experiment with thermal therapy
« Reply #1 on: April 20, 2018, 11:00:47 PM »
I'm not an expert on thermal therapy, but from the pictures that I've seen, the foliage, trunk and some of the ground around the tree are completely covered.  If all parts of the tree needs to be covered and heated I'm not sure. Anyway, I wish the very best  future for your pummelo.
« Last Edit: April 21, 2018, 12:02:46 PM by Millet »

Lory

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Re: citrus greening - my own experiment with thermal therapy
« Reply #2 on: April 20, 2018, 11:59:52 PM »
thank you Millet!
Actually as i've read in academic studies, bactery is present everywhere even in trunk and roots.
I was even planning to wrap the main trunk in a black PET film to heat it enough to have bacterial burden reduced.
Anyway, because of the thermal stress on foliage,  bactery tends to migrate from roots to canopy and this results in a reduced baterial overall load  especially with multiple thermal tratments repeated every year or so.
here's some of the bibliography i was getting info from:

https://citrusrdf.org/thermal-therapy-for-citrus-trees-affected-by-huanglongbing-hlb

https://www.sciencedirect.com/science/article/pii/S2095311915610851

https://www.nature.com/articles/hortres201754
Lorenzo

Radoslav

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Re: citrus greening - my own experiment with thermal therapy
« Reply #3 on: April 21, 2018, 03:57:02 AM »
Interesting, if it works.
So, in greenhouse, it should be easy to exterminate the diseases. In my greenhouse, zone 6, it is not a problem to reach  45-50 C during sunny day, even in the spring. In summer, if I close the door and window, 60C can be reached easy.

Lory

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Re: citrus greening - my own experiment with thermal therapy
« Reply #4 on: April 22, 2018, 07:58:50 AM »
Exactly.
The difficult is to find the balance between a good therapeutic effect and a moderate heat damage.
In greenhouse for sure much easier than I'm trying to do in open field.
Lorenzo

Luisport

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Re: citrus greening - my own experiment with thermal therapy
« Reply #5 on: April 22, 2018, 08:26:00 AM »
Exactly.
The difficult is to find the balance between a good therapeutic effect and a moderate heat damage.
In greenhouse for sure much easier than I'm trying to do in open field.
Good luck my friend, it seams a great tecnique!  ;D

Lory

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Re: citrus greening - my own experiment with thermal therapy
« Reply #6 on: April 23, 2018, 10:08:43 AM »
I removed today the PET bags.
Unsurprisingy some damage happened in the upper portion of the tree, part of the foliage got literally steamed.
I measured temperatures of about  42C (110F) in the lower parts of the canopy, probably in the upper portions temperatures climbed to 45-48 C (115-118F) so it's normal.
I pruned the tree quite heavily reducing the canopy size of about 30%
Then i drenched the tree with several pails of rain water and soluble fertilizer N-P-K  20-5-30 + chelated microelements.
Here now is full summer very hot and dry.
Pictures and updates to follow.


Lorenzo

Millet

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Re: citrus greening - my own experiment with thermal therapy
« Reply #7 on: April 23, 2018, 12:06:11 PM »
Interesting experiment.  Looking forward to results.

Lory

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Re: citrus greening - my own experiment with thermal therapy
« Reply #8 on: April 24, 2018, 03:14:40 AM »
This is the temperatures the system reached during the 4 days of treatment under scorchy summer sun.
To Notice it was just 11 am.
Thermometer was placed in the lower portion of the tree so very likely in the upper portion they were several degrees higher



And this is how the upper branches tips appeared at time of bag removal: STEAMED by heat




This is how i pruned the tree. About 30% of the canopy has gone.
Now it's looking really awful hopefully it will  flush within some weeks, updates to follow




Lorenzo

Millet

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Re: citrus greening - my own experiment with thermal therapy
« Reply #9 on: April 24, 2018, 05:39:07 PM »
Presently, the only way to prevent a citrus tree from ever being inflicted with Greening (HLB), is to build a screen enclosure around the tree to prevent the Asian psyllid from feeding upon the tree.

Lory

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Re: citrus greening - my own experiment with thermal therapy
« Reply #10 on: April 24, 2018, 10:23:26 PM »
Exactly.
I can do for my small clementine and femminello zagara bianca lemon because they are still potted and of manageable size.
But the ponderosa lemon and the 3 pomelos (1 seedlings 3 grafted )are in the ground and too big to be enclosed in a screen
Lorenzo

Millet

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Re: citrus greening - my own experiment with thermal therapy
« Reply #11 on: April 24, 2018, 10:26:18 PM »
Greenhouse then?

Lory

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Re: citrus greening - my own experiment with thermal therapy
« Reply #12 on: April 25, 2018, 08:08:29 AM »
unfortunatley the tree planted in the ground are far from each other so i would need several greenhouses to enclose them all.
Moreover temperatures are constantly high here, it would be a severe challenge to keep acceptably cool inside.
As for now all my trees in the ground are (sigh) unprotected.
I noticed several pomelos affected with greening here in the philippines.
In most cases, non professional growers are absolutely unaware of the disease and its gravity.
Anyway, for some unknown reason (maybe the scorching sun?) noone of the affected trees was severely crippled by the HLB.
Some leaf yellowing, scarce foliage and fruiting and reduced vigour but nothing apocaliptic as i've seen browsing pictures of citrus greening worldwide
Lorenzo

Radoslav

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Re: citrus greening - my own experiment with thermal therapy
« Reply #13 on: April 25, 2018, 11:29:05 AM »
unfortunatley the tree planted in the ground are far from each other so i would need several greenhouses to enclose them all.
Moreover temperatures are constantly high here, it would be a severe challenge to keep acceptably cool inside.
As for now all my trees in the ground are (sigh) unprotected.
I noticed several pomelos affected with greening here in the philippines.
In most cases, non professional growers are absolutely unaware of the disease and its gravity.
Anyway, for some unknown reason (maybe the scorching sun?) noone of the affected trees was severely crippled by the HLB.
Some leaf yellowing, scarce foliage and fruiting and reduced vigour but nothing apocaliptic as i've seen browsing pictures of citrus greening worldwide
I read on web, that according to experiences from Vietnam, pomelo is quite tolerant to greening, it suffers damage, but can survive.

Lory

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Re: citrus greening - my own experiment with thermal therapy
« Reply #14 on: April 25, 2018, 11:34:07 PM »
Ah that's why. this could be a reason.
Also calamondin is prone to greening here and affected trees usually look very ugly
Lorenzo

Lory

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Re: citrus greening - my own experiment with thermal therapy
« Reply #15 on: April 29, 2018, 09:18:24 PM »
Update number 1:
Exactly 10 days after removal of plastic cover some buds appeared.
Probably  the combined effect of heavy pruning, watering/fertilizing and hopefully some health improvement caused by the thermal therapy.
Now I'm a bit more confident, for some days I thought i had killed my tree by steaming  ;D

The top of the tree is still "dormant" probably the very high temperatures hit hard here:




The lower portion looks more active










Let's see what happens in the next weeks, more updates to follow
Lorenzo

Millet

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Re: citrus greening - my own experiment with thermal therapy
« Reply #16 on: April 30, 2018, 04:22:22 PM »
Lory your idea is being used in Florida

Florida Company Says They Have Beaten Citrus Greening
http://www.freshplaza.com/article/193658/Florida-company-says-Weve-beaten-citrus-greening

Lory

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Re: citrus greening - my own experiment with thermal therapy
« Reply #17 on: May 01, 2018, 02:48:49 AM »
But this is a bit different.
It looks more of a protective screen to PREVENT young trees to be infected by the HLB.
Thermal therapy is meant  to cure trees which have already been infected
Lorenzo

Lory

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Re: citrus greening - my own experiment with thermal therapy
« Reply #18 on: May 11, 2018, 10:34:36 PM »
UPDATE #2:

20 days after be PET bag removal.















Flushing is really powerful, new shoots are already 20cm (8 inches long) and they're growing fast.
Interestingly they look EVENLY GREEN (thought not deep green being still young) and don't exhibit any sign of HLB.
To be noticed that this tree had very very limited and stunted growth during the past 12 months despite i tried many times to boost its energy with watering, pruning and fertilization.
Until now my experience with thermal therapy is very positive, let's see the future evolution, more updates to follow.

« Last Edit: May 14, 2018, 10:01:08 AM by Lory »
Lorenzo

Millet

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Re: citrus greening - my own experiment with thermal therapy
« Reply #19 on: May 14, 2018, 12:30:13 PM »
The tree looks very good, watch for the future of the tree.  From what I understand heat does not completely cure the HLB but does set the disease back.

Lory

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Re: citrus greening - my own experiment with thermal therapy
« Reply #20 on: May 14, 2018, 09:43:24 PM »
Yes you are right.
The disease is not defeated.
But the high temperature has a similar effect on bactery as fever in human body.
Reducing damatically the bacterial titer (concentration) in vegetative area boosts tree energy pushing  it to flush.
According to bibliography the effect is just temporary lasting for about 24 months.
Better than nothing, before the treatment the tree has been "paralyzed" for more than one year....
Lorenzo

dudu12

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Re: citrus greening - my own experiment with thermal therapy
« Reply #21 on: June 07, 2018, 10:41:26 AM »
amazing! following

countryboy1981

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Re: citrus greening - my own experiment with thermal therapy
« Reply #22 on: June 07, 2018, 11:25:36 AM »
Yes you are right.
The disease is not defeated.
But the high temperature has a similar effect on bactery as fever in human body.
Reducing damatically the bacterial titer (concentration) in vegetative area boosts tree energy pushing  it to flush.
According to bibliography the effect is just temporary lasting for about 24 months.
Better than nothing, before the treatment the tree has been "paralyzed" for more than one year....

The question is, if you do it again in another 24 months will it get the tree back in shape again for another 24 months?  Additionally, what about the roots that are affected by HLB, does it reduce the bacteria in the roots so the roots can rejuvenate?

Lory

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Re: citrus greening - my own experiment with thermal therapy
« Reply #23 on: June 08, 2018, 05:50:07 AM »
As i read the treatment can/should be repeated after 24/36 months to rejuvenate the tree again.
And it was stated that bacteria tend to migrate from the root system to the canopee thus being killed by thermal therapy.
In general the overall concentration, "amount" of live bacteria in the tree is greatly reduced.
More update to follow, the new vegetation of my tree is now hardening and getting a nice deep green color  :)
Let's see what will happen next....
Lorenzo

Tom

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Re: citrus greening - my own experiment with thermal therapy
« Reply #24 on: June 09, 2018, 10:14:36 AM »
Excellent work Lory, sounds very promising. Green house growers in high risk situations should be especially encouraged. Thank you for all the time spent and for keeping us in the loop ! Tom

 

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