Tropical Fruit Forum - International Tropical Fruit Growers



Author Topic: Mango graft problem  (Read 604 times)

HIfarm

  • Hero Member
  • *****
  • Posts: 1020
    • Paukaa, HI, USA zone 12b
    • View Profile
Mango graft problem
« on: August 21, 2018, 02:49:21 PM »
I have tried to graft some mangoes the last couple of years & have had very poor success.  I have been using cleft grafts & used to get very good results on temperate fruits, ornamentals, conifers, etc but I have not done well with mangoes.  I have been using rubber bands to secure the grafts and buddy tape to cover the scion & area near the graft.  It is possible that my eyesight is just gone down hill enough that I no longer line up the cambiums well enough but I don't think so. 

One thing I have noticed is that the scions tend to look like they are developing sooty mold (or something that resembles it).  Unfortunately, I neglected to take any pics.  It is not present on any of my trees or anything nearby but this is the Hilo area & fungus & other microbes are everywhere.  We do have a humid environment here but I am guessing that I still need something to insure that the graft area does not dry out initially.  I have not tried hydrogen peroxide or dilute bleach to sterilize the scions -- maybe that would be worthwhile.   Anyone encounter anything like this?  Any ideas?  I was thinking about trying to use a loose fitting plastic bag with a few small holes in it taped to protect the graft area from drying.

John


sapote

  • Sr. Member
  • ****
  • Posts: 499
    • USA, CA, Burbank, 10a
    • View Profile
Re: Mango graft problem
« Reply #1 on: August 21, 2018, 03:39:28 PM »
I think the sooty mold took over after the scion died and in the decaying process. What size of scion and rootstock in the cleft graft? Matching OD will give you better chance of max cambium contact. If you see water condensation into droplets inside the plastic wrap then it might be too much, then adjust the cover to control the moisture inside. I don't use rubber band (can't see anything wrong with it) and just  use plastic strip to tightly wrap the scion / rootstock together over the union, then cover the whole scion with a paper tube tailored for its shape.

simon_grow

  • Hero Member
  • *****
  • Posts: 4751
  • USA, San Diego, CA, Zone 10a
    • View Profile
Re: Mango graft problem
« Reply #2 on: August 21, 2018, 03:58:14 PM »
I sometimes spray and wash my scions with copper soap before I wrap them. I do this for scions That appears to have fungus on them or if itís even questionable.

Do you prep your scions by clipping the leaves 1-2 weeks before removing from the mother tree? If you prep your scions and your rootstocks are healthy and pushing growth, you should have good success rate.

Simon

HIfarm

  • Hero Member
  • *****
  • Posts: 1020
    • Paukaa, HI, USA zone 12b
    • View Profile
Re: Mango graft problem
« Reply #3 on: August 21, 2018, 04:18:18 PM »
Thanks, guys.  This is for scions I have purchased from the mainland (trying to introduce new varieties here) so I am not sure about the prep before harvest.  At least a couple scions looked like they had been trimmed of leaves in advance since small buds were swelling.  The trees never really go into any sort of dormant state here, just slow a bit in the winter.  When I grafted the batch this year, I had a ton of dormant buds quickly developing and pushing vigorously below the graft so the rootstocks were definitely doing their jobs.

Virtually every graft develops condensation under the buddy tape, this is why I was a bit concerned about this.  I am not sure about this year, but last year I am pretty sure that I had at least of couple of scions that started to swell buds but then were overtaken by the sooty mold and failed.  So, copper soap sounds like a better option than dilute bleach or peroxide to sterilize the scion?

The paper tube to shield the graft from sun is probably a good idea, I will give that a shot next time I try. 

I am still wondering if a perforated plastic baggy might work better than buddy tape here...

John

simon_grow

  • Hero Member
  • *****
  • Posts: 4751
  • USA, San Diego, CA, Zone 10a
    • View Profile
Re: Mango graft problem
« Reply #4 on: August 21, 2018, 04:45:07 PM »
I used to use bleach to sterilize my samples before extracting DNA but I felt Copper soap was safer for scions I wanted to keep alive. I get some condensation on most my grafted scions(probably all but havenít paid much attention) but it doesnít usually affect my rate of success because I stay on top of it.

The more dry your scions are before wrapping with buddy tape or parafilm, the less condensation you will have.

After I graft, I keep a close eye on my scions and rootstock. Grafting the scion to the rootstock is just the beginning. Here are some maintenance steps I take, post grafting, that helps with the success rate.

I place my grafts in intensive care for the first 1-2 weeks. If grafting in the field, I give the graft some shade. If grafting potted plants, move them to the shade or part sun.

Look for growth below the graft union and if you see any, remove them. Itís usually easier to let them grow to about 1/2 inch before removing. These growths take energy away from the scion.

If you see a lot of condensation under the parafilm or buddy tape, you can use a scalpel to puncture a hole in the film and air dry or blot dry. Depending on how long itís been since the graft, you can leave the hole there if you see the buds are about to push or you can patch the hole with buddytape or parafilm. If itís only a small amount of condensation and you cleaned the scions with copper soap, you shouldnít have to worry about slight condensation.

If thereís a lot of condensation, Iíll sometimes unwrap, dry and then re wrap but I only do this as a last resort because there is a high probability that you can dislodge the union.

If the buds donít push after about a month, you may want to redirect energy by removing apical dominance of nearby branches, especially branches directly off the branch you grafted.

I sometimes get very delayed pushes from my scions but it is usually because the scion was not prepped, the rootstock was weak or the temperatures were not optimal. Hereís a graft that took more than two months to push. It took so long because the rootstock was in bad shape and had not a single leaf.





Simon

sunworshiper

  • Oviedo, FL (9b)
  • Sr. Member
  • ****
  • Posts: 405
    • View Profile
Re: Mango graft problem
« Reply #5 on: August 21, 2018, 05:44:56 PM »
I've had better take rates when I wipe down the spot on the host tree with a captan solution and soak the scions in a captan solution for a minute or two before grafting. When I haven't done this I've seen a lot more fungal issues on the grafts.

lebmung

  • Sr. Member
  • ****
  • Posts: 304
    • Romania, Bucharest,7b
    • View Profile
    • Plante tropicale
Re: Mango graft problem
« Reply #6 on: August 21, 2018, 06:19:30 PM »
Do not use peroxide or bleach on plants, they will kill the tissue then the whole plant. Copper products use with caution, if possible spray the scion few days before you cut it. Otherwise just match the diameter and graft on green bark.

Cookie Monster

  • Broward, FL Zone 10b
  • Administrator
  • Hero Member
  • *****
  • Posts: 4269
  • Eye like mangoes
    • Tamarac, FL, 33321, 10B
    • View Profile
Re: Mango graft problem
« Reply #7 on: August 21, 2018, 09:42:22 PM »
Here are some tricks to up the % of take on mango:

 - Graft to young rootstock (the portion onto which you graft should be no more than a couple of months old). You can even graft onto red-stage rootstock (just make sure that the scion is hardened off). This helps with cambium binding.

 - If you do cleft, you must ensure that the rootstock has a source of energy to draw from. You can do this by leaving leaves below the graft or "stone grafting" (graft before the 2nd flush after seed sprouting). Otherwise, you can use side veneer, which does not require you to decapitate rootstock.

 - Leave 2 or 3 1/3 leaves on the scion and cover with a plastic bag, keeping in about 80% shade. Remove bag after 1 month and move to sun.

 - Graft during the time of year when mangoes are actively growing. For us, that's Jume - Aug roughly.

 - Use fungicides. You can dip your budwood into a fungicide just prior to grafting.
Jeff  :-)

HIfarm

  • Hero Member
  • *****
  • Posts: 1020
    • Paukaa, HI, USA zone 12b
    • View Profile
Re: Mango graft problem
« Reply #8 on: August 22, 2018, 04:03:45 PM »
Thanks for all the helpful tips, guys.  I used "rootstock" here to differentiate from the scionwood, the rootstocks are actually young trees generally in the 5-7'+ range (both seedling & grafted trees).  The only graft that took this year was one where the scion & the rootstock matched fairly closely in size but last time I grafted, the successful graft was one where I decapitated a seedling rootstock & the rootstock was ~10x greater diameter than the scion.  So, in all cases, the rootstock had plenty of energy for the scions.

I always remove competing buds breaking below the graft, at least until it is painfully obvious that the graft has not taken.

Thanks again for the help!
John

sapote

  • Sr. Member
  • ****
  • Posts: 499
    • USA, CA, Burbank, 10a
    • View Profile
Re: Mango graft problem
« Reply #9 on: August 22, 2018, 04:57:51 PM »
"the rootstocks are actually young trees generally in the 5-7'+ range (both seedling & grafted trees).
....the successful graft was one where I decapitated a seedling rootstock & the rootstock was ~10x greater diameter than the scion."

I assume the scions are around pencil size, and so 5 - 7' talk rootstock with much larger dia than scion. How do make good cleft graft with 10x mis-match dia? I know one could just align one side of the scion to the rootstock, but this is not the prefer way. In this case I would think doing coffin/grave is a better method.

sapote

  • Sr. Member
  • ****
  • Posts: 499
    • USA, CA, Burbank, 10a
    • View Profile
Re: Mango graft problem
« Reply #10 on: August 22, 2018, 05:02:44 PM »
One more thought: with the larger dia root stock -- 10X of scion -- the V cut rootstock of the cleft graft are thick and harder wood to conform to the scion contact surfaces with tape. with less than ideal cambium contact this could be the reason of the failure.

Cookie Monster

  • Broward, FL Zone 10b
  • Administrator
  • Hero Member
  • *****
  • Posts: 4269
  • Eye like mangoes
    • Tamarac, FL, 33321, 10B
    • View Profile
Re: Mango graft problem
« Reply #11 on: August 22, 2018, 06:26:54 PM »
You can get successful takes using the techniques you're outlining below, but % of take is going to be low.

Even though the rootstock is 5 - 7 feet tall, nixing all foliage means that it has to dip into its woody reserves, and a tree that young doesn't have a lot (especially if you're snipping down nearer the ground).

If you're working with rootstock that old, here are a couple of suggestions to up your rate of take:

 - Graft 5' in the air (where the greenest wood is). Cambium on green wood is less differentiated (loosely translates to more cambium -- I learned this from Har). Also leave some foliage below the graft to give the tree a way to photosynthesize.

 - If you want to graft lower, use a side veneer. But, again, rate of take is going to be a little lower when you're grafting to the woody part of the rootstock. The advantage of grafting lower is that you can leave the rest of the tree intact -- free to photosynthesize.

Your goal is to get cambium binding as quickly as possible, and when the tree has to dip into its reserves to grow, that cambium growth isn't going to be at an optimal rate. Once the cambium bonds (between 1 and 3 weeks depending on season), you're good to go, as the scion is now receiving energy from the rootstock.

If you're having to remove competing shoots, then the likelihood that a cleft graft will take is pretty low. If the new shoots are below your graft, the tree will self-prune the portion of the tree above the shoots -- meaning that little piece of wood that the graft is on is being abandoned by your rootstock (not good!). This type of situation can work if you're using a side veneer, where the shoots are above the graft (thus cambium growth is happening at the location of the scion).

Thanks for all the helpful tips, guys.  I used "rootstock" here to differentiate from the scionwood, the rootstocks are actually young trees generally in the 5-7'+ range (both seedling & grafted trees).  The only graft that took this year was one where the scion & the rootstock matched fairly closely in size but last time I grafted, the successful graft was one where I decapitated a seedling rootstock & the rootstock was ~10x greater diameter than the scion.  So, in all cases, the rootstock had plenty of energy for the scions.

I always remove competing buds breaking below the graft, at least until it is painfully obvious that the graft has not taken.

Thanks again for the help!
John
« Last Edit: August 22, 2018, 06:28:44 PM by Cookie Monster »
Jeff  :-)

HIfarm

  • Hero Member
  • *****
  • Posts: 1020
    • Paukaa, HI, USA zone 12b
    • View Profile
Re: Mango graft problem
« Reply #12 on: August 23, 2018, 02:53:33 PM »
Ok, I guess I was not providing enough detail.  I have been using "rootstock" as terminology to differentiate the host plant from the scion.  All of the grafts from this recent round of grafting has been on smaller branches (probably 3/8 - 3/4" diameter).  These were all relatively young branches.  The goal was a cocktail mango tree, not decapitating a tree for conversion to a new cultivar.  There was still lots of leaves present for energy (both below the graft and on adjacent, ungrafted branches) as well as lots of stored energy as these are fruiting sized mango trees with significant mass.

There was only a couple of grafts from the previous time attempted with large diameter wood (I know success rate is lower in this scenario but I was just trying to mention that the success rate was not strictly related to scion size matching the "rootstock" in my attempts).  I know of people in the area who have successfully topworked other tropicals, in some cases, where the "rootstock" was 6-8" diameter, maybe more.  But these were not mangoes.

It seemed to me to be a bad sign that the lower buds were developing into competing shoots but it seems to indicate to me that this is showing the tree is in a (very) active growth phase, which is what I assume you would want.  I'm not sure why the scions did not kick into gear & start sprouting.  Next time around, I will probably concentrate on the "grave/coffin" graft method.  This will also allow me to leave leaves above the graft, perhaps that will be more helpful.

Oh well, back to soggy hurricane Lane.  I've got a break in the torrential rain for a moment so internet was back up again (down most of yesterday).

John

Cookie Monster

  • Broward, FL Zone 10b
  • Administrator
  • Hero Member
  • *****
  • Posts: 4269
  • Eye like mangoes
    • Tamarac, FL, 33321, 10B
    • View Profile
Re: Mango graft problem
« Reply #13 on: August 23, 2018, 03:58:18 PM »
OK. I get it now. Try side veneer (at the same spot where you're clefting -- leaving leaves above the graft point). What typically happens is that the tree will prune that section of branch that the scion is clefted onto -- usually just below the V cut. Side veneer works really well in this situation though.

Ok, I guess I was not providing enough detail.  I have been using "rootstock" as terminology to differentiate the host plant from the scion.  All of the grafts from this recent round of grafting has been on smaller branches (probably 3/8 - 3/4" diameter).  These were all relatively young branches.  The goal was a cocktail mango tree, not decapitating a tree for conversion to a new cultivar.  There was still lots of leaves present for energy (both below the graft and on adjacent, ungrafted branches) as well as lots of stored energy as these are fruiting sized mango trees with significant mass.

There was only a couple of grafts from the previous time attempted with large diameter wood (I know success rate is lower in this scenario but I was just trying to mention that the success rate was not strictly related to scion size matching the "rootstock" in my attempts).  I know of people in the area who have successfully topworked other tropicals, in some cases, where the "rootstock" was 6-8" diameter, maybe more.  But these were not mangoes.

It seemed to me to be a bad sign that the lower buds were developing into competing shoots but it seems to indicate to me that this is showing the tree is in a (very) active growth phase, which is what I assume you would want.  I'm not sure why the scions did not kick into gear & start sprouting.  Next time around, I will probably concentrate on the "grave/coffin" graft method.  This will also allow me to leave leaves above the graft, perhaps that will be more helpful.

Oh well, back to soggy hurricane Lane.  I've got a break in the torrential rain for a moment so internet was back up again (down most of yesterday).

John
Jeff  :-)

 

Copyright © Tropical Fruit Forum - International Tropical Fruit Growers