Yellowing Needles

[badabing888]

Hi Guys,

One of my JBP seems to be getting yellowing needles it was decandled about 7 weeks ago and begun it's second flush and was looking good but in the last week it's started yellowing and some of the needles at the top have begun to go black from the top.

I was away over the last 5 days and it seems to have gotten worse especially since the extreme temps we've had in perth over the last week.

Thoughts?
Is it fungal?, needle cast?

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Regards

Daniel

[Kevin]

Hello Daniel,

The below thread is extremely informative and may assist you:

viewtopic.php?f=131&t=21150

Good luck with your diagnosis,
Kevin

[badabing888]

Thanks for the reply Kevin hard to tell form that thread it seems to be a argument between old needles falling off, heat related issues or some fungal infection loooool

its interesting to see worse on the top / outside needles rather then the interior.....

Can anyone confirm if it is fungal is there something i can use to treat it anyway as a precaution....

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[shibui]

These outer needles are not the older ones so I would discount old needles as the cause.
Fungal infection is possible. Use any copper based fungicide - kocide, Copper oxychloride, etc. Copper spray will not hurt, even if the problem is not fungal.
Another possibility is root rot of some sort. Is it possible to lift it out of the pot without disturbing the roots too much so you can check for fresh, healthy white roots.
Another possibility is that it may have been too dry at some stage. Pines can tolerate fairly dry conditions but it is possible to keep them too dry and damage the leaves.
Starvation is also possible but if you have been feeding regularly that is not likely.

[John_M]

Guys

This looks like heat stress to me. You have mentioned it was very hot where you are. I have referred to Leong's "bible" on pines (Bonsai South). He refers to the environmental conditions and also has a picture of it in his book. Looks very similar to this. Not much can be done if the needles are burnt. Just maintain your normal routine and monitor progress.

[badabing888]

Hi Thanks for the reply,

I actually have a second tree with similar symptoms but nowhere near as bad so i lifted this one and inspected the roots.

1. No problems noted
2. I bought some copper fungicide Copper oxychloride so i'll use that regardless
3. I've attached some photos of the root ball of the less affected ones this was just after watering and this is younger in a training pot and due for a repot soon.
4. The mix in the older tree is quite open akadama / organics mix but the one i lifted is strait bonsai mix, all other JBP are on a similar watering schedule without the same weird black / yellow needles
5. Actually the only thing i have changed this year is fertilizer type for all my trees i wonder if i have overfed? i used trofrote slow release with charlie carp every few weeks.

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[wrcmad]

Guys

This looks like heat stress to me. You have mentioned it was very hot where you are. I have referred to Leong's "bible" on pines (Bonsai South). He refers to the environmental conditions and also has a picture of it in his book. Looks very similar to this. Not much can be done if the needles are burnt. Just maintain your normal routine and monitor progress.

Agree with heat stress.
Using the below attached flowchart of pine problems, points to alkaline soil / salt damage / heat stress.

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[treeman]

If you want to find out or get closer to finding out what's going on you need to get some detailed close up pics of the roots. Also, pull some of them apart to see if they are rotting. Exactly what kind of fertilizer and how much/often have you used it? Heat alone should not cause this but exactly how hot is hot?. I also doubt fungal attack on the needles. Are the pots receiveing sun directly onto their sides? Are the trees in full sun and are there other plants near these which are unaffected?

[badabing888]

Hi All,

Thanks for the reply.

Basically i have about 12 JBP, 8 were decandled 3 of them seem to be showing a similar issues the others not. Any which were no decandled are not showing the same issues but in general but they are mostly in colanders and are younger etc so are a bit different.

Basically i gave them a good soak in seasol after decandling then fed them 14 days after decandling with slow release as per the general instructions attached is the photo, and resumed the standard charlie carp every 1-2 weeks a week after feeding them slow release.

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Well looking the the outside readings it was 37,40,40,39 4 days strait, all are in full sun with pots also in full sun on the same grow bench, a mix of ceramic bonsai pots and plastic training pots. A point to note is it started slowly yellowing and progressed to the current photos over the space of about a week with it slowly working its way down top to bottom.

Proper close ups of the roots

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Hope this helps!

[treeman]

Ok, so assuming that brand of fert is a genuine slow release (6-9month??) ( A formulation for three months will release twice as much feed as the 6 month) You definitely have root rot. This is very noticeable in the last pic especially. So that is your problem. Black tips on the needles is a good clue. The reason could be simply too much water held in the mix between waterings (The mix is very fine. This is not a problem in itself but it's easily over watered and easy to make mistakes)
It could also have been caused by the roots cooking in the pot. Once the temp in the soil rises to 50 or 60 degrees - something which can easily happen in full sun during a 40 degree day - the roots are dead. Or at least some of them. Once that happens, there is no defence against root rotting pathogens and soon the whole plant is dead.
Your solution if there is one (It might be too late) is to remove as much dead root as possible cutting back to healthy tissue (light coloured), remove as much soil as comes away easily and repot into a smaller pot. Use a potting fix the same mix texture as the one there now. DO NOT use a coarser mix. This is important! using a coarser mix around a finer mix will lead to a quick death of the remaining roots. Use a clean fresh mix and a small pot just big enough to hold the roots. If you have some healthy trees that you can take some mycorrhizae from, mix some into the new mix before you pot. If you can find an unglazed terra cotta pot, that would be good as it would dry quickly, which is what you want. If the new mix is reasonably moist, don't water for a couple of days then water well and let dry almost completely before repeating. Keep the trees in a shady spot - not too shady - and don't fertilize at all. Mist lightly as often as you can. If they are to recover, it will take a year. I know that's a lot of Ifs but if ( ) you do nothing...who knows what will happen!

Best of luck. Let us know how it goes.....

P.S. I know that in WA they sometimes use karri (?) bark in some mixes. Try to find some as it has extremely strong pathogen inhibition properties, and use some in you normal pine bark mix.

[shibui]

Yep. Definitely something wrong with those roots. Should be able to see fat, juicy, white tips on all those roots when they are healthy. I can see a few live ones - light brown colour - but all the bottom ones look black and dead.
Try working through Treeman's list and

[badabing888]

Hi Guys,

Thanks for that i'll make a plan and see how it goes tonight.

Yeah it's 3 month slow release, if that classifies as slow release....

It's interesting to note the most affected one is in a unglazed brown bonsai pot with a much much more "open' mix of medium size 2/4 akadama, 1/4 river stone 1/4organics. I wonder how those roots will look once out of the pot.
Is there any fungicide i should use before repotting into clean mix to kill any remaining pathogens?

[badabing888]

Hi All,

Thanks everyone for the helps thus far i thought i'd post this after i took the eldest bonsai out the photo's may help someone else out so here is what i found.

The roots were curled around the bottom quite heavily

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I untangled and removed these as they looked dark brown and dying / dead

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tangled semi dead roots

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I cut back to what appears to me the most alive roots without removing a huge amount as this would be an issue with a JBP

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They seemed white inside still after cutting them i then

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This was the mix in use the akadama has begun to break down in some places quite alot

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I basically disinfected the pot, used a mix as close to as i could get to the current one, potted up and watered not too deeply as the mix was dry.

So fingers crossed it makes it back

[wal]

What's the odds of this actually surviving? Truly hope it pulls through

Regards
Wal

[wrcmad]

medium size 2/4 akadama, 1/4 river stone 1/4organics.

I'd have trouble with my pines if I used this mix - not free draining enough, and the mix would stay too wet - average annual rainfall is quite high in my part of the world.
Akadama is used as the moisture retaining component of a soil. Alternatively, organics can be used as the moisture retaining component.
Your mix being composed of 75% moisture retaining components is around double that of usual conifer substrates, and as a result may be too wet.
Usual mix is about 1/3 moisture retaining component.
Just a thought.