Help! What does this yellowing mean?

[Jrs1672]

i just noticed this today. I'm not sure if this is normal? Is it fungus? The needle tips are yellowing over most of the cork bark JBP.

 

[Leo in N E Illinois]

hard to say, looks like fungus - maybe, this is not typical needle cast. It could also be the tree got too dry between watering? Or could be too wet for too long. What changed in your normal routine?

I would treat with Daconil, or Cleary's 3336. Either will slow spread of fungus. The affected leaves won't return to green, but it can spot the spread.

You will have to decide whether watering was the cause. Over or under.

 

[Dav4]

I wouldn't think fungal as it's all at the needle tips and so uniform. Perhaps, it's indicating a soil moisture issue, but it appears pretty minor? I wouldn't worry to much about it, but I would look to see if the soil is staying a tad too wet between waterings.

 

[0soyoung]

If you consulted this resource you would know that this is not indicative of a fungal infection.

I suggest you see if the yellowing becomes more diffuse, as would be indicative of a root problem, or the tips begin turning brown before you do anything. Of late, root aphids are a new found problem (will cause general yellowing). Even though this was thought to be just a CA issue, it has also turned up in Alabama.

 

[JoeR]

I wouldn't think fungal as it's all at the needle tips and so uniform. Perhaps, it's indicating a soil moisture issue, but it appears pretty minor? I wouldn't worry to much about it, but I would look to see if the soil is staying a tad too wet between waterings.

He said it is happening over most of the needles so I wouldnt say its minor.

 

[Dav4]

He said it is happening over most of the needles so I wouldnt say its minor.

Just looking at the pictures provided, I personally wouldn't be overly concerned, but would attempt to ascertain the underlying cause and remedy it.

 

[0soyoung]

This kind of yellowing in the winter is part of the normal dormancy process for many evergreen species; subalpine fir (abies lasiocarpa), lodgepole pine (p. contorta v. latifolia), and Japanese white pine (p. parviflora) are examples. Even ponderosa. It is unusual for a Japanese black pine (p. thunbergii), but maybe it is normal for this variety of corkbark.

The yellow coloration is produced by elevated levels of xanthophylls that protect the photosynthetic apparatus from being damaged. Photosystem 2 (PSII) captures photons and breaks down water molecules into H+ (protons) and oxygen in the thylakoid lumens at a rate that depends only on the incident light. The protons and oxygen, however, are moved out of the lumens by enzymatic processes whose rates decline with decreasing temperature. So, if something weren't changed, the level of reactive oxygen species and of the thylakoid lumen pH would rise to damaging levels when it is cold. The xanthophylls divert the energy of captured photons away from PSII and into heat instead.

Again,

I suggest you see if the yellowing becomes more diffuse, as would be indicative of a root problem, or the tips begin turning brown before you do anything.

 

[Jrs1672]

Thank you everyone for the input. It has rained a lot lately and the tree does need to be repotted as water isn't draining as fast as it should. I hope the issue is only that it has been too wet lately.

 

[jriddell88]

Let's see the whole tree!!!

 

[drew33998]

Not to take over the op thread but my pine is doing the same. I bought it late spring last year. It was in a small plastic bonsai container. Instead of repotting I gently loosened the outer layer of roots/soil and placed it in a larger pot for growing. I am wondering if I should leave it for another year or try to repot it now, bare rooting one half on the root ball to get rid of the old soil. What are your thoughts? It has set many buds. Here is the tree http://www.bonsainut.com/threads/new-to-jbp.19692/#post-281419