Help with Podocarpus!!! Please.

[Mandrew968]

Hey guys! These Podocarpus in the native and Japanese section are not doing so great... We have already lost two or three major sized trees. These brown necrotic patches keep popping up in the canopy. This one I am showing has it bad. I believe it will die unless we do something about it--anyone know what it is or could be? Thanks in advance!

[Mandrew968]

This is an old tree--would hate to lose it!

[Mandrew968]

Last one unless you guys need more--thanks again, in advance for your help!

[Jerry@TreeZoo]

Have you checked for sucking insects?  The trees are old but look uncommonly thin.  Were they shaded out?

[Mandrew968]

No shade. I will get some better shots for you. We lost a couple trees already...

[Mandrew968]

These two are seemingly ok...

[Mandrew968]

This is the trunk of the tree that is most in need of help. I didn't see any evidence of bug intrusion...

[Mandrew968]

And as you can see she is in the sun.

[The Silent Seed]

Unusually dry? 

Unusually wet? 

Those are the two things that have killed Podocarpus in my experience - nothing else. 

[fastfeat]

Can you get some foliage closeups (preferably removed from the tree) and tree pics taken with the sun behind you? Having a hard time seeing much.

Are these all P. macrophyllus ? Dimensions (rough) and ages?

Edited July 13, 2016 by fastfeat

[fastfeat]

Without better pics, my first guess would be some sort of response to a soil toxin, be it an herbicide, salt water intrusion, reclaimed water change, etc. Could be response to restricted irrigation as well.

Trunks appear normal.

[Jerry@TreeZoo]

We have gone about a month without any real rain.  It could be that simple.  Plus, Miami Beach does have a salt water intrusion problem.

[rprimbs]

7 hours ago, santoury said:

Unusually dry? 

Unusually wet? 

Those are the two things that have killed Podocarpus in my experience - nothing else. 

That's what I was thinking.  Unusually dry?

[Mandrew968]

12 hours ago, Jerry@TreeZoo said:

We have gone about a month without any real rain.  It could be that simple.  Plus, Miami Beach does have a salt water intrusion problem.

I didn't want to lead the conversation but this was my first thought. These trees are very established so I don't think it is due to lack of water--A tree this size could go a month without water and it rained heavily about 12 days ago. One two something tree service said it was a fungus in the soil that killed the other two mature trees they cut down (before I was hired) for us. Soil fungus--does that even sound right? And if it is, I am not gonna treat that in our native area--too much potential for habitat disruption. And if it's salt water intrusion, then I can't do anything about that either...

[Mandrew968]

16 hours ago, fastfeat said:

Without better pics, my first guess would be some sort of response to a soil toxin, be it an herbicide, salt water intrusion, reclaimed water change, etc. Could be response to restricted irrigation as well.

Trunks appear normal.

I can get any photo you want; do you want healthy leaves of the died back ones? We don't spray anything in this area so it's not any kind of 'cide'... Appreciate the help guys!

[Mandrew968]

16 hours ago, fastfeat said:

Can you get some foliage closeups (preferably removed from the tree) and tree pics taken with the sun behind you? Having a hard time seeing much.

Are these all P. macrophyllus ? Dimensions (rough) and ages?

I believe so, and the age has to be at least 2 decades?.. the size of the trees are about 30 feet high by 25 to 30 feet wide. I will clip some limbs to photograph.

[The Silent Seed]

Re: the saltwater issue - why would this happen now and not before? Global warming and rising sea levels? 

[Jerry@TreeZoo]

To look for sucking insects you want to see the green leafy tissue not the dead tissue.

 

Check your irrigation for clogged heads.  You might want to dig a hole in the Podo's root zone to see how wet it is.  You can use a post hole digger for a hole only 8" wide.  If you have an extremely high water table you could reach it in only a few feet and take samples for salinity testing.

 

Not to get into Global Warming politics, Miami Beach is a sandy barrier island that has been augmented by burying trees and palms as a land fill decades ago.  This stuff is all decomposing and sinking.  Miami Beach gets salt water flooding a couple times each year so salt is a very real possibility.

[Mandrew968]

Ok, cut a small branch. It doesn't look like any bugs, besides a little spider webbing

[Mandrew968]

Here are two more. Do I need to inspect the green leaves for anything in particular? 

 

As for, "why is this happening now?" over a year ago, the two others were removed due to this seemingly identical issue...

[Jerry@TreeZoo]

I could not get a clear image when magnifying your pics.  I saw something but am unsure if it was water spots or scale or whatever else might be going on.  The leaves do look a bit off in color, a duller color like when they are dry.  We had a very dry summer last year when you lost the others so that might be it.  

 

Dig a hole, stick your fingers in and see if it is moist or gun powder dry.

[DoomsDave]

Here's a link to help from afar:

 

http://lake.ifas.ufl.edu/agriculture/nursery-production/documents/Podocarpus.pdf

[Mandrew968]

1 hour ago, Jerry@TreeZoo said:

I could not get a clear image when magnifying your pics.  I saw something but am unsure if it was water spots or scale or whatever else might be going on.  The leaves do look a bit off in color, a duller color like when they are dry.  We had a very dry summer last year when you lost the others so that might be it.  

 

Dig a hole, stick your fingers in and see if it is moist or gun powder dry.

Jerry, everything around it is not showing any signs of stress--you think this could be the only thirsty plant? I will go check and maybe get a better shot of the leaves... Thanks again!

[Mandrew968]

Here are some close ups. I have since watered the tree and also we got a lot of rain this morning. 

[Mandrew968]

Two more and I guess I will just be monitoring this tree, closely now... Anyone ever hear about fungus in the soil affecting Podocarpus???

[Jerry@TreeZoo]

You definitely have some sort of sucking insect or mite, I cannot tell which.  Some leaves appear clean, some with the insect/mite so I don't know how bad the infestation is, it may be minor or great.  The loss of water and sugars to the pest as well as the dry weather (which encourages more pests) are contributing to the dieback.  

[rprimbs]

I wonder if that is really an insect problem.  I'm no expert on this but is it possibly verticillium, or even fusarium wilt?  That would go along with the hot dry weather and the limited affected area. 

[Jerry@TreeZoo]

The insects are only contributing to the problem IMO.

[fastfeat]

Sorry I haven't gotten back to you sooner. Thanks for that smaller branch pic.

I suspect that you may indeed have some soil=borne pathogen like     Verticillium or Fusarium, since damage is restricted to the older shoots only. This isn't a tree that's particularly subject to fungal issues, so I'm not really certain on a recommendation. But given that you've lost others, the future looks suspect for these. While insects/mites may well be contributing, I think they're of minor importance now. AFAIK, there's no way to test soil for Fusarium, and you're unlikely to find a lab to check the tissue on Podocarpus. You might check with local Ag Commissioner for certain.

No recent changes to soil locally? No compaction/trucks? Herbicide/preemergent applications? Aeration?

[Mandrew968]

On 7/17/2016, 7:33:25, fastfeat said:

Sorry I haven't gotten back to you sooner. Thanks for that smaller branch pic.

I suspect that you may indeed have some soil=borne pathogen like     Verticillium or Fusarium, since damage is restricted to the older shoots only. This isn't a tree that's particularly subject to fungal issues, so I'm not really certain on a recommendation. But given that you've lost others, the future looks suspect for these. While insects/mites may well be contributing, I think they're of minor importance now. AFAIK, there's no way to test soil for Fusarium, and you're unlikely to find a lab to check the tissue on Podocarpus. You might check with local Ag Commissioner for certain.

No recent changes to soil locally? No compaction/trucks? Herbicide/preemergent applications? Aeration?

No soil change in our garden, but about 500 yards away they are doing construction and will be till 2017.