What is it and how to treat this?

[namnhi]

I suspect this is a fungus but not really sure. My concern is that it happen very quickly and the trees that got rarely survived. I have many pines but only some got it and I pretty much use the same soil and same watering schedule.
I open to suggestions as what this could be for further research.
Thanks in advance.

 

[namnhi]

 

[Wires_Guy_wires]

Looks like anaerobic soil conditions to me.

 

[Paradox]

Looks like anaerobic soil conditions to me.

How though?
The soil looks like an open and inorganic mix. If that is the case through the pot, I can't see how it could get anaerobic.

Is there any possibility this could be heat related given the heat we had this summer? Some of the seedlings might be getting effected

 

[AJL]

Also are you sure it's not due to over-fertilising? there seem to be a lot of granules on the soil surface

 

[Wires_Guy_wires]

How though?
The soil looks like an open and inorganic mix. If that is the case through the pot, I can't see how it could get anaerobic.

Is there any possibility this could be heat related given the heat we had this summer? Some of the seedlings might be getting effected

Clogged up pot hole maybe. It's resting on a piece of wood.
Open and inorganic mean very little if air can't come in from the bottom.
A little dash of organics clogging up the holes can be enough to get water to pool.

 

[Dav4]

I've got a few up here in zone 6 MI that have gone yellow this year... all in pond baskets in aggregate soil. I'm assuming root issues- root mealybug vs soil staying too wet- and will be investigating further this coming re-pot season. I had one a few years ago in a APL mix in a terracotta pot that went yellow... the soil was absolutely staying too wet and once I re-potted in fresh soil in a stoneware pot, the new needles were much healthier.

 

[Leo in N E Illinois]

Pursue the possibility of root mealies