Thuja are dying little by little

It's not about whether Thuja, but how we save it.

Were you able to identify fungus, lice, waterlogging, or something else as the cause? Do you already have a strategy?

If the thujas are completely brown, you have to replace them.

To combat lice, dissolve 50 grams of soft soap in 1 liter of water and spray it. Ants come along with the lice.

Were you able to determine if fungus, lice, waterlogging, or something else is the cause? Do you already have a strategy?

So it probably isn’t fungus. I think there are already lice on some of the thuja... But if I see that correctly, they are probably just normal aphids... and those don’t actually kill the thuja, do they...? We don’t have a strategy yet... How exactly can I recognize waterlogging?

if the roots look rotten and the soil is still wet before watering. Not on the surface, but in the root area. Often the root and the area also smell foul.

Aphids do not destroy the plants themselves, they weaken them. With those things, ants come along. I have an extremely high number of aphids this year.

Do you have acidic or sandy soil? Did you properly tamp down the thujas when planting? Are they or were they watered too little? Overfertilized or wrong? Fresh compost or horse manure or not weighed, but just worked in by feel?