The wasps are probably incidental, they can smell the resinous content of the sap, so are hunting that out. Is the brown low on the tree? Bluespruce, what do you think? Phil J

There is a great deal of this about. I think it is some sort of bug. Maybe red spider mite but I'm not sure. Unfortunately once they are brown that is it they will not grow back

Thanks for response. Agree about the wasps. The brown patches are fairly widespread, over - I'd say - 20/25% of the tree. Bluespruce? If I say I think the tree is a columnar Lawsonii, does it answer your question? And I wonder also if the weather here over last year and this, has upset the tree's mechanism so to speak.

I think Phil was hoping the poster Bluespruce would have a view( I may be wrong though.:))

Leylandi hedges have been badly affected by brown patches this year. I look after a beauty for a customer but an area about 3 feet in diameter has just died. I do not know why as there is nothing obvious to see on the dead foliage.

Conifers do sometimes sufffer from this proble, Chamacyparis covers a huge range of trees all of which are cultivated "sports" off the wild chamaecyparis. A quick look in my plant book shows at least 20 cultivars.

Try google images for chamaecyparis and see if you can spot the one you have

PS if it is very columnular it probaby is C. columnaris! Theres's a photo of one on page 3 on google iif you type in chamecyparis and you'll see all the others

If wasps are involved, the first two things to check out is the possibility of an actual wasp nest in the tree. The other possibility is a major aphid infestation within, which will definitely attract wasps....I suggest you be extremely careful though.

I do believe their are some dark coloured mites in with the decay.(not red spider) Do you think that I will be able to save it? would hate to loose it, last year it thrived in the damp. many thanks for your help.