poisoning hedges

Hi
I have a Leylandii hedge which I know my neighbour wants me to get rid off and replace with a wall at my own expense. I want to keep my hedge but this year for the first time it looks as if it is dying. It has gone really brown and it is turning to dust when you touch it. It has lost almost all of its green colour. It is about 19 years old and I keep it trimmed. I don't ant to sound paranoid but I'm sure he is trying to kill it by puting chemicals into the ground at the base. I'm looking for advice about what i ca do as I am also concerned re cats which roam around here. Please advise. Thank you.

Poisoning Leylandii

Hi Morag
I could be way off here as I'm no expert but we had a simillar situation to this starting last year. The conifer needles all seemed to turn brown and just drop off at a touch on those between the neighbour and myself (they are the neighbours trees). Consider Needle Blight as this seems to match the description. Also I'm told it gets worse after a period of wet weather. Like last summer.