Thanks

chop it down and put something there much nicer instead but my personal ideas aside i realy havnt got a clue it sounds quite strange realy almost like someone has sprayed that bit with something nasty .

When you say dead patch in the hedge, do you mean that one or two of the individual Leylandii has/have died, or that there are brown branches on an individual Leylandii which is dead growth?

Brown patches on conifer types is often caused by drought,might that be a possibility if the land drains differently in the middle of the hedge? Is something overhanging the hedge in the middle which might reduce the moisture getting to it? Once Leylandii has dead growth it does not seem to be able to regenerate - my neighbour tried to cut back the other neighbour's Leylandii and removed about one side of the end one and it has not regrown at all, and that was a couple of years ago.

I think the only remedy would be cut off the dead branches or remove the whole individual tree plus roots if it is dead or unsightly ( there are companies that can do this) and replace with another healthy one.

Leylandii is currently under attack from a specific aphid that is causing large brown patches to develop. My parents are gradually removing theirs as it has gradually destroyed the plants. Many others on their estate are heading the same way and have been for some years now. The gold clone 'Castlewellan' seems particularly prone to it.

A sure sign that it is aphid attack is to investigate in the area. If there are inner stems covered with black sooty deposit (sooty mould), thats what has caused it. This problem is now found countrywide and has become established for several years in this country.