Hi, we moved into a cottage in May 2010 which had an old pear tree, also covered in ivy. We found the main root at the base and sawed through it and pulled off what we could but it was well up all the branches. The ivy has now obviously died off on the branches and is gradually dropping off, we just keep the root under control, could kill it off I suppose. We have a juniper bush growing directly under the tree!
That first summer the tree got scab and rust badly but the fruit was delicious if marked by the black spots - the rust didn't seem to affect the fruit but all the leaves got worse as August went on. I tried to collect all the leaves and burnt them. During the winter we lightly pruned the tree and went to the local garden centre and taking advice from one of the staff bought some fungicide which we sprayed on the tree on 4 separate occasions, starting in the spring when the first leaves started to unfurl and 3 further sprays at intervals of 2 weeks. We were rewarded with a brilliant juicy harvest last year (2011)and no disease. Unfortunately pears don't store but we were giving them away to everyone we knew because they were rotting before we could use or preserve them all, and the family and neighbours couldn't take any more! I was able to collect the leaves for mulching.
Last winter we pruned the tree a bit harder, then this spring because of the wet conditions we were unable to spray on a regular basis but managed the 1st 2 sprayings. We had some black spot and rust but nothing too bad. The fruit yield was well down on last year but still delicious.
My advice would be to go to your local garden centre to ask what is on the market now to spray it with. Ours cost about £10 for 2 small bottles of concentrate two years ago but it goes a long way and we still probably have enough left to use for 4 sprayings next spring and more, weather permitting!
I'll have a look in the shed tomorrow to see what ours is called, but at the moment it's dark, raining and bedtime!