Would appreciate any advice on how to stop my 2 yr old newfoundland lunging at other dogs.  He has just started doing this a month ago since he was lunged at and it scared the wits out of him, so now he does it first.  I got him when he was 6 mths old and I am not sure if he had been badly treated or just not socialised at all but he was very fear aggressive.  He crawled on his belly and peed himself if we called him in the house and was terrified of other dogs, big or small.   I have had his sister (littermate) since she was a puppy and she is a well adjusted confident little madam.  I also have a springer who is a well balanced, obedient dog.  They helped enormously as when he saw them meeting and greeting other dogs and surviving, slowly realised there was fun to be had in the big wide world! The only trouble has been that due to his early lack of socialisation he acts like a puppy when meeting dogs and is too excitable.  I have therefore got into the habit of just holding his collar when is is off lead and we see another dog so that he doesnt charge up to it and then when we are level with it let him go (just to stop him running at full speed and scaring the dog and its owner).  He is never in the slightest aggressive now even if the other dogs are.  My problem is when he is on a lead walking the streets and a dog passes by.  He lunges and I have to say he looks terribly scarey.  I think it is catch 22 as I suppose if he met more on a lead he would regain his confidence  but I walk the other way if we see another dog as people are terrified.  Any suggestions anyone? 
BTW, He doesnt always do it either, it seems to be only certain dogs.

Had you thought about a Halti to give a little more control over him while you're training?  Then work on getting him used to not reacting to other 'strange' dogs by rewarding him for non reaction even if the dog is a long way away, and slowly reduce the range at which you reward.

Hi Ann ,i know just what you are going through ,i have a 19 month ,10 stone lunging newf but i worry as she has nipped another dog, she has been socialised,and lives with an easy going lovable GSD who she bullies (and he lets her :(  )  The halti really helped until in a mad fit she got her bottom jaw under it and chewed through it ,so i personally found the gentle leader better. I go out armed with a lemon/water spray bottle and ox liver, squirt when bad, treat when good and it is working around the town and at dog training. She is top of the class at obedience and behaves perfectly at training but she still wants to 'kill' everyother dog when we first arrive   we are currently under David Appleby with her and he's sure she is not an aggresive dog,she just has frustrated play..!!! sorry just had to have a moan with someone who may understand :) mand x