my dog hates jack russells..what can I do?

[washingmachinefiend]

I have a one year old lakeland terrier, he is brilliant at home, really well behaved, great with the kids etc

When we are outside he has a tendency to run after other dogs and not come back but this is improving slowly, with the help of treats and a magic bag of chicken!!

When he goes after other dogs he is only really wanting to play but he can be very boisterous, and not all other owners are very understanding.

However my main problem is he cannot resist chasing and being aggressive with Jack Russells!! he can spot them a mile off, and theres no catching him. he is also much rougher with them than any other breed, so much so that I am frightened he may do them some harm. Lakelands are bred for ratting and it worries my that that's what he thinks they are.

Hehad a couple of run ins with aggressive Jack Russells when he was a much smaller puppy and I am worried that this has now established this unacceptable pattern of behavoiur.

Is there anything I can do to cure him ????

If he had run-ins with JRTs and is now acting aggressively to this breed specifically, he's probably trying to defend himself. He sees them as a threat and he's attacking as a means of defence. Really, your best bet is a professional trainer / behaviourist - look for one who uses positive reinforcement (try the APDT website).
In the meantime, if you suspect JRTs are around, keep him on the lead. The way he's acting, you could be lumbered with a big vet's bill for some poor JRT, plus he could carry on the cycle - giving the dog he attacks the same fear that he has. Is he clicker trained? If so, when you approach a JRT (keeping on lead), make sure to keep his attention. Praise him for ignoring the other dog. Speak to him, get him to do sits in exchange for food. Anything to desensitve him. But do make sure there's no risk of him attacking the other dog if you do this.