How can i get rid of aphids on my Pear tree ?

I personally don't like using chemicals becoz it does so much damage to good insects as well as bad insects. I don't know how big your pear tree is, but you could try several things. Squash the bugs with your fingers, spray the leaves with water and washing up liquid, or seaweed liquid. If it was me, and it's a largish tree, I would buy some ladybirds/lacewings to eat the aphids. These can be bought online. Hth?

Many thanks for your advice will have ago with the Ladybirds/Lacewings seems the best way to go, will let you know how i go.
Thanks again

You could underplant/nearby this tree with plants that ladybirds and or lacewings like to eat. If you need any ideas, give me a shout and I'll do a blog on it!