Greenfly on silver birch

This is the second spring we have had this silver birch. Last year, when it got covered with greenfly I asked for advice where we'd bought it and they sold me some nasty pesticide. It did the trick, but I didn't like using it.
I had tried washing up liquid first and that made no difference.
Is there anything else I can try? Will it matter if I don't treat them?

 

just an idea have you tryed you bath water??
you can keep that in bottles and there should be plenty of soap in it never tryed it myself tho

 

Good idea, but we don't have baths, only showers. Perhaps the soapy water method requires more persistance?

 

Daisybelle, I have put a answer to this problem that is similar to yours on a thread by pr1970 on his Acer

 

I wouldnt bother spraying, spraying trees is rarely practical and most problems are short lived.

 

Hi

I have a similar problem with my silver birch - can you tell me what the presticide you used was called?

Thanks
Catinwaiting