I'm quite new to gardening so this is probably quite a basic question I'm asking.
We have a small apple tree that we only planted in the ground a couple of months ago - so it is growing a lot. It has loads of green aphids on almost every leaf though. I read somewhere that spraying very diluted washing up liquid on the leaves was a fruit-friendly way to get rid of them, however I sprayed them last night and the aphids are still at large.
How long would it take for them to suffocate? Should it be an immediate thing?
What else could we try - please bear in mind it needs to not affect the fruit growing and I don't want harmful sprays on there as I'm pregnant.