By Gary1959
United Kingdom 
What can i do i have x2 acer trees only just bought them and i have put int pots they stand about 3 feet and they have black fly. Thank you
4 Jun, 2018
Answers
welcome to GoY,
you can use a soap spray as suggested or a systemic insecticide available from garden centres. I try to avoid chemical sprays as I try to garden to encourage wildlife.
4 Jun, 2018
As they are small, you could spray with a weak washing up liquid solution this will drown them. PY spray is a good contact killer but perhaps not needed for just a small job.
4 Jun, 2018