Posted: 01/06/2017 at 11:37
It's thought they arrive as young nymphs on bird feathers or creep along the ground. A systemic insecticide might work but would be absorbed into the tree and then poison beneficial insects such as any visiting pollinators, so I don't advise their use anymore. However, as long as you physically get rid of them all it's unlikely to come back. I had a similar infestation on my peach tree about 5 years ago and it hasn't returned after cleaning them all off.