Hello!

You can spray the trees with an insecticidal soap (you will probably need to spray more than once) or use the foliar applied systemic insecticides Orthene or Dimethoate. I would consider using the soil applied systemic insecticide imidacloprid next year in the spring to prevent aesthetic damage (it takes about a month to show results so probably not the best option to use for results this year). However make sure you do not apply any insecticide when the trees are in bloom to protect pollinators and always make sure to read and follow the label instructions. Luckily this pest only causes aesthetic damage and will not harm the health of the tree. Dormant season horticultural oils do not work for leafcurling aphids because they do not overwinter as eggs like other aphids.