Hope that you have a sprayer that will reach your trees. I have a commercial sprayer for our fruit trees. I would try a 2 teasp of liquidkitchen soap w 1 qt of water.......you can times that by how much you need to do this tree. You might need to repeat this in 7 days or so.
Now that cooler & colder weather is here you can use dormant spray on them follow the directions on the container for which season you are applying it. Fall, winter & spring spray until the buds open. Once they open I only spray that tree up to the first branch. If you spray after the buds open it will kill the bees. Keep children & pets away until it dries. Wear long old clothes, mask, hat, goggles & gloves. Only make up what you need.