You should mix the fertilizers or insecticides with AFSA-80 which is available it will start giving the result with in week, it will go inside the tree and will reach tree leaves and will make the apple tree leaves open and the fruits quality and quantity will increase.
You just need to give them some time this has not been a good year for the poor apple trees mine blossomed almost a month late due to late frosts and snow.
Be sure that your apple tree is getting an adequate amount of water. Trees with leaves on them that aren't maturing fully, or have leaves that appear partially curled up, are frequently suffering from not enough water.
