This is a question we hear many times during the spring, “When Do I Spray My Fruit Trees?”
The time to spray Fruit Trees is when 75% of the flower petals have fallen off the flower. Use Malathion or Carbaryl (Sevin liquid) in combination with Captan or Chlorothalonil (Fertilome Broad Spectrum Fungicide) or Sulfur.
For a more detailed spray guide check with your local county agent or check out Texas Cooperative Extension of Texas A&M University System website. All the information is there on spraying Fruit and Pecan Trees.