Mango(Alphonsa) plant

I bought two plants of mango, which arrived from FL(Evergrades Farm). I plan on growing it in pot since I leave in Warner Robins, Ga 31088, south of Macon Ga. I am sure my both plants have anthracnose disease which is in a early stage. What should I apply to my plant to cure it. The Evergrades farm told me to apply soap water. But I want to know from you. Also, I am planning on transferring the plant on a 5 gal pot. So please advice me what should I use every thing from A to Z . I will follow it on a fixed schedule what ever it needs to grow stronger and healthier.