Recommendations for mangos are usually within the range of 2 1/4 teaspoons Sulfur per gallon, to, 2 Tablespoons Sulfur per gallon. Higher rates usually show no additional benefit. The University of Florida rate, since 1978, is 1 1/2 Tablespoons per gallon.
One Tablespoon of Sulfur, plus one Tablespoon of Cueva (Copper Soap), per gallon of spray mix, is an easy formula to remember. Besides the mild fungicidal effect that the Copper Soap provides (with minimal Copper content), the soap also makes a very nice spreader-sticker.