Depending on the Brand you are using? I've used Southern Ag Liquid Copper Fungicide and for Mango and here's what it says:

"Mangos Anthracnose 4 tsp. to one Gallon of water Apply at 30 day intervals from the time the pannicles are 2 inches high until all fruits are set until August"

It sounds like you can spray the blooms with it as long as you do only once a month...When in doubt Contact the Company of the (Brand) of the product you are using....they are usually very helpful and should be able to tell you "if" its safe to spray the Booms/Flowers...a lot of times its best not to spray the blooms or else the bees won't pollinate them...Good luck!

Here is a link that might be useful: Southern Ag LIquid Copper Fungicide Label

alright thanks. another problem now is how safe that stuff is to use indoors. i got this thing potted

DO NOT DO IT INSIDE. YOU WILL BE SORRY!

Not because it's toxic to you, but because it will end up staining your walls, carpet, tile grout, and everything else blue.

woo. i read up on that. so i got neem oil instead, its a natural fungicide/pesticide.. so i sprayed the buds and leaves with the 90% neem oil and then ended up putting it outside lol