Mango tree issues

[Mamabear0023]

grown from seed mango, need help!
Hey guys, my sons and I went through the process of growing a mango plant from seed. Up until about 3 months ago it was doing so well, it was growing gorgeous long leaves, and now its looking very drab. The leaves are going brown, there is a whiteish growth where old trimmed leaves used to be...

 

[Logan]

Hi don't know much about mango tree so here's a video