Thanks Mark n Texas for recommendation. While looking for online source for Keyplex 350 i found this thread a news letter and a source close to Orlando. If i find anything closer i will update thread.
Dr. Ledesma presentation Collier Fruit
Growers Being a World-renowned authority on
tropical fruits, mangoes in particular
Curator of Tropical Fruit
Fairchild Tropical Botanical Garden
Coconut Grove FL
Noris: Use a micro-nutrient foliar spray containing zinc and manganese, i.e., KeyPlex
350TM, three or more times a year. [1. KeyPlex 350 ORTM is an organic product which is
also available. 2. Follow the manufactures application instructions. 3. Consider adding a
spreader/ sticker, i.e., Agricultural soap to increase the contact time.]
http://grossorchids.com/orchid-potting-supplies/http://www.collierfruit.org/October_2018.pdf