Termite starts eating roots of the tree

You should spary boric acid that stop nervous system of insects Then also use arsenic dust and also high sunlight kills the termite

Also use of salt is best and cheap method of control

I would refrain from using arsenic dust as soil and ground water would be polluted. A systemic insecticide on the plant, along with soil application of chlorpyriphos or fipronil will kill the termites

Chloropyrifos 48 EC could be appropriate.

Hanu Khola Use dursban 2 to 4 ml per litre of water and spary it on trunk of mango tree.