questions: asking about root rot in coconut 
 answers: soil drench with blitox 50 @2gm/l water, two spray at 5 days interval.

soil drenching can be done with bordeaux mixture also: take 100gm lime a
in 5 litre water and 100gm copper sulphate in 5 litre water. then mix the solution in another container. take the final solution and spray 4-5 times a days for controlling the disease.