Question: query related to coconut
Answer: please apply bordeaux mixture (direct mixed form) @1 gram per litre water
or, prepare bordeaux mixture at home: mix 100 gram copper sulphate in 5 litre water in a container. in another container mix 100 gram lime in 5 litre water. then mix these two mixtures together and check the ph with a clean sharp knife.  if there is a reddish layer then again apply lime to the mixture till there is no reddish layer left in the knife.