By Macone
United Kingdom 
I have an apple tree, var. Grenadier, which suffers from bitter pit and I have read that this is treated with calcium but I have not found any details of when and how this is applied could someone provide any information on this. R Macmillan
4 Apr, 2011
This seems to be a complex problem involving lots of (interesting) science. Basically the fruit and shoots are competing for the Calcium. The best remedy seems to be to make sur you prune the tree to remove excessive shoot growth and get the tree to produce lots of fruit. More fruit, less Ca for the shoots. If you're interested go to http://www.canr.msu.edu/vanburen/bitpit.htm
for the sciency bit!
5 Apr, 2011