Extra! Extra! Leaders concealing crops loss (7)
I believe the answer is:
eclipse
'loss' is the definition.
'extra extra leaders concealing crops' is the wordplay.
'leaders' indicates taking the first letters.
'concealing' means one lot of letters goes inside another.
'crops' becomes 'clips' ('clip' can be a synonym of 'crop').
The first letters of 'extra extra' is 'ee'.
'ee' placed around 'clips' is 'ECLIPSE'.
(Other definitions for eclipse that I've seen before include "famous racehorse" , "concealment" , "screen, more or less" , "Heavenly event; drake's time of dull plumage" , "Heavenly phenomenon" .)