how to split, remove part of data in column with spreadsheet gem

Using spreadsheet gem and rails

MY CODE GOES BELOW:

book = Spreadsheet.open 'excel-file.xls' sheet = book.worksheet 0 book.write 'output-file.xls'

and here goes the first problem: I want to remove data that comes after ";" (semicolon) in a column. Example below.

FULTON BANK NA;FULTON BANK

I just want it to be FULTON BANK NA for example.