Can you not just long-press the widget and remove it? Works with most homescreens.
Otherwise, check the launcher settings. Or in the limit, go into the applications settings, select "All", find the google search app and disable it (I've no use for it myself - I just use a browser when I want to search for stuff). I think this will also disable Google Now, so if you use that then this isn't what you want as a solution.