/**
 * Remove Post Title from Breadcrumb.
 *
 * Takes a substring of crumb, starting at 0, with a length of up to the last occurrence of the
 * (start of the) separator string.
 */
function be_remove_title_from_single_crumb( $crumb, $args ) {
  return substr( $crumb, 0, strrpos( $crumb, $args['sep'] ) );
}
add_filter( 'genesis_single_crumb', 'be_remove_title_from_single_crumb', 10, 2 );