How to dynamically concatenate form results

I've got a workbook with two sheets. Sheet 1 is linked to a Google form with something like the following:

timestamp | fruit | rating

On sheet 2 I want to be able to concatenate the fruit and rating together as results come in, so something like:

Apple_5  
Pear_1  
etc  

Is there a way to automate this? I've been trying to figure out how to combine concatenate with things like import range, filter, etc, but to no avail.