Function to clear data
 

Please help me figure this out:
If I have the months in column A such as:
04/05
05/05
06/05 and so on
and other data in column B
I would like to create a formula where if I enter in a cell 05/05 then it
would clear all the content in column B for the month of 05/05 and all the
months before this.
Thank you so much.
Renee