Filtering results by date

I have the following query:

SELECT STOCK.ITEM_DATE, STOCK.AMOUNT, STOCK.OPERATIONTYPE   
       ,ITEM.ITEM_NAME 
FROM ITEM INNER JOIN STOCK ON STOCK.ITEM_ID = ITEM.ITEM_ID    
WHERE STOCK.ITEM_DATE > to_date('06/26/2013','mm/dd,yyyy')    
      AND ITEM.CATEGORY_ID = 1

I want to select all items before ’06/26/2013′ INCLUDING ’06/26/2013′, but the result is before ’06/26/2013′ NOT including ’06/26/2013′.

Any ideas how to do that, i tried >= but nothing changed.