Hi Kuldeep,
You can check it on Form_Data_Load Event of BOM Form.
Also this query can help you to get the time when an item was used in GRPO:
SELECT Top 1 (DATEADD(DAY, 365, PDN1.DocDate)) as 'Date' FROM OPDN INNER JOIN PDN1 ON OPDN.DocEntry = PDN1.DocEntry Where ItemCode = '" + ItemCode + "' Order by OPDN.DocEntry DESC
Hope it helps.
Thanks & Regards
Ankit Chauhan