Answer
It is mustahab (commendable) to remove the hair around the private parts before putting on Ihraam.
Yes, if more than 40 days has passed without removing the hair, then it will be necessary,and failure to do so would render one sinful, however this will not impact on the validity of the umra. (Durrul Mukhtaar ma’a Raddul Muhtaar Vol.2 Pg.481-H.M.Saeed)
and Allah Ta’ala Knows Best
Mufti Ebrahim Desai