I used this logic so that my Update/Insert trigger would not fire when updates/inserts are being made by SSIS packages:
Declare @Program_Name Char (256)
Set @Program_Name = (Select Top 1 program_name From Master.dbo.sysprocesses Where SPID = @@SPID)
--select * from sysprocesses where program_name like '%ssis%'
--Exit trigger if this is triggered by SSIS
If @Program_Name Like '%SSIS%'
RETURN --This exits the Trigger
Else
Begin
--Execute Trigger Logic Here
End