This can be handled using authorizations.
Remove change and delete authorizations for infotype 2001 and subtype '0025'.
The authorization object is P_ORIGIN object.
I think we can not disable delete/change button in PA30/61 based upon infotype.
However, we can control it using user exit, as mentioned by Manoj Shakya.
What user exit can do is when the user selects the delete button, we can write code in user exit in such a way, particular operation is not allowed based on infotype, subtype & operations