I'm going to use florist wire to secure in the Oasis florist foam to the pumpkin container. Designers usually use greening tape for this, but the slick surface of the pumpkin doesn't let the tape adhere well.
Instead I simply use a piece of 24 gauge wire an insert it deeply into one side of the pumpkin. If you wish, pull it up thru and twist the cut end around the standing wire.
Repeat the same for the other side, looping the wire tightly across the top of the florist foam.
I repeat the same in a cross pattern, pulling the wire down into the foam to keep it from sliding around.