The county treasurer shall pay the principal of, premium, if any, and interest on the bonds upon maturity, redemption, or purchase in the open market from any moneys in the fund created for the payment thereof. The county treasurer may disburse moneys in the fund to the fiscal agent or trustee appointed by the board for the purpose of paying the principal of, premium, if any, and interest on the bonds for which the fund was created, without any authorization from the board.