When a borrowing member shall be three months in arrears in the payment of his dues and interest or either, or in the payment of his specified monthly installments in the case of a direct reduction loan, the whole loan shall become due at the option of the board of directors; and it may proceed to enforce collection upon the securities held by the association. At the time such option is exercised, the withdrawal value of all shares pledged as collateral security for the loan shall be applied upon the loan and arrearages of interest and fines thereon, and the shares deemed surrendered to the association.