A method of monitoring and controlling a condition of a wind turbine rotor blade , the method comprising the steps of: - performing a first measurement comprising the sub-steps (S3, S4) of: - measuring a first value of voltage applied to a conductive device of the wind turbine rotor blade ; and - measuring a first value of current flowing through the conductive device, the first value of current corresponding to the first value of voltage; - calculating a first resistance value of the conductive device depending on the measured first value of voltage and the measured first value of current; - performing a second measurement comprising the sub-steps (S7, S8) of: - measuring a second value of voltage applied to the conductive device, the second value of voltage being higher or lower than the first value of voltage; - measuring a second value of current flowing through the conductive device, the second value of current corresponding to the second value of voltage and the second value of current being different than the first value of current; - calculating a second resistance value of the conductive device depending on the measured second value of voltage and the measured second value of current; and - comparing the first resistance value and the second resistance value in order to determine the condition of the wind turbine rotor blade . - performing a first measurement comprising the sub-steps (S3, S4) of: - measuring a first value of voltage applied to a conductive device of the wind turbine rotor blade ; and - measuring a first value of current flowing through the conductive device, the first value of current corresponding to the first value of voltage; - measuring a first value of voltage applied to a conductive device of the wind turbine rotor blade ; and - measuring a first value of current flowing through the conductive device, the first value of current corresponding to the first value of voltage; - calculating a first resistance value of the conductive device depending on the measured first value of voltage and the measured first value of current; - performing a second measurement comprising the sub-steps (S7, S8) of: - measuring a second value of voltage applied to the conductive device, the second value of voltage being higher or lower than the first value of voltage; - measuring a second value of current flowing through the conductive device, the second value of current corresponding to the second value of voltage and the second value of current being different than the first value of current; - measuring a second value of voltage applied to the conductive device, the second value of voltage being higher or lower than the first value of voltage; - measuring a second value of current flowing through the conductive device, the second value of current corresponding to the second value of voltage and the second value of current being different than the first value of current; - calculating a second resistance value of the conductive device depending on the measured second value of voltage and the measured second value of current; and - comparing the first resistance value and the second resistance value in order to determine the condition of the wind turbine rotor blade . <EOS>