To provide a method which exerts excellent controlling effects on noxious organisms in a field of soybean, corn or cotton.A method for controlling noxious organisms in a field of soybean, corn or cotton, wherein at least one PPO inhibitor compound selected from the group consisting of flumioxazin, sulfentrazone, saflufenacil, oxyfluorfen, fomesafen-sodium, anda compound represented by formula (I):is applied to the field before, at or after sowing a soybean, corn or cotton seed treated with ethaboxam.