Ethylenediurea (EDU): A research tool for assessment and verification of the effects of ground level ozone on plants under natural conditions

Abstract Ethylenediurea (EDU) has been widely used to prevent ozone (O 3 ) injury and crop losses in crop plants and growth reductions in forest trees. Successful use requires establishing a dose/response curve for EDU and the proposed plant in the absence of O 3 and in the presence of O 3 before initiating multiple applications to prevent O 3 injury. EDU can be used to verify foliar O 3 symptoms in the field, and to screen plants for sensitivity to O 3 under ambient conditions. Despite considerable research, the mode of action of EDU remains elusive. Additional research on the mode of action of EDU in suppressing O 3 injury in plants may also be helpful in understanding the mode of action of O 3 in causing injury in plants.