Incidence, Resistance, and Evaluation of Chemical Controls for Bacterial Soft Rot in Carrot Stecklings

Series/Report Number: COARC2015

Abstract: Bacterial soft rot, caused by Pectobacterium spp. (formerly Erwinia carotovora), can be an important disease of certain carrot steckling lines used for hybrid carrot seed production. In surveys conducted in two hybrid Kuroda steckling-to-seed carrot seed fields in Jefferson County, OR during the summer of 2014, between 22 and 43% of female plants exhibited soft rot symptoms. A follow-up survey in 2015 observed between 19 and 27% of female plants with soft rot symptoms. It has also been observed that symptoms in the field are more severe on the female line compared the male line. The objectives of this study were to: 1) quantify the incidence of soft rot infection in stecklings used for hybrid seed production; 2) determine if the male line is more resistant to soft rot than the female line; and 3) test the efficacy of chemical treatments to reduce losses caused by soft rot.