A Preliminary Evaluation of Rumex Rust as a Biological Control Agent for Curly Dock. Robert E. Inman, Plant Pathologist, Stanford Research Institute, Irvine, California 92664; Phytopathology 61:102-107. Accepted for publication 28 August 1970. DOI: 10.1094/Phyto-61-102.
Effects of infection by Rumex rust, Uromyces rumicis (Schum.) Wint., on seed production and rootstock vigor of curly dock, Rumex crispus L., were studied under natural conditions. Comparisons were made between rusted (inoculated or naturally infected) plants and plants protected from infection with a fungicide. Average seed yields from healthy samples were greater in total sample weight and seed number than from rusted samples, but differences were not significant. Distribution of seed weights in samples was shifted toward lighter weights by infection.
In rusted field plots, 43% of the plants resumed growth the following spring, as compared to 95% in fungicide-treated (nonrusted) plots. Dry weight of roots from fungicide-treated, potted plants was 85% greater than that from potted, rusted plants.
The 36 crop selections inoculated with urediospores were immune to infection. Of 12 weedy, experimental polygonaceous hosts, only Rumex maritimus was susceptible. Attempts to infect the alternate host, Ranunculus ficaria L., and ornamental ranunculaceous selections by teliospore inoculations were unsuccessful.
Additional keywords: phytopathogenic weed control.