Presence, Viability, and Movement of Puccinia recondita and P. graminis Inoculum in the Great Plains. M. G. Eversmeyer, Research Plant Pathologist, USDA, ARS, Department of Plant Pathology, Kansas State University, Manhattan 66506. C. L. Kramer, Professor, Division of Biology, and L. E. Browder, Research Plant Pathologist, USDA, ARS, Department of Plant Pathology, Kansas State University, Manhattan 66506. Plant Dis. 68:392-395. Accepted for publication 21 November 1983. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1984. DOI: 10.1094/PD-68-392.

Kramer-Collins 7-day spore samplers were used to study availability, viability, and movement of Puccinia recondita and P. graminis urediniospores throughout the year in the Great Plains. From October 1974 to August 1977, the longest period of consecutive days that no spores were trapped at any of the Great Plains locations (Renner, TX; Altus, Goodwell, and Stillwater, OK; and Parsons, St. John, Garden City, Hays, and Manhattan, KS) was 19 for P. recondita and 18 for P. graminis. Estimated viability of urediniospores trapped was 61% for P. recondita and 58% for P. graminis. Viable inoculum was present in the central Great Plains wheat-growing areas most of the time samples were taken; therefore, epidemic development was largely dependent on favorable weather and host-parasite combinations. Forecasted wind trajectories were used to indicate spore movement patterns; however, we were unable to develop significant statistical models of urediniospore movement.