APS Abstracts of Presentations

The effects of temperature on urediniospore production in Phakopsora pachyrhizi and development of national risk maps
E. MUMMA (1), R. W. Schneider (1), C. L. Robertson (1), C. G. Giles (1)
(1) Dept. Plant Pathology, Louisiana State University Agricultural Center, Baton Rouge, LA, USA
Phytopathology 97:S81

The primary objective of this research was to determine the temperature range that is most conducive to the production and release of urediniospores of Phakopsora pachyrhizi, causal agent of Asian soybean rust. Quantitative spore trapping data from diseased fields in Quincy, FL were collected for two years, and the results were related to different diurnal temperature parameters. In addition, isothermal growth chamber studies were conducted with field-collected leaves to determine the optimal temperature for urediniospore production and to assess the sensitivity of this process to less than optimal temperatures, including exposure to temperatures above 32°C. Results from these studies and archived daily temperatures for each county in the U.S. were used to construct color-coded maps that show areas of high and low risk for infection and spread of the disease for each month of the season.

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