ARS | Publication request: Analysis of induction and establishment of dwarf bunt of wheat under marginal climatic conditions.

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2010
Publication Date: June 1, 2010
Repository URL: http://riley.nal.usda.gov/nal_web/digi/submission.html
Citation: Goates, B.J., Peterson, G.L., Bowden R.L., and Maddux, L.D. 2010. Analysis of induction and establishment of dwarf bunt of wheat under marginal climatic conditions. Phytopathology 100 No. 6 (Supplement): S41.

Technical Abstract: Dwarf bunt caused by Tilletia contraversa has limited distribution due to essential climatic requirements; primarily persistent snow cover. The pathogen is a quarantine organism in several countries outside of the USA, some of which may have marginal climate for the disease, including the People’s Republic of China. To evaluate the risk of disease introduction, experiments were conducted in Kansas which is a climatic analog to the northern winter wheat areas of China. Four replicate 27 m2 plots, planted with a susceptible cultivar, were inoculated at six rates ranging from 0.88 to 88,840 teliospores/cm2. Three separate nursery sites were inoculated once, each site in a separate season, followed by replanting and examination for disease for 4 to 6 years afterward. Any diseased spikes produced were crushed and returned to the plots. Bunt was induced at trace levels at the three highest inoculation rates in two of the three nurseries. One nursery had no disease during all of six seasons. Disease carryover occurred during one year in one nursery at the highest inoculation rate, but no disease occurred in three subsequent seasons. In all nurseries, the disease eventually disappeared. A duplicate nursery planted in a disease-conducive area showed the highest inoculum rate caused almost 100% infection. This research substantiates the critical importance of climatic conditions for establishment of this pathogen and contributes to pest risk assessment efforts.