|Bonde, Morris - Mo|
Submitted to: Plant Disease
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/11/2003
Publication Date: 1/1/2004
Citation: BABADOOST, M., MATHRE, D.E., JOHNSTON, R.H., BONDE, M.R. SURVIVAL OF TELIOSPORES OF TILLETIA INDICA IN SOIL. PLANT DISEASE. 88:56-62. 2004. Interpretive Summary: Karnal bunt of wheat, caused by a newly introduced fungal pathogen to the U.S., occurs only in warm areas of the world. Until now, it was not known whether the fungus could survive in the cold northern areas of the U.S. A study was undertaken in which Karnal bunt spore-infested soil was placed in specially designed containers that were buried in a field in Montana. Over the next 32 months, the soil was recovered and percent fungal propagules that were alive determined. Results showed that the pathogen could survive under very cold harsh winters, in which the soil repeatedly froze. Survival was affected by soil texture, burial depth, and time. The information will be important in developing control strategies for the disease, and in predicting where the disease might occur.
Technical Abstract: A study was conducted to determine if teliospores of the Karnal bunt of wheat pathogen, Tilletia indica, could survive in field soil in cold climates. Four soils were infested with teliospores at 10**3 teliospores per gram soil. Aliquots (22 g) of infested soil were placed in 20-um mesh bags, which were sealed and placed at 2, 10, and 25 cm intervals in PVC tubes containing the same soil as in the bags, and the tubes were buried in a field in Bozeman, MT. Over the next 32 months, bags were recovered and tested to determine teliospore recovery rates and percentage of teliospores that would germinate. In 32 months, teliospore recovery on average dropped from 90.2% to 13.3%. Efficiency of teliospore recovery from soil was greatest from a loam soil and lowest from a silt loam soil. Teliospore recovery was not affected by depth of burial. The germination percentage of teliospores on average dropped from 51.3% to 16.5% in 32 months. Teliospore germinability was significantly affected by soil texture and depth. The results demonstrate that the pathogen causing Karnal bunt of wheat can survive the cold climate of the northern states.