Sorghum ergot can develop without local Claviceps africana inoculum from nearby infected plants

Chakraborty, S. and Ryley, M. J. (2008) Sorghum ergot can develop without local Claviceps africana inoculum from nearby infected plants. Plant Pathology, 57 (3). pp. 484-492. ISSN 0032-0862


Batches of glasshouse-grown flowering sorghum plants were placed in circular plots for 24hr at two field sites in southeast Queensland, Australia on 38 occasions in 2003 and 2004, to trap aerial inoculum of Claviceps africana. Plants were located 20-200m from the centre of the plots. Batches of sorghum plants with secondary conidia of C. africana on inoculated spikelets were placed at the centre of each plot on some dates as a local point source of inoculum. Plants exposed to field inoculum were returned to a glasshouse, incubated at near-100% relative humidity for 48hr and then at ambient relative humidity for another week before counting infected spikelets to estimate pathogen dispersal. Three times as many spikelets became infected when inoculum was present within 200m of trap plants, but infected spikelets did not decline with increasing distance from local source within the 200m. Spikelets also became infected on all 10 dates when plants were exposed without a local source of infected plants, indicating that infection can occur from conidia surviving in the atmosphere. In 2005, when trap plants were placed at 14 locations along a 280km route, infected spikelets diminished with increasing distance from sorghum paddocks and infection was sporadic for distances over 1km. Multiple regression analysis showed significant influence of moisture related weather variables on inoculum dispersal. Results suggest that sanitation measures can help reduce ergot severity at the local level, but sustainable management will require better understanding of long-distance dispersal of C. africana inoculum.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2008 CSIRO. Published version deposited in accordance with the copyright policy of the publisher.
Faculty/School / Institute/Centre: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 13 Jun 2014 05:30
Last Modified: 18 Aug 2014 06:21
Uncontrolled Keywords: aerial spore dispersal; long-distance spore dispersal; secondary conidia; sorghum bicolor
Fields of Research : 06 Biological Sciences > 0605 Microbiology > 060505 Mycology
07 Agricultural and Veterinary Sciences > 0703 Crop and Pasture Production > 070308 Crop and Pasture Protection (Pests, Diseases and Weeds)
06 Biological Sciences > 0607 Plant Biology > 060703 Plant Developmental and Reproductive Biology
Socio-Economic Objective: B Economic Development > 82 Plant Production and Plant Primary Products > 8204 Summer Grains and Oilseeds > 820404 Sorghum
Identification Number or DOI: 10.1111/j.1365-3059.2008.01832.x

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