Summary of the 2011 Tobacco Blue Mold Epidemic in North America
Thomas Keever, Lead Forecaster
North American Blue Mold Forecasting System
NCSU, Department of Plant Pathology
The Tobacco Blue Mold Forecasting System has concluded its 16th year of forecasting epidemics for North America. The forecasting website provided visitors with forecasts of potential epidemic spread and up-to-date information about the status of the epidemic. We hope this information has proved useful to the growing community.
The 2011 epidemic was the lightest on record since online forecasting began in 1996. Only 3 U.S. counties reported disease: Chester and Lancaster in PA, and Hampden in MA. There were no reports from any other growing regions in North America.
The first report in 2011 arrived from Chester County in southeast PA on June 22, followed on June 28 by reports from adjacent Lancaster County, PA. These reports involved infections in multiple plant beds in each county. Growers took decisive action after TBM was discovered in each case, which limited the impact of these outbreaks. Despite exhaustive analysis, an explanation for these initial outbreaks via airborne introduction of spores was not forthcoming. There were no other reports of TBM in the U.S. growing regions to the south or west of southeast PA either before or after this period.
Hampden County, MA was the site of the only other report of TBM in 2011. TBM was confirmed here in a field setting, but only a small number of lesions were found on a few leaves. Airborne disease introduction was possible. The transport events of July 2-3 and July 7 are the most likely, based on the associated weather conditions and an appropriate time frame for the appearance of first symptoms (estimated at July 12). Other origins of this outbreak, as well as the PA cases, cannot be excluded.
The weather in the northeastern United States during the summer months can best be described as variable. Periods of dry weather alternated with days where scattered showers were possible / likely, typically associated with passing cold fronts. The dry periods constituted the majority for June and July. Wetter weather occurred more often during late summer. Though there were many opportunities for localized or short-range epidemic spread near the source regions, no other reports of TBM were received in 2011. The growing communities are congratulated, as it appears that decisive action and good growing practices played a large role in control of the infections in southeast PA and southern New England.
We wish to thank all of our cooperators in the U.S. and abroad for their participation in 2011. If anyone would like more information about TBM forecasting or other aspects of the program, please contact Dr. Mila or the Forecast Center.
Dr. Mina Mila
Asst. Professor, Tobacco Specialist
mina_mila@ncsu.edu
Thomas Keever
Lead Forecaster / Meteorologist
thomas_keever@ncsu.edu