The North America Blue Mold Forecast Center in Raleigh, NC provided the tobacco industry and growers with timely documentation on the occurrences (new outbreaks) and potential for further spread (transport of fungal spores) of the pathogen (Peronospora tabacina) during the 1997 growing season. The Forecast Center is located within the Department of Plant Pathology at North Carolina State University. A total of 469 separate forecasts were prepared on 75 days from March through early August. Forecasts were posted on the World Wide Web each Monday, Wednesday, and Friday, and more often when necessary. The forecasts attempt to document new occurrences, gauge the potential for sporulation at the source, evaluate the chances of survival and depositition during long-distance transport of spores, and provide a risk assessment for each separate forecast. New reports and continuing status of disease are monitored daily via a Forecast Homepage Reporting network of coordinators in U.S. states, Mexico, and Canada. Coordinators are in daily contact with the Forecast Center and all other coordinators.
Blue mold occurred in nearly all the tobacco production areas of eastern North America in 1997. First report of blue mold in commercial tobacco was just northwest of Gainesville, Florida on April 23. The most active and widespread movement and development of the 1997 epidemic occurred from late May through mid-June in the mid-Atlantic states. With few exceptions, blue mold occurrences were dominated by metalaxyl-resistant strains of P. tabacina. Grower and industry confidence in and usage of the forecasts increased over the 1996 forecast year. Twelve of thirteen first reports by state could be explained by forecasting long-distance transport of spores correlated with favorable weather conditions for spore survival and infection.
| State/County | Date | Probable source (b) | Impact (c) |
|---|---|---|---|
| Columbia County, FL | April 23 | Cuba | ? |
| Grady County, GA | May 9 | Cuba | ? |
| Greene County, NC (flue-cured) | May 22 | N Fl/SW GA | .5-2.0 % avg |
| Maury County, TN | June 2 | unknown | ? |
| Lancaster County, PA | June 6 | Import of infected seedlings | ? |
| Lee County, VA | June 11 | S GA | ? |
| Horry County, SC | June 11 | E NC | ? |
| Madison County, NC (burley) | June 11 | S GA | ? |
| Anne Arundel County, MD | June 12 | E NC | ? |
| Christian County, KY | June 13 | W TN | ? |
| Hartford County, CT | July 9 | SE PA | ? (poss 50%) |
| Gallia County, OH | July 9 | S Appalachian Mntns | ? |
| Elgin County, Ontario, Canada | July 25 | Multiple | ? |
Web page last updated by Thomas Keever on 27 August 1997.