FORECAST DISCUSSION: Wednesday, April 23, 1997 - *** First report of blue mold in U.S. production areas !!! *** The State Blue Mold Coordinator in Florida reports actively sporulating blue mold in old plant beds 12 miles NW of Gainesville. Details aren't yet available but are forthcoming. This location will be added as a source starting today. To make room in the forecasting schedule the San Andres Tuxtla, Mexico source will be dropped from the rotation. The Tapachula, Mexico source may also need to be dropped but will be kept in as long as possible. We encourage growers in those areas to monitor their local conditions as best they can, and we will try to provide guidance for those two locations if situations appear especially dangerous.
*** Please note *** the changes in the descriptions of the "Threats" and the "High Risk" areas immediately below. It appears that your Forecaster has inadvertantly caused some confusion, even for the person who suggested the improvements! By way of explanation.....
Threats will always refer to sources of blue mold. Descriptions will typically refer to the degree of potential disease development from that source and/or the range of that threat. Frequently used words include "little" or "minimal", "mild", "moderate", "serious", "localized", "short-range", or "long-range".
Risk will always refer to the likelihood of blue mold development in tobacco production areas. It describes the chances of disease development at a particular location when all the factors of blue mold development are taken into account (sporulation, spore release, survival during transport, deposition under conditions favorable for infection - 'effective deposition'). Degree of risk will usually be phrased as "low" or "slight", "moderate", and "high". "Moderate" risk covers a large range of possibilities; this is because many of the weather conditions that affect the factors for disease development (ex: amount of cloud cover, chance of precipitation, intensity and areal coverage of precipitation) cannot be forecast precisely. "High Risk" is a term used ONLY when ALL the factors for blue mold development appear VERY LIKELY to happen. Sometimes, if the quality of the forecasts makes it possible, the risk assessment may be phrased as "strongly moderate" or "weakly moderate" as an aid in interpretation.
Using the forecasts of Monday the 21st as an example, Pinar del Rio was listed as a "serious" threat, but there were no "High Risk" areas. Conditions appeared favorable for disease development. However, there was not enough known about the possibilities for deposition later, or the amount of cloud cover for the next day's release, to characterize the situation as a "high risk" to anyone. The risk in this case was probably one of "strongly moderate risk" rather than "weakly moderate risk", and perhaps should have been worded that way.
In short.....a hungry lion and a rabid spaniel are both serious threats, but one places you at more risk than the other. My thanks to Tom Melton at NCSU for both his suggestions and his feedback regarding this issue. To the forecasts..........
No long-range threats are present for today's forecast. The only possible exception may be a very slight risk to the southern edges of central Florida's production areas. There are a few areas that may see some localized development, however. These include Gainesville, FL; Pinar del Rio, Cuba; and Uvalde, Texas. Spore release from the Gainesville source was hindered today because of the widespread rain, which persisted long enough to bring down any spores that happened to get airborne. This area is at low to weakly moderate risk. Some localized disease development is possible near the Cuban source tomorrow, and there's a moderate risk of blue mold from Thursday's release in the hill country of Texas near Uvalde. Looking to the weekend, conditions in the SE U.S. will be generally unfavorable for disease development, but a vigorous low pressure system moving through the southern plains may provide conditions suitable for blue mold in S Texas. TK
SERIOUS SOURCE THREATS: None
HIGH RISK GROWING AREAS: None
***** NOTE: These forecasts/outlooks only apply to disease development from airborne transport of spores!!! We do not have the capability to ascertain blue mold development by other means, such as transplanting of infected seedlings, nor will we attempt to do so. Please consult the Extension Service personnel in your area if you have concerns about these matters! *****
This service is provided by the North Carolina State University departments of Plant Pathology and Marine, Earth, and Atmospheric Sciences.
Web page last updated by Thomas Keever on 23 April 1997.