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| First sighting of blue mold in U.S. tobacco, March 22, 2002, near Eldorado, Georgia. Two acre bed site destroyed the day the disease was discovered. Foliar and systemic blue mold present. (Click on images for expanded image) | ||
For
Additional Blue Mold Information
http://www.ces.ncsu.edu/depts/pp/bluemold/
(From the "2002 Georgia Tobacco Grower's Guide")
PLANT HOUSE DISEASE CONTROL
TABLE 1. BLUE MOLD, RHIZOCTONIA (DAMPING OFF & TARGET SPOT)
| Chemical and Formulation | Rate Per 1000 sq. ft. | Remarks |
|
Dithane DF |
0.5 - 0.9 oz | spray to run-off (3 increasing to 12 gallons per 1000 sq. ft.) every 5-7 days when plants reach dime size (0.5 - 1 inch). Apply after each clipping. |
BLUE MOLD IN THE FIELD
Blue mold caused by Peronospora tabacina is spread by spores carried long distances by wind. Ideal conditions for blue mold would be night temperatures above 50 o F, day temperatures about 70 o F along with fog, rain or dew to keep leaves wet.
Long distance spore movements are tracked by the North Carolina Blue Mold Forecast System. This system can give up to 48 hours warning of blue mold spore movement. This information can be accessed via the world wide web at: http://www.ces.ncsu.edu/depts/pp/bluemold/
These forecasts may be used to trigger treatment or intense scouting depending on the level of risk each individual wishes to assume. These forecasts are useful to predict first movement of blue mold into an area. Once blue mold is present, local weather conditions should be used to make further treat/don't treat decisions.
Table 2. Blue Mold Control
| Chemical and Formulation | Rate Per Acre | Remarks |
| Acrobat MZ (click below for label) http://www.cdms.net/ldat/ld751001.pdf |
0.5 - 2.5 lbs | Select Acrobat MZ rate and spray volume/acre from table below. To be effective Acrobat MZ requires total plant coverage. |
| Weeks of Growth After Transplant |
Rate of ACROBAT MZ |
Water Output |
| Recently Transplanted to 3 weeks after transplanting. | 0.5 | 20 |
| 3-4 weeks after transplanting (Knee High) |
1.0 | 40 |
| 4-5 weeks after transplanting (Waist High) |
1.5 | 60 |
| 6-7 weeks after transplanting (Chest High) |
2.0 | 80 |
| 7 weeks after transplanting and beyond (Shoulder height up to topping) |
2.5 | 100 |
Note: Above directions are for dilute sprays. If concentrate sprays are used, adjust rate and volumes proportionally, e.g. for mist blows, use 2X concentrate and ½ the spray volume.
Begin applications when the Blue Mold Advisory states that conditions favor development of blue mold, and before the onset of disease infection. Continue applications on a 5-7 day spray schedule until weather conditions favoring infection and sporulation decrease. Discontinue sprays when and if the threat of blue mold subsides. Restrictions (Field Applications): DO NOT exceed 2.5 lbs/acre per application. DO NOT exceed 10 lb/acre of ACROBAT MZ per season. In flue cured tobacco, DO NOT spray after the appearance of first button, or within 21 days of harvest.
| Chemical and Formulation | Rate Per Acre | Remarks |
| Actigard 50 WG (click below for label) http://www.cdms.net/ldat/ld3UC002.pdf |
0.5 oz | Apply Actigard any time after tobacco reaches 18 inches high. Make a second application 10 days later |
| Actigard is not a traditional fungicide. Actigard induces a disease resistance mechanism in some plants including tobacco. It takes 5-7 days after an Actigard application for the disease resistance process to become fully effective. | ||
