Environmental spots (Weather Fleck)
As the 2024 tobacco season advances into July, the overall crop remains robust in most locations. Recently, we experienced cases of weather fleck occurrence.
Weather fleck, a leaf disorder in flue-cured tobacco, is caused by air Pollutants, primarily ozone (O3), a secondary pollutant in the atmosphere. Ozone damages leaf tissue, resulting in small, irregularly shaped spots that begin as black, turn brown, typically less than 4 mm (1/8 inch) in diameter. The most serious losses occur just before or during the early stages of harvest, about 4-6 weeks after transplanting, when the lower leaves are maturing, though symptoms can appear at any growth stage. This disorder often follows prolonged rainy periods and during the active growth phase of tobacco when tissues are particularly succulent.
Figures 1 and 2 severe weather flecks symptoms resulting from ozone (O3) exposure.
Management
Current control measures for Weather Fleck in tobacco involve cultural practices and selecting tolerant varieties. Cultural practices like proper plant spacing, appropriate irrigation, well-balanced fertilization, early topping, and sucker removal help produce leaves that are less susceptible to Weather Fleck.
Post prepared and sent by Canadian Tobacco Research Foundation
Mailing Address: CTRF, P.O. Box 322, Tillsonburg, ON N4G 4H5
Telephone: 519-842-8997
Web Address: http://ctrf1.com