Tobacco growers with recently topped plants and those still needing to be topped should take measures to prevent blue mold development, said Bob Pearce, extension tobacco specialist with the University of Kentucky College of Agriculture, Food and Environment.

UK plant disease diagnosticians confirmed blue mold on burley tobacco from Mason, Lewis and Clay counties in the past several days. The disease was found on multiple leaves with older lesions and new lesions with active spores. Due to the locations of the finds, tobacco growers east of Interstate 75 should make preventative fungicide applications to plants that have been topped within the past few days or have not been topped yet. Tobacco that has been topped for some time is not at a great risk for disease development and does not need a fungicide application.

“After the tobacco is topped, physiological changes occur in the leaf to make it more tolerant to the disease,” Pearce said.

Weather conditions during the past week were favorable for the development and spread of blue mold.

Two fungicides, Quadris and Revus, can help prevent blue mold. Application guidelines are available in the UK plant pathology Fungicide Guide for Dark and Burley Tobacco located at http://www2.ca.uky.edu/agcollege/plantpathology/ext_files/PPFShtml/ppfsagt8.pdf or at local offices of the UK Cooperative Extension Service.

Growers who suspect they have disease development should submit samples to their local agriculture and natural resources extension agent for positive identification.