47th TWC, Tob. Work. Conf., 2016, abstr. 73

Management of spotted wilt in tobacco with Actigard 50WG + imidacloprid

VON WALDNER M.; BARNES T.; BEASLEY E.; CURRY S.; VARNEDORE T.; BERTRAND P.; MOORE J.M.
University of Georgia, Douglas GA USA

Tomato Spotted Wilt Virus has been the major cause of disease loss in Georgia tobacco in all but two of the past 25 years. Losses have been particularly high in and around Coffee County, in some cases exceeding 80 percent. A program of treating seedlings in the plant house with a foliar application of Actigard 50WG 7-10 days prior to transplant followed by a spray on/rinse off treatment of imidacloprid 2-5 days later is the only spotted wilt management option proven effective thus far. Trials conducted between 2000 and 2011 established a benchmark value of 52 percent as a mean or expected level of control of spotted wilt with this program. However, during these trials, in addition to expected farm to farm variation in percent control of spotted wilt, a distinct year to year variation was also apparent. Detailed trials conducted from 2009 to 2015 have clearly documented a year to year variation in control of spotted wilt with this program. The reasons for this annual variation are unclear at present but appear to be due to an annual variation in performance of imidacloprid. In spite of documented variation in spotted wilt control with the Actigard 50WG + imidacloprid seedling treatment program, it remains the only effective management tool for reducing disease loss in tobacco. (Reprinted with permission)