[Scientific Papers] http://www.scipapers.com    2007-11-16  

Timing of application of Actigard and Admire for TSWV management in tobacco

Csinos AS¹, Laska JE ¹, Mullis SW ¹, Stephenson MG ², LaHue SS ³, Nischwitz C ¹

¹University of Georgia, Dept. of Plant Pathology, Coastal Plain Experiment Station, Tifton, GA 31794

² University of Georgia, Dept. of Crop and Soil Science, Coastal Plain Experiment Station, Tifton, GA 31794

³ University of Georgia, Field Research Services, Coastal Plain Experiment Station, Tifton, GA 31794

Correspondence: csinos@tifton.uga.edu; nisc5708@uidaho.edu

Tomato spotted wilt virus (TWSV) continues to be a serious problem in tobacco in Georgia. In 2003, about 40% of the tobacco crop in Georgia was infected. Both Actigard and Admire have shown to be effective against TWSV and reduce incidence. In this study the effect of different combinations and rates of Actigard and Admire as well as pre-plant and post-plant applications of the chemicals on TWSV incidence were tested. The treatments included an untreated control as well as a transgenic standard. A randomized complete block design was used consisting of single row plots that were repeated five times using K-326 fluecured tobacco. The plots were set up in fields at the Coastal Plain Experiment Station. Of the 16 different treatment combinations tested, twelve significantly reduced the percentage of symptomatic plants. The lowest percentages of symptomatic plants and of plants killed by TWSV were achieved by pre-plant treatments with Actigard and Admire plus post-plant treatments with Actigard that included an application 28 days after planting. Several treatments that included post-plant applications resulted in significantly higher yields compared to greenhouse application of Actigard and Admire alone. The two best treatments which consisted of pre-plant applications of Actigard and Admire and either one (28 days after planting) or three post-plant applications of Actigard were within 300lbs./A yield difference compared to the non-diseased transgenic standard and had over 1300lbs./A higher yield compared to the untreated control.