Varying fungicide application methods and cultivars for black shank control in burley tobacco in Virginia, 2007

摘要

Experimental plots consisting of single rows, each 30 ft long, were established on 48-inch centers in a naturally infested tobacco field at the Southern Piedmont Agricultural and Research Extension Center (SPAREC) in Nottoway County, Virginia. The experiment was conducted using a split plot design with 4 replications. Main plots consisted of soil fungicide application methods, which involved comparing broadcast sprays with use of a single, narrow-angle (4004 or 11004 air induction) spray tip/row to apply the product in a 12 inch band. Alternatively, a single solid cone spray tip was used toapply fungicide overtop of plants in sufficient spray volume that the spray solution would “rundown” plant stems to the soil surface surrounding the base of each plant. Main plot fungicide treatments were separated from each other by a singleborder row on each side. Subplots consisted of the burley cultivars NC 7, TN 90, and NCBH 129, which were mechanically transplanted on 23 May with a 20-22 inch plant spacing within the rows. First cultivation treatments were applied on 1 June(air temperature 89oF, soil temperature 87oF, relative humidity 46%, wind speed 1 mph, average spray volume 43 gal/A ), and layby treatments were applied on 26 June (air temperature 84oF, soil temperature 82oF, relative humidity 54%, windspeed 3 mph, average spray volume 56 gal/A) with a tractor mounted PTO-driven sprayer. The trial was laid-by on 27 June. Fertilizer and cultural pest practices followed recommendations of Virginia Cooperative Extension. Initial standcounts were made on 24 May. Disease counts were made on 12 and 27 Jun, 11 and 23 Jul, and 6, 20, and 31 Aug. Weather conditions remained dry throughout the growing season. The experiment was irrigated on 10 Jul with approximately 1 inch of water. The trial was harvested on 31 Aug, but yield and quality data are not yet available.