Field experiments were performed in 2010 and 2011 at Qingdao Experimental Farm. N. tabacum cv. NC89 plants were sprayed with 100-fold dilution CZ three times at 7-day intervals after transplanting.
Three replicates were arranged per treatment in a randomized block design, each consisting of forty plants in single-row plots. 200-fold Ningnanmycin dilution or water was applied to plants as controls. The tobacco field was drip-irrigated. All plants were examined for disease severity before flowering