1.Preparation of CZ powder and TMV suppression
Pseudomonas fluorescens strain CZ was isolated from tobacco field soils at Qingdao Experimental Farm and stored at 4 C. The stocked bacteria culture was incubated in nutrient broth medium (10 g peptone, 3 g beef grease, 5 g NaCl, 1 g glucose) or in a mixture medium in a microbial fermentor at 28 °C for 72 h to prepare CZ sub-cultures. Pseudomonas fluorescens strain CZ cultures in mixture medium were mixed with silica white at a ratio of 6 ml:1 g and spray dried. Silicone surfactant)2% was added before use.