At 7 w.a.t, 50% roots samples detect R.solanacearum positive, roots black necrosis plant incidence increase rapidly, while stem show no obvious symptom.

• 移栽后第7周根部样品青枯菌检出率达到50%25左右、根部黑色坏死发病率开始快速上升，茎部无明显症状；