Identification And Biological Characteristics Of Pathogen Of Tobacco Gray Mold In Fujian,China

The tobacco grey mould disease was investigated in Fujian during2009-2011,and it was serious in localized place. The pathogen identification and biologicalcharacteristics were studied, and the results were listed as followed:1. Pathogenic classification status of tobacco grey mould disease was confirmed.According to the study of the colony morphology, culture characteristics,pathogenicity and host range, the pathogens,isolated from tobacoo,were identifiedas Botrytis cinerea.2. It was confirmed that the morphology and biological difference was found indifferent pathogens. There was significant differrence in colony, conidiophore andsclerotium morphology. These isolates were divided into six populations, accordingto morphology difference.The results of the pathogenicity test showed that there was the pathogenicitydifference in total17isolates. According to average diameters of the lesions caused bythe pathogens, the isolates were divided into three different groups:strong,intermediate and weak virulent. The results also showed that the difference ofpathogenicity to tobacoo leaves was not obviously related to locality of isolates, thepathogeincity of isolates in same place and same tobacco planting area was alsodifferent.The results of studies on biological characteristics of17strains suggested thatbiological characteristics were different, and were not related to pathogenicity andcultural characteristics.3. The infection cycle and incidence condition of tobacco grey mould wereinvestigation in Fujian. It is discoveried that tobacco gray mold disease characteristicswere as followed:1) The infection of this disease on leaves is extremely high.Especially the metabolic weak old leaves, the lower part of the plant leaves and theleaves close to the ground can be easily infected.2) Disease spot mainly concentratedon the blade in front, gray or near the part of the gray. The field investigation foundthat grey mould disease occurred mainly from April to June, and in some area this disease was serious, even on harvest leaves grey mould disease can also be founded.Cultivars resistance test showed that the mainly cultivars' resistance to grey mouldin Fujian was weak.