聚合草青枯病的发生规律及病原菌的研究

 高产优质饲料聚合草的青枯病,是七十年代发现的一种细菌性病害,分布在我国南方诸省,六至七月份为流行期,发病率一般为10~30%;严重地区高达90%以上,可形成毁灭性病害。该病侵害植株的维管束,使叶片青枯萎蔫和根部腐烂而死亡。对分离自病根的细菌,经形态、培养特征、生理生化特性、血清学反应及致病性等的鉴定,确认为青枯假单孢菌(Pseudomonas Solanacearum Smith),属于生理小种1(Race 1),生物型Ⅲ(BiotypeⅢ)。所致病害为聚合草青枯病。

ON THE DEVELOPMENT,EPIPHYTOTICS AND IDENTIFICATION OF THE CAUSAL ORGANISM OF THE BACTERIAL WILT OF SYMPHYTUM SP.

The bacterial wilt of Symphytum sp.caused by Pseudomonas solanacearum Smith occurred in the 1970s.It was widely distributed in provinces of south China and the general incidence ranging from 10 to 30%.In some areas,the disease is very serious;sometimes it destroys the crop totally.The main symptoms of the disease consists of wilt followed by death and the brown stain formed in the vascular bundles of the infected roots.If the infected roots are cut across and gently squeezed,cream-like drops of sticky liguid full of bacteria exude from the severed bundles.At the later stage of the disease,the infected roots rotted entirely.
The causal organism is Gram negative rod;cells show bipolar staining,ca.0.6 to 0.9×1.0 to 2.0 micron meter.It does not form spore and is nonencapsulated.The organism is motile,with 1 to 4 polar flagella.It grows at 10 to 39℃ and is able to be initiated within the pH nang from 5.0 to 8.5 The organism produces acid from hexose,disaccharides,trihydric alcohols,hexose alcohols,cycloexanhexol except pentose and salicin.
Accordingly,it is evident that the morphological,physiological,biochemical,serological characteristics and pathogenicity of the organism are identical with those of pseudomonas solanacearum Smith,and the organisum is abiotype of its physiological race 1,designated as Biotype Ⅲ.