兰州百合叶枯病病原菌形态特征及生物学特性研究

Studies on Morphology and Biological Characteristics of Botrytis elliptica (Berk.) Cooke Causing Foliage Blight of Lilium davidii Duch. var. unicolor (Hoog) Cotton

百合叶枯病是兰州百合生产中的主要叶部病害,在多雨年份危害尤其严重。由于2012年6～8月降水偏多,兰州百合叶枯病大发生,至8月中旬重病田兰州百合枯死株率达50%～70%,部分田块兰州百合地上部全部枯死。经致病性测定和形态特征比对,将兰州百合叶枯病病原菌鉴定为椭圆葡萄孢Botrytis elliptica(Berk.)Cooke。病菌菌丝在5～30℃均可生长,适宜生长温度为20～25℃;30℃菌丝生长受抑制,菌丝褐化;35℃菌丝不生长,但在35℃培养7d后转放至20℃培养,可于5d后恢复生长。菌核产生温度为5～25℃,菌核的产生时间、位置及大小在不同菌株、不同培养温度及同一菌株的不同重复间均存在较大的变幅。性孢子稀少至极丰富。分生孢子在自来水中20℃条件下3～5h即开始萌发,15h萌发率达50%～99%,通常萌发产生1～2个芽管,并在孢子中间形成0～2个隔膜。

Botrytis foliage blight is a main disease of Lilium davidii Duch. var. unicolor(Hoog) Cotton in central region of Gansu Province.It becomes a devastating disease in rainy years.In June-August of 2012,due to the heavier rainfall than the usual years,botrytis foliage blight of Lilium davidii Duch. var. unicolor(Hoog)Cotton outbroke severely.The wilting plants reached to 50%- 70% in serious affected fields in mid-August.In some fields,almost all of the plants were killed. The pathogens(strain lily-1 and lily-2)were isolated from diseased leaf of Lilium davidii Duch. var. unicolor(Hoog)Cotton.They were identified as Botrytis elliptica(Berk.)Cooke,according to Koch’s rule and morphology characteristics comparison.The mycelium can grow under 5-30 ℃,and the optimal temperature is 20-25 ℃. Mycelial growth is suppressed and the mycelia turned brown at 30 ℃.Mycelia stops growing at 35 ℃,but it can recover growing after being cultured 7 days at 35 ℃ and then being transferred to 20 ℃ for 5 days culture. The temperature for sclerotia forming is 5-25 ℃.There are bigger variations in sclerotia forming time,position and size in different bacterial strains,different culture temperatures or different repeats in the same bacterial strain.Sexual spores are rare or extremely abundant.Conidia begins to germinate at 20 ℃ in 3-5 hours.The germination rates can reach 50%-99% in 15 hours.Conidia produces 1-2 germ tubes usually,and forms 0-2 septa in the middle of conidia.