芦笋茎枯病病原菌的订正

<正> 芦笋(Asparagus officinalis L.)又名石刁柏,百合科天门冬属的食用种,其嫩茎(笋)加工制罐或直接速冻后出口,颇具发展前景。60—70年代,根据国际市场需要,台湾、福建、浙江、山东、江苏,四川、安徽、辽宁、江西、上海及天津等省市大面积栽培。由于茎枯病发生普遍,危害严重,不少芦笋生产基地面临萎缩和毁田威胁。本文报道该病病原菌分类地位研究结果。(一)病原1884年,Saccardo将芦笋茎枯病病原菌定为Phoma asparagi Saccardo后,虽曾有过异议,却一     

玉蜀黍丝核菌的鉴定特征

在研究四川省玉米纹枯病菌系时,获得23个RhizoctoniazeaeVoorhees菌株。该菌菌丝形态与R.solaniKuhn相似;菌丝细胞含3个以上椭圆形细胞核;隔膜具桶孔,桶孔周围的隔膜肿体（septalswelling）与隔膜板垂直,两端不再膨大外延;菌丝生长较快,在PDA平板26℃下培养,每24小时菌落直径增长33．2～39．1mm;菌丝与苯酚相互作用后,着色较深,呈深褐色。菌核初期为白色或奶油色,成熟后为红褐色;常散生于基质内,少数着生在基质表面和培养皿的内壁上;球形或近球形,直径0.25～1．0mm;结构致密,无菌环和菌髓分化,表面较光滑。223个R.zeae菌株均与Oniki等建立的WaiteacircinataWAG－Z标准菌株发生融合,但与R.solani的融合群标准菌株均无融合反应。R.zeae对玉米的致病性较强,稍弱于玉米纹枯病主菌系R.solaniAG－1－IA,其病斑多半不连续,颜色较深,也可0侵染果穗引致穗腐并在苞叶上产生大量红褐至黑褐色的小菌核。     

马铃薯晚疫病菌卵孢子萌发的初步研究

描述了马铃薯晚疫病菌卵孢子萌发的方式并研究了菌株组合、卵孢子形成时间、在琼脂培养基上培养时间及光照对卵孢子萌发的影响,结果表明不同菌株组合卵孢子萌发率为0—7.2%,对峙培养20天后形成的卵孢子的萌发率最高达8.7%,在琼脂培养基上培养25-30d 萌发率最高达11.4%,卵孢子形成时黑暗及在琼脂培养基上萌发时光照萌发率最高达11.8%。     

湖北省玉米纹枯病病原丝核菌的种类和致病性*

从湖北省9个主要玉米产区采集玉米纹枯病标样,分离得到55个丝核菌菌株。融合群和致病性测定表明,这些分离菌分别属于AG1—IA、AG4、AG5、AGA、AGB(0)、AGE和WAG-Z等7个丝核菌融合群,其中AG1-IA是优势融合群,占分离菌株总数的61.82%,分布范围也最广。在致病性方面,除AGA不致病外,其它6群均致病,其中AG4致病力最强,AG1-IA次之,AG5最弱。研究同时表明,同一融合群内不同菌株致病性有差异,并且同一菌株对不同玉米自交系的致病力的强弱表现不完全一致。     

SEEDLING BLIGHT OF SUGAR-CANE-A NEW DISEASE CAUSED BY HELMINTHOSPORIUM SACCHARI BUTLER

The fungus Helminthosporium sacchari Butler, known to be the cause of eye spot, a common air-borne disease of sugar-cane leaves, is now shown to be the cause of an undescribed seed-borne disease of sugar-cane seedlings. It is therefore suggested that the disease should be renamed eye spot and seedling blight of sugarcane.
The symptoms of seedling blight are described, and the pathogenicity of the fungus to sugar-cane seedlings is confirmed. Incidence of seedling blight is shown to be markedly affected by the growing conditions, and disease-escape is common. The two most important factors predisposing seedlings to attack appear to be (i) the relative humidity of the atmosphere, and (ii) the occurrence of a check to the continuous growth of the seedlings.
With the discovery of the existence of seedling blight, eye spot assumes a particular significance in plant-breeding plots, because it may be responsible for the loss of sugar-cane seedlings, any one of which is potentially a desirable new variety.     

板栗疫病菌致病力分化的研究

中国板栗(Castanea mollissima Blume)对板栗疫病菌(Cryphonectria parasitica(Murr.)Barr)具有强的抗病力。但近十多年来,我国许多省份均发现有板栗疫病,据调查,广西有19个县市存在栗疫病,有的地方发病还相当严重。为了解释疫病发生的上述情况,并为生产和该病菌的更深入研究提供指导,作者在广西桂林、南宁、柳州、梧州、河池等地收集菌株,对疫病菌致病性的分化进行了研究,现将结果报道如下。 1 材料和方法 1.1 毒力参照菌株 法国已知弱毒株EPF为毒力参照株。 1.2 栗疫病菌的采集、分离和单孢纯化 1.2.1 标本采集:1988年12月～1989年6月,采自广西桂林、南宁、柳州、梧州、河池等地板栗病株。 1.2.2 菌株分离和纯化:将病枝或病树皮,用经灯焰灼烧过的刀片削去表皮,取坏死内皮约5×5mm^2,压于PDA上,28℃,光照培养,产孢后用微块法进行单孢纯化。 1.3     

THE CONTROL OF FUSARIUM BLIGHT IN OAT SEEDLINGS WITH ANTAGONISTIC SPECIES OF CHAETOMIUM

Forty-seven isolates representing twenty-seven species of Chaetomium were tested for their ability to control seedling blight of oat seedlings caused by Fusarium spp., chiefly F. nivale (Fr.) Ces. In pot tests the majority of the isolates were ineffective, but certain isolates of Chaetomium cochliodes Pall, and C. globosum Kunze gave a large measure of control and were as effective as an organic mercury seed dressing. Control of disease was also obtained when living material was attached to the surface of oat seed and when infested seed was soaked in cell-free filtrates from cultures of isolates which reduced disease in vivo.
Substantial control of disease was obtained when infested seed was sown in soil to which cultures of C. cochliodes had been added 10 months previously. This antagonist was able to grow through unsterile soil in the presence of certain added substrates.
The results of pot experiments were confirmed in field experiments.
Isolates of Chaetomium which controlled disease in pot and field experiments were not strikingly antagonistic to Fusariirm nivale in pure culture on agar media.     

云南省水稻纹枯病菌系研究*

将来自云南省20多个县市的水稻纹枯病标样130多份,选代表性的标样分离得到54个菌株。按菌丝融合测定法, 将54个菌株分为5个菌系:R.solani的AG-1 IA ,AG-1 IC,AG-6GW 以及双核丝核菌的AG-Bb, AG-I II。经致病性测定表明,该菌系对水稻、玉米、小麦的苗期及成株期的致病性有显著差异。其中AG-1 IA, AG-1 IC, AG-I II 的致病力最强, AG-6GW的最弱。对这些菌系的酯酶同工酶进行比较研究发现,不同菌系间均存在明显差异, 而同菌系不同菌株间却具一致性。由此说明,按菌丝融合与否区分丝核菌种群较之现行的其它分类法更能反映其遗传本质和亲缘关系。