Long-term storage and survival structure of three species of <Emphasis Type="Italic">Phytophthora </Emphasis>in water

 Cultures of Phytophthora cinnamomi, P. parasitica, and P. palmivora remained viable in water at room temperature for periods ranging from 6 to 23 years. The colonies that developed from the stored cultures were thin-walled and spherical, ranging from 19.2 to 30.0 μm in diameter. The survival structures are thought to be small chlamydospores produced in the absence of adequate nutrition and aeration. Received: October 7, 2002 / Accepted: January 8, 2003 Acknowledgment I thank Dr. Michael L. Parsons for assistance in preparing the photograph.     

烟草黑胫病菌培养特性的研究

研究了云南烟草黑胫病菌在不同培养基、不同温度的生长情况及不同菌龄与不同诱导时间孢子囊的产生数量。结果表明,菌株在8种供试培养基中,以燕麦培养基和选择性培养基上菌落生长最好,其次为胡萝卜培养基,在番茄汁和马铃薯培养基上生长最差。同一菌株在不同培养基上产孢量不同、产生的孢子囊大小亦有所不同。05P226菌株在玉米培养基上产孢量最高;05P55菌株在燕麦培养基上产孢量最高,在番茄汁培养基上产生的孢子囊最大,而05P62菌株在燕麦培养基上产孢量最高,在烟叶汁培养基上产生的孢子囊最大。在30℃菌丝生长速率最高,其次为28℃,以35℃生长最差。供试3个菌株间生长差异显著,以05P226生长最好,05P55菌株次之,05P62生长最差。05P226、05P55菌株皆以培养14d、诱导72h产孢量最高,最适宜试验中产孢培养。     

七种杀菌剂对寄生疫霉菌的毒力测定试验

本试验对潺菜病叶进行了组织分离,经过纯化鉴定病原菌为寄生疫霉(Phytophthora parasitica Dastur)。试验使用了七种杀菌剂采用了含毒培养基生长速率法来测定对寄生疫霉的抑制效果,试验结果表明：药后48h,百菌清的EC₅₀值为13.60mg/L,毒力指数较大,对寄生疫霉菌抑制效果非常显著;恶霜锰锌和代森锰锌的EC₅₀值为16.99和28.62 mg/L,抑制效果较显著;甲霜锰锌、霜霉威和烯酰吗啉的EC₅₀值分别为为56.23mg/L、56.23mg/L和60.71mg/L,效果一般;二氯异氰的EC₅₀值为319.21mg/L,毒力效果较差;药后24h各药剂对寄生疫霉的抑制效果与药后48h抑制效果相似。     

栗疫病研究进展

全面综述了栗疫病的研究进展,包括栗疫病的发生和为害性、症状、病原菌及其弱毒力、寄主植物、病害循环、发病条件和防治等方面所取得的成就和发展趋势,并就某些问题提出作者的观点     

一种简便易行的栗疫病菌单孢分离方法

介绍了一种分离栗疫病菌单分生孢子的简便易行的方法。此方法可以排除菌丝段的干扰,也适用于分生孢子器中产生微小分生孢子的其他真菌。     

不同来源的板栗栗疫病菌致病性差异研究

为了探索我国板栗疫病发生区域病原菌之间的致病力差异,收集46株来源于我国6省18个县（市）的板栗疫病菌株,通过毒力比较和对同一株板栗枝条的接种试验,测定不同地域菌株间的致病性差异。结果表明,不同地域来源的栗疫病病原菌的致病性具有显著差异,其中,北京怀柔、四川眉山等地来源的栗疫菌致病性最强,属于强毒力菌株,而陕西镇安来源的栗疫菌致病性最弱,湖北武汉和宜昌的栗疫菌致病性居中。     

In vitro and in vivo antifungal activity of Satureja cuneifolia ten essential oil on Saprolegnia parasitica strains isolated from rainbow trout (Oncorhynchus mykiss,Walbaum) eggs

In the present study, the chemical composition and the antifungal properties against Saprolegnia parasitica (in vitro and in vivo) of the essential oils of thyme (Satureja cuneifolia) from Mediterranean region of Turkey were evaluated for the first time. The composition of oils was analysed using gas chromatography/mass spectrometry (GC/MS). The major constituents of oil of S. cuneifolia were cavracrol (46,84%) and cymene (16.90%). Antifungal effects of S. cuneifolia essential oil against S. parasitica strains (A1 and E1) were detected by disc diffusion and tube dilution assays. The antifungal effect of S. cuneifolia was determined to be stronger against S. parasitica E1 isolate (MIC 50 μL mL^?1, MLC 250 μL mL^?1) compared with S. parasitica A1 isolate (MIC 50 μL mL^?1, MLC 500 μL mL^?1). Following in vitro assays, effective doses of S. cuneifolia for disease control in rainbow trout eggs experimentally infected with S. parasitica were investigated. For this aim, infected eggs were treated with the essential oil (0, 5, 10, 20 and 50 ppm) during incubation period (21 days) after fertilization. Formalin (5 mL L^?1) was used as positive control. Hatching rate of eggs at the end of incubation period were calculated. The highest hatching rates were recorded in S. parasitica E1 strain at 5 and 10 ppm concentrations of S. cuneifolia and in S. parasitica A1 strain at 10 and 20 ppm (P < 0.05).     

烟草黑胫病菌拮抗细菌的筛选与鉴定

从烟草根际土壤分离到107个细菌分离物,通过室内平板对峙培养筛选,筛选到13株对烟草黑胫病菌有拮抗作用的菌株,其中,LZ-7菌株的室内平板抑菌效果最好,抑菌圈直径达27.82 mm。经盆栽试验,LZ-7、A3控病作用较好,防治效果分别达59.12%和55.84%。通过16 S rDNA序列测定与分析,LZ-7与Bacillus pumilus的同源性为99%,初步鉴定证明该菌株属于短小芽孢杆菌。     

木霉菌防治烟草黑胫病研究进展

黑胫病是烟草生产上的重要土传病害之一,广泛分布于各个烟草种植区。综述了利用木霉菌防治烟草黑胫病的菌株筛选、防治效果、拮抗机制的最新进展,为烟草黑胫病的生物防治提供了参考。     

锥栗溃疡病病原菌及其生物学特性

锥栗溃疡病是近年来在福建省锥栗栽培区建瓯、南平等地发现的一种危险性病害。经鉴定,病原菌为寄生内座壳菌。病原菌的菌丝在PDA培养基上生长良好,培养7～10天后形成大量分生孢子,但培养30天后仍不形成子囊。菌丝生长景适温度为24～26℃,最适pH值为5～6。在96.1％高湿条件下,分生孢子萌发率最高,低于50％相对湿度,则完全不萌发。研究结果表明,锥栗溃疡病的症状、病原菌形态特征及其生物学特性与检疫病害板栗疫病一致,所以该病害必须严格控制,避免扩散流行成灾。