在云南省昆明市晋宁区高山杜鹃盆花种植基地发现枯梢病,田间发病率达20%以上。发病植株顶梢枯死,茎杆溃疡,最终枯萎死亡。对病原菌进行组织分离培养和致病性测定,结果表明,病原菌菌落初期白色,后期呈灰黑色;分生孢子器球形,黑色;分生孢...在云南省昆明市晋宁区高山杜鹃盆花种植基地发现枯梢病,田间发病率达20%以上。发病植株顶梢枯死,茎杆溃疡,最终枯萎死亡。对病原菌进行组织分离培养和致病性测定,结果表明,病原菌菌落初期白色,后期呈灰黑色;分生孢子器球形,黑色;分生孢子单胞,近椭圆形至纺锤形,大小为(17.2～32.8)μm×(4.7～7.8)μm。以ITS通用引物对病原菌基因组DNA进行扩增并测序,同源性比对显示其与小新壳梭孢(Neofusicoccum parvum)的一致性达99%,结合形态学鉴定结果,确定该病原菌为小新壳梭孢。病原菌的最适生长温度为25℃;p H 5～7时菌丝生长加快,pH 7时最适于菌丝生长;以蔗糖为碳源、硫酸铵为氮源时菌丝生长最好。不同高山杜鹃品种对小新壳梭孢的抗性存在差异,18个品种中免疫品种2个,高抗品种2个,抗病品种3个,中感品种3个,感病品种4个,高感品种4个。展开更多
Unusually high levels of dieback have recently been reported in sugar maple, Acer saccharum Marsh., in Upper Michigan, and a network of plots was established to determine the extent and factors associated with the die...Unusually high levels of dieback have recently been reported in sugar maple, Acer saccharum Marsh., in Upper Michigan, and a network of plots was established to determine the extent and factors associated with the dieback. A possible contributor to this dieback is sapstreak disease caused by Ceratocystis virescens (Davidson) Moreau. Unhealthy trees with considerable crown dieback were evaluated across the western Upper Peninsula, MI to determine the prevalence of the sapstreak fungus using a minimally destructive sampling technique. Approximately 8% of 90 trees sampled were sapstreak positive and approximately 10% of trees were positive at one site that had recently been harvested. While the high levels of maple dieback present in these forests appear not to be directly caused by widespread sapstreak disease, the occurrence of sapstreak may be significantly impacting trees at some locations. However, even when present on a low number of trees, the biointeraction of sapstreak and decay rates from other fungi could be important for future tree mortality and value to the forest industry. Therefore, the effect of two sapstreak fungal isolates on the amount of decay caused by two common maple white rot fungi, Trametes versicolor (L.:Fr.) Pilat. And Irpex lacteus (Fr.:Fr.) Fr. was tested in the laboratory. Sugar maple wood blocks were precolonized by two native isolates of C. virescens followed by inoculation and incubation with decay fungi. Mean percent weight loss of blocks by white rot decay fungi ranged from 39% to 55%, but decay rates were not significantly affected by the presence of the sapstreak fungus.展开更多
Today,shisham plantations in Punjab,Pakistan face major constraints,especially dieback disease.This article reviews the multidisciplinary team work by forest and plant pathologists and economists to resolve the confus...Today,shisham plantations in Punjab,Pakistan face major constraints,especially dieback disease.This article reviews the multidisciplinary team work by forest and plant pathologists and economists to resolve the confusions in the pathology of dieback disease.It is intended to be of practical use to the foresters and plant pathologists reporting on this issue.展开更多
In vitro Kirby-Bauer disc-diffusion assays coupled with bio-imaging software techniques were used to assess native forest dwelling “fairy ring” forming fungi (Clitocybe nebularis) and co-habitant forest tree-root co...In vitro Kirby-Bauer disc-diffusion assays coupled with bio-imaging software techniques were used to assess native forest dwelling “fairy ring” forming fungi (Clitocybe nebularis) and co-habitant forest tree-root colonising non pathogenic, antibiotic producing bacteria (Bacillus licheniformis, Bacillus pumilis) for their antagonism towards Japanese larch dieback oomycetes phytopathogens which also affects ornamental alternative hosts. The aqueous extracts of C. nebularis exhibited the highest clearance (inhibitory) zone of 21.4 × 105 pixels = 573%) against Phytophthora ramorum than growth/clear zone Cartesian integrates recorded in untreated (control) disc (3.7 × 105 pixels = 100%) over 3-day incubation. The fairy ring fungal extracts also exhibited substantive antagonism against P. kernoviae (147%), P. lateralis (347%) and a solanaceous crop infecting P. infestans (86%). Quite encouragingly, the soil oomycete phytopathogen P. ramorum was inhibited strongly (mean ~ 177%) by both forest bacilli. Aqueous extracts of non-forest antifungal herbaceous plants (garlic and elderberry) expressed similar inhibitory effects (mean ~ 70%). A seaweed fungal elicitor component fucoidan showed moderate levels (mean ~ 85%) of antagonism against P. ramorum, P. kernoviae, P. lateralis and P. infestans. The results in this in vitro study highlight the intensity and vigor of antagonistic forest microflora and non-forest herbaceous antifungal agents such as garlic and other plant extracts as serious candidates for suppression of the oomycete Phytophthora pathogenic fungi in forest soils. This study calls for urgent scoping and impact assessment studies in pot experiments and mini-plot forest trials to gauge the fitness of these natural resources for field level potential biotechnological applications to combat the devastating dieback disease in the native woodlands and horticulture.展开更多
文摘在云南省昆明市晋宁区高山杜鹃盆花种植基地发现枯梢病,田间发病率达20%以上。发病植株顶梢枯死,茎杆溃疡,最终枯萎死亡。对病原菌进行组织分离培养和致病性测定,结果表明,病原菌菌落初期白色,后期呈灰黑色;分生孢子器球形,黑色;分生孢子单胞,近椭圆形至纺锤形,大小为(17.2～32.8)μm×(4.7～7.8)μm。以ITS通用引物对病原菌基因组DNA进行扩增并测序,同源性比对显示其与小新壳梭孢(Neofusicoccum parvum)的一致性达99%,结合形态学鉴定结果,确定该病原菌为小新壳梭孢。病原菌的最适生长温度为25℃;p H 5～7时菌丝生长加快,pH 7时最适于菌丝生长;以蔗糖为碳源、硫酸铵为氮源时菌丝生长最好。不同高山杜鹃品种对小新壳梭孢的抗性存在差异,18个品种中免疫品种2个,高抗品种2个,抗病品种3个,中感品种3个,感病品种4个,高感品种4个。
文摘Unusually high levels of dieback have recently been reported in sugar maple, Acer saccharum Marsh., in Upper Michigan, and a network of plots was established to determine the extent and factors associated with the dieback. A possible contributor to this dieback is sapstreak disease caused by Ceratocystis virescens (Davidson) Moreau. Unhealthy trees with considerable crown dieback were evaluated across the western Upper Peninsula, MI to determine the prevalence of the sapstreak fungus using a minimally destructive sampling technique. Approximately 8% of 90 trees sampled were sapstreak positive and approximately 10% of trees were positive at one site that had recently been harvested. While the high levels of maple dieback present in these forests appear not to be directly caused by widespread sapstreak disease, the occurrence of sapstreak may be significantly impacting trees at some locations. However, even when present on a low number of trees, the biointeraction of sapstreak and decay rates from other fungi could be important for future tree mortality and value to the forest industry. Therefore, the effect of two sapstreak fungal isolates on the amount of decay caused by two common maple white rot fungi, Trametes versicolor (L.:Fr.) Pilat. And Irpex lacteus (Fr.:Fr.) Fr. was tested in the laboratory. Sugar maple wood blocks were precolonized by two native isolates of C. virescens followed by inoculation and incubation with decay fungi. Mean percent weight loss of blocks by white rot decay fungi ranged from 39% to 55%, but decay rates were not significantly affected by the presence of the sapstreak fungus.
文摘Today,shisham plantations in Punjab,Pakistan face major constraints,especially dieback disease.This article reviews the multidisciplinary team work by forest and plant pathologists and economists to resolve the confusions in the pathology of dieback disease.It is intended to be of practical use to the foresters and plant pathologists reporting on this issue.
文摘In vitro Kirby-Bauer disc-diffusion assays coupled with bio-imaging software techniques were used to assess native forest dwelling “fairy ring” forming fungi (Clitocybe nebularis) and co-habitant forest tree-root colonising non pathogenic, antibiotic producing bacteria (Bacillus licheniformis, Bacillus pumilis) for their antagonism towards Japanese larch dieback oomycetes phytopathogens which also affects ornamental alternative hosts. The aqueous extracts of C. nebularis exhibited the highest clearance (inhibitory) zone of 21.4 × 105 pixels = 573%) against Phytophthora ramorum than growth/clear zone Cartesian integrates recorded in untreated (control) disc (3.7 × 105 pixels = 100%) over 3-day incubation. The fairy ring fungal extracts also exhibited substantive antagonism against P. kernoviae (147%), P. lateralis (347%) and a solanaceous crop infecting P. infestans (86%). Quite encouragingly, the soil oomycete phytopathogen P. ramorum was inhibited strongly (mean ~ 177%) by both forest bacilli. Aqueous extracts of non-forest antifungal herbaceous plants (garlic and elderberry) expressed similar inhibitory effects (mean ~ 70%). A seaweed fungal elicitor component fucoidan showed moderate levels (mean ~ 85%) of antagonism against P. ramorum, P. kernoviae, P. lateralis and P. infestans. The results in this in vitro study highlight the intensity and vigor of antagonistic forest microflora and non-forest herbaceous antifungal agents such as garlic and other plant extracts as serious candidates for suppression of the oomycete Phytophthora pathogenic fungi in forest soils. This study calls for urgent scoping and impact assessment studies in pot experiments and mini-plot forest trials to gauge the fitness of these natural resources for field level potential biotechnological applications to combat the devastating dieback disease in the native woodlands and horticulture.
