Control of verticillium wilt in Cotinus coggygria

We analyzed the inhibition rates of eight kinds of fungicides to the pathogen of verticillium wilt of smoke tree (Cotinus coggygria) by measuring mycelium growth. Results show that four fungicides (Weijunjing, thiophanate-methyl 70% WP (wettable powder), carbendazim 50% WP and Junxianwei) have the best antifungal effects. Three fungicides, Weijunjing, carbendazim 50% WP and Junxianwei, were selected to determine the control of verticillium wilt in potted smoke tree seedlings. We found that the relative efficacy of Weijunjing was up to 74%. Based on the results, Weijunjing and carbendazim 50% WP were prepared for field trials. The results indicate that the relative efficacy of Weijunjing (300 times diluted) and carbendazim 50% WP (400 times diluted) were 66.2% and 48.9% in plot 1 and 26.4% and 31.8% in plot 2 after soil disinfection, and were 224% and 61.8% in plot 3 without soil disinfection in 2007. The relative efficacy of Weijunjing and carbendazim 50% WP were 49.6% and 45.4% in plot 2 in 2008.     

Electrophoretic protein profiles of strains of Ceratocystis fimbriata f. sp. platani

Soluble proteins extracted from the mycelium of strains of Ceratocystis fimbriata (Ell. et Halst) Davidson f. sp. platani Walter were separated on native and SDS-polyacrylamide gradient gel electrophoresis. The protein patterns were compared and the electrophoretic profiles of all the strains examined showed striking intraspecific similarities. The use or protein banding patterns as a diagnostic criterion to distinguish strains of C. fimbriata is discussed.     

Control of verticillium wilt in Cotinus coggygria

We analyzed the inhibition rates of eight kinds of fungicides to the pathogen of verticillium wilt of smoke tree(Cotinus coggygria) by measuring mycelium growth.Results show that four fungicides(Weijunjing,thiophanate-methyl 70% WP(wettable powder),carbendazim 50% WP and Junxianwei) have the best antifungal effects.Three fungicides,Weijunjing,carbendazim 50% WP and Junxianwei,were selected to determine the control of verticillium wilt in potted smoke tree seedlings.We found that the relative efficacy of Wei...     

杀菌剂对合欢枯萎病菌的毒力测定

采用抑菌圈法和生长速率法对合欢枯萎病菌进行杀菌剂毒力测定的结果表明：多菌灵、根府咛、硫磺·多菌灵、福美双、代森锰锌等杀菌剂对合欢枯萎病菌有明显的抑菌效果;多菌灵、根府咛、硫磺·多菌灵的抑菌效果较好,可望应用于合欢枯萎病的大田防治试验。     

Evaluation of fungicides for the control of Botryosphaeria corticola on cork oak in Catalonia (NE Spain)

Botryosphaeria canker of cork oak (Quercus suber L.), caused by Botryosphaeria corticola, is a well-known factor contributing to the decline of this forest species and is a serious disease in the main cork-producing countries of the Western Mediterranean basin. In this work, fungicides with the potential for controlling the disease were selected using a combination of in vitro tests and field trials. Fourteen fungicides in different chemical families were tested in vitro to evaluate their effect on inhibition of mycelial growth. The most effective fungicides were benomyl, carbendazim, cyprodinil + fludioxonil, thiabendazol and thiophanate-methyl; these compounds were then further tested under field conditions. In the field trials, carbendazim and thiophanate-methyl were the most effective fungicides, as shown by efficacy indices, in reducing debarked trunk surface affected by cankers (76% and 50–65%, respectively). These results suggest that the occurrence of Botryosphaeria canker on cork oak can be reduced effectively with the application of selected fungicides after cork removal from the trees.     

In vitro evaluation of fungicides against Cylindrocladium spp. causing diseases of Eucalyptus in Kerala,India1

A total of 22 fungicides were evaluated in vitro for their efficacy against Cylindrocladium quinqueseptatum (CQ), C. ilicicola (CI), C. floridanum (CF), C. parvum (CP), and C. camelliae (CC) causing various diseases of Eucalyptus in Kerala, India. Though there were a number of fungicides effective (ED₁₀₀) in the comdial germination and poisoned food techniques, only carbendazim provided complete inhibition of CQ, CI and CC in the soil-fungicide screening technique; carbendazim was also highly effective against CF and CP. C. ilicicola appeared to be more tolerant than other species of Cylindrocladium as only a few fungicides were found to be effective against it even in the conidial germination technique. On comparison of the three fungicidal evaluation techniques, it is concluded that, for a pathogen producing microsclerotia, like Cylindrocladium, the soil-fungicide screening technique is the most appropriate one for obtaining reliable results.     

Untersuchungen zur Biologie,Morphologie und Verbreitung von Herpotrichia parasitica (Hartig) E. Rostrup (vormals Trichosphaeria parasitica Hartig)

Studies on the biology, morphology and spread of Herpotrichia parasitica (Hartig) E. Rostrup (formerly Trichosphaeria parasitica Hartig). Part II: Method of infection, hosts and pure culture. H. parasitica (Hartig) E. Rostrup (conidial stage Pyrenocbacta parasitica Preyer et van der Aa) overwinters by means of both types of fruit bodies on the needles of hosts but also by means of mycelium which grows along the under sides of shoots during the growing season, reaches the buds and penetrates under the outer bud scales. Spread of the fungus is thus independent of spores. As well as Abies alba, other silver firs are attacked. Contact infection with mycelium on Picea sitchensis was also observed. Studies with pycnospores showed that germination on needles of host species varied with humidity. In culture the fungus grew best on 2 % malt agar, pH 6 at 21°C.     

化学药剂防治杉木种子园球果病害的室内药效试验

应用 10种化学药剂防治杉木种子园的 2种主要球果病害的室内药效试验结果表明 :内吸杀菌剂多菌灵、甲基硫菌灵对病原菌的菌丝生长、孢子萌发有强毒杀抑制作用     

Effects of some bacteria (Pseudomonas spp. and Erwinia herbicola) on in vitro growth of Piptoporus betulinus

Summary Bacteria including Pseudomonas putida, Pseudomonas fluorescens biovar I, Pseudomonas fluorescens biovar V, Pseudomonas aureofaciens and Erwinia herbicola were isolated from discoloured zones in birch trunks. Antagonistic effects of these bacteria to growth of Piptoporus betulinus mycelium were tested in vitro, both in dual culture and using bacterial cell‐free culture filtrates. In dual cultures, P. putida was most effective at inhibiting mycelial growth of Piptoporus betulinus. Filtrates of P. putida inhibited growth of P. betulinus mycelium irrespective of filtrate concentration, incubation time of bacteria and timing of recording mycelium growth. The strongest antagonistic effect (inhibition of fungal growth) was observed on a medium containing 80% of sterile filtrate obtained from 15‐day‐old bacterial cultures. The highest stimulating effect on mycelium growth was noted on medium containing 80% filtrate obtained from 7‐day‐old E. herbicola cultures.     

In vitro influence of phosphite on chlamydospore production and viability of Phytophthora cinnamomi

Chlamydospores of four isolates of Phytophthora cinnamomi were produced on mycelium grown on medium with or without 100 μg phosphite/ml, then tested for germination on medium containing no phosphite or 100 or 160 μg phosphite/ml. For each isolate when spores were produced on medium without phosphite, there was no effect of phosphite on germination. However, chlamydospores produced in the presence of 100 μg phosphite/ml showed significantly lower germination on media with no phosphite, 100 or 160 μg phosphite/ml than those produced in the absence of phosphite. For isolates known to be phosphite sensitive, the level of viable non‐germinated chlamydospores was higher amongst those produced on medium containing phosphite than amongst the controls, suggesting phosphite induces chlamydospore dormancy in some isolates of P. cinnamomi. Chlamydospores were produced uniformly across the radius of colonies on solid or liquid control media, but on media containing 100 μg phosphite/ml, chlamydospore production was lower in the centre of the colony and peaked at a point where mycelial morphology changed from tightly packed to sparse. This change in mycelial morphology and the peak in chlamydospore numbers did not occur when the pathogen was grown on liquid medium renewed every few days. In renewed medium, chlamydospores were evenly distributed across the radius of the colony.     

澳大利亚ECM菌在尾叶桉上的筛选及其接种效应

报道４３种澳大利亚及２种国产外生菌根菌株在广东尾叶桉人工林上的筛选试验的初期研究结果。分别对试验林６、１２和２４个月的生长情况进行了调查,数据分析结果表明,与未接种对照林木相比,接种试验林在树高和地径（或胸径）生长量上均表现出显著的接种优势（Ｐ〈０．０１）;接种林３次调查平均树高生长量最大增幅分别为２６．１％、３３．７％和２７．４％,地径（或胸径）最大增幅分别为１９．２％、２１．５９％和１９．３２％;２４个月时每公顷材积最大幅为５６．８％。Ｅ０７１０（Ｌａｃｃａｒｉａ）、Ｈ４６７０（Ｌａｂｙｒｉｎｔｈｏｍｙｃｅｓ）、Ｅ４５０１（Ａｍａｎｉｔａ）、Ｅ２０１３（Ｌａｃｃａｒｉａ）、Ｃ９３０１（Ｐｉｓｏｌｉｔｈｕｓ）、Ｈ１２７２（Ｓｃｌｅｒｏｄｅｒｍａ）、Ｈ１１９４（Ｔｈａｘｔｅｒｏｇａｓｔｅｒ）、Ｈ０６０３（Ｓｃｌ     

巧家五针松育苗阶段病害及防治方法

调查了巧家五针松育苗阶段的病害类型、症状、病原和危害,采用在育苗中圃地选择、土壤消毒、药剂浸种、播种时间和苗期药物治疗5种方法进行防治试验。结果表明:苗期主要病害有种芽腐烂、茎叶腐烂、幼苗猝倒、苗木立枯、苗木枯梢。在圃地育苗,生荒地发病率比熟地减少17%;在3月中旬播种、播种前药剂消毒土壤和浸种降低发病率;苗期喷50%多菌灵wp 1 000 mg/kg防治效果达78%,好于托布津、百菌清和波尔多液。     

Effect of fungicides,endophytes and fungal filtrates on in vitro growth of Spanish isolates of Gremmeniella abietina

The effect of eight fungicides and 15 endophytes isolated from twigs of healthy Pinus halepensis trees on the growth rate of four Spanish isolates of the pathogen Gremmeniella abietina was evaluated in vitro. In the fungicide experiments, four doses of each fungicide tested were added to the growth medium. In the endophyte experiments, dual cultures endophyte‐pathogen were paired in Petri dishes. Furthermore, growth of three G. abietina isolates was evaluated on malt agar with pine needle extract amended with filtrates from cultures of endophyte E14, which produced a brownish compound apparently inhibiting G. abietina growth. The results obtained suggested that chlorothalonil and daconil were the most suitable fungicides at low doses to reduce growth of G. abietina isolates from Spain. Four of the endophytes tested in vitro showed strong antagonistic activity against G. abietina and deserve further testing in vivo. The endophyte E14 produced in vitro a brownish compound which almost completely inhibited mycelial growth of G. abietina isolates from Spain.     

The influence of time,soil moisture and exogenous factors on the survival potential of oospores and chlamydospores of Phytophthora cinnamomi

The mode of persistence of Phytophthora cinnamomi, a highly aggressive soil‐ and water‐borne pathogen, remains unclear. This study investigated the survival of viable oospores and chlamydospores of P. cinnamomi when present as free propagules in untreated soil, or in soil subject to four exogenous treatments: smoke water, fish emulsion and two fungicides (ridomil and furalaxyl). The exogenous treatments were applied under moist and dry soil conditions. Spore viability was determined by the thiazolyl blue tetrazolium bromide (MTT) staining technique, with a qPCR assay used to compare general patterns of decline. Over 96% of oospores lost viability over a period of 48 weeks irrespective of soil moisture conditions. The mean percentage viability for oospores decreased from 91% at time zero to 72, 35, 20 and 1% after 6, 12, 24 and 48 weeks, respectively. Reduction in viability of chlamydospores was more rapid than oospores, with viability declining from 92% to zero after 12 weeks. There was no significant difference between untreated soil and the exogenous treatments. The RNA‐based qPCR assay indicated a strong presence of viable oospores of P. cinnamomi up to week 12 for moist soil and week 3 for dry soil, but thereafter failed to detect RNA even though viable oospores could be detected by MTT staining. Based on the MTT staining, this study indicated that viability of P. cinnamomi oospores may be entirely lost within 1 year and that of chlamydospores within 3 months for the soil type tested. Therefore, oospores and chlamydospores when existing as free propagules in soil appear unlikely to be involved in the long‐term survival of P. cinnamomi.     

Efficacy of fungicides on Hymenoscyphus fraxineus and their potential for control of ash dieback in forest nurseries

Twenty‐six commercial formulations of fungicides at six concentrations were evaluated in vitro for their efficacy on mycelial growth of Hymenoscyphus fraxineus (anamorph Chalara fraxinea). The results are presented as EC₅₀, EC₉₀ and minimal inhibitory concentration values; the comparisons with the recommended application concentrations showed that 10 of the 26 fungicides were highly effective in their ability to inhibit the mycelial growth of the pathogen. The eight most effective fungicides identified based on multiple comparisons analysis were azoxystrobin, bitertanol, captan (in two‐component preparation with trifloxystrobin), difenoconazole, kresoxim‐methyl, spiroxamine (in multicomponent preparation with tebuconazole and triadimenol), tebuconazole and trifloxystrobin. Azoxystrobin, difenoconazole, kresoxim‐methyl, mancozeb, myclobutanil, pyrimethanil, tebuconazole and trifloxystrobin were selected to verify their effectiveness in in planta tests. During two field tests in nurseries, it was found out that tebuconazole (triazole), trifloxystrobin and kresoxim‐methyl (strobilurins) and mancozeb (dithiocarbamate) were significantly effective against H. fraxineus. The best results were gained with tebuconazole, when mean percentage of diseased saplings was 16.3%, whereas in the control, it was 63.6%. The combination and alternation of fungicides from the triazole, strobilurine and dithiocarbamate chemical groups should be an effective tool for protecting ash saplings in forest nurseries. Moreover, exact timing of the treatment reflecting rainfall and development of first symptoms in the foliage will be also important.     

A propos de Grovesiella abieticola (Zell. et Goodd.) Morelet et Gremmen

On Grovesiella abieticola (Zell. and Goodd.) Morelet and Gremmen . Grovesiella abieticola (=Scleroderris abieticola) is an inoperculate Discomycete (related but distinct from the genera Godronia Moug. et Lév., Durandiella Seaver and Pragmopora Massal.), occurring in Europe and North America on species of the genus Abies Miller. The fungus is associated with branch cankers and dieback of twigs, although its pathogenicity has not been proved so far. After a three-weeks period of growth in vitro the fungus develops plurilocular pycnidia oozing bacilliform, unicellular microconidia. It demonstrates an optimal growth at 18–20°C.     

银杉落针病的初步研究

由散斑壳菌Lophoder mium sp.引起的落针病是银杉的一种重要叶部病害,导致针叶大量提早脱落,影响树木生长甚至濒于死亡。百菌清、多菌灵、甲基托布津等杀菌剂对病原菌子囊孢子萌发的抑制作用较强,以营林为主、药剂防治为辅的防治方法能控制该病的发生与流行。     

Phytoalexin production by Aspen (Populus tremuloides Michx.) in response to infection by Hypoxylon mammatum (Wahl.) Mill and Alternaria spp.

Freshly wounded stem sections of P. tremuloides Michx. produce phytoalexin when inoculated with mycelium of Hypoxylon mammatum (Wahl.) Mill., and Alternaria sp. These exudates are inhibitory against spore germination of these two fungi and, although inhibitory against mycelial growth of Alternaria sp., have no effect on the mycelial growth of H. mammatum. It was possible to correlate the amount of phytoalexin elicited by different strains with the inhibitory activity.     

Growth and behaviour of Ceratocystis fimbriata in Plane-tree tissues A scanning electron microscope study

Ceratocystis fimbriata(Ell. et Halst.) Davidson f. platani Walter development in Plane-tree (Platanus Orientalis L.) tissues was examined by scanning electron microscope. All the fungal elements are smooth except for doliform endoconidia which are characterized by a rough surface and protruding rims. The fungus penetrates lesions and spreads rapidly along medullary rays into the pith and finally into the xylem elements. The hyphal presence in pith cells causes the disappearance of plastids and breakdown of the middle lamellae. The internal walls of vessels are not affected by hyphal activity during the period of the study.     

L'effet d'acides gras sur la stimulation des périthèces de Ceratocystis ips,C. minor et C. capillifera

The effect of fatty acids in stimulating production of perithecia of Ceratocystis ips, C. minor and C. capillifera. Perithecia formation of three species of Ceratocystis is stimulated by somo unsaturated fatty acids, spccially linoleic acid, and one saturated fatty acid (arachidic acid).