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1.
Inoculating plant material by jet injection 总被引：1，自引：1，他引：0
R. L. WASTIE 《Plant pathology》1984,33(1):61-63
Both tubers and plants of potato were successfully inoculated with Erwinia carotovora subsp. itroseptica by means of a needle-less medical jet injector. The instrument has also been used to infect potato tubers with Phorna exigua var. foveata, Fusarium solani var. coeruleum and F. sulphureum. It is suggested that high-pressure injection is a potentially useful tool for introducing pathogens into plant materials. 相似文献
2.
Increases in resistance to Fusarium sulphureum and Fusartium solani var. coeruleum were determined in seed tubers of cultivars Desiree, Pentland Hawk and Kerr's Pink with light-enhanced glycoalkaloids. Glycoalkaloid concentration in the tubers ranged from 78.0 to 885.9 mg kg−1 fresh weight. Exposure of tubers to light prior to inoculation decreased fungal invasion, the greater reductions generally reflecting longer light exposure periods. In most cases, no direct relationship between resistance and glycoalkaloid concentrations was recorded for F . sulphureum. Surface infection indices and reduced depth of rot caused by F. solani var. coeruleum were closely correlated with tuber glycoalkaloid content. No significant effects on spore length and width were recorded. Exposure to light of seed tubers that are not destined for human or animal consumption could provide a pretreatment to reduce fungal invasion by F. sulphureum and F. solani var. coeruleum . 相似文献
3.
Botryodiplodia theobromae causes a spreading rot of sweet potato, while Botrytis cinerea, Phoma exigua var. foveata and Fusarium solani var. coeruleum cause rots of limited extent. Cladosporium cucumerinum does not rot sweet potato tuber tissue. Whichever of these fungi is inoculated into tubers, a zone at the margin of the lesion can be clearly distinguished, from slightly affected but uninfected tissue on one side and infected rotted tissue on the other, by its high content of phenolic substances and polyphenol oxidase and peroxidase activities. Polygalacturonase is present in this zone for spreading B. theobromae lesions but not for the limited lesions caused by the other fungi. Total content of phenolic substances is generally greater in and around limited lesions. 相似文献
4.
The effectiveness of various methods for detecting three fungal potato pathogens was compared with artificially infested soil, naturally infested tuber-borne soil and field soil. In the spring of 1985 and 1986 field soils from 30 farms in north-east Scotland were sampled just before planting a seed potato crop and 6 months after harvesting such a crop. The minimum statutory gap between crops is 5 years. Polyscytalum pustulans was recovered from 32 out of 60 field soil samples taken 6 months after harvest while from fields sampled in the spring before a potato crop was planted the fungus was isolated from 10 out of 30 soils in 1985 and five out of 30 in 1986. Phoma foveata was isolated from only one out of 60 pre-planting soil samples but Fusarium solani var. coeruleum was recovered from eight of these soils.
Microplant bait plants were grown over 3 years at an experimental farm near Edinburgh in various fields at different intervals after a previous potato crop. Contamination by P . pustulans was not related to interval after potatoes between 1 - 7 years. No contamination was recorded in fields where potatoes had not been grown for more than 30 years. 相似文献
Microplant bait plants were grown over 3 years at an experimental farm near Edinburgh in various fields at different intervals after a previous potato crop. Contamination by P . pustulans was not related to interval after potatoes between 1 - 7 years. No contamination was recorded in fields where potatoes had not been grown for more than 30 years. 相似文献
5.
Between 1988 and 1991, isolates of Polyscytalum pustulans were obtained from potato tubers grown in Scotland and tested for sensitivity to thiabendazole (TBZ) on agar. Sensitive isolates did not grow at 1 mg TBZ/1, whereas growth of resistant isolates was unaffected at 1 mg and reduced by 10–30% at 10 mg/1. Resistant isolates were present on all classes of seed potatoes, and were also recovered from the air of stores during grading. Isolates from a stock of seed tubers from Northern Ireland were resistant. All 44 isolates of Fusarium solani var. coeruleum collected in 1991 were sensitive to TBZ. 相似文献
6.
D. L. EBBELS 《Plant pathology》1983,32(2):145-150
Seed potato tuber inspections were inaugurated in England and Wales as a training exercise daring 1974–77, preparatory to the operation of seed potato classification under statutory authority as from 1978. The number of stocks inspected varied from 359 for the 1976 harvest (38% of those classified) to 536 for the 1975 harvest (52%). The proportion of stocks meeting the required standards progressively increased from 82% for 1974 crops to 91% for 1977 crops. The diseases most commonly causing the failure of stocks to meet the required standards were gangrene ( Phoma exigua var. foveata ) for crops harvested in 1974, 1975 and 1977, and non-bacterial soft rots for 1976 crops. Over the 4 years the proportion of stocks failing to meet the required standards for diseases were respectively: 1.2% for tuber blight ( Phytophthora infestans ); 0.6% for bacterial soft rots ( Erwinia carotovora subspp.); 2.0% for non-bacterial soft rots (including Phytophthora erythroseptica and Pythium ultimum ); 0.8% for dry rots ( Fusarium spp.); 4.0% for gangrene; 0.1% for skinspot ( Polyscytalum pustulans ); 0.1% for black scurf ( Rhizoctonia solani ); 0.1% for powdery scab ( Spongospora subterranea ) and 1.6% for common scab ( Streptomyces spp.). 相似文献
7.
Contamination of stem-cutting bait plants exposed at various locations in and around a potato crop was greatest within the crop, less outside it and least at a site c. 20 km from commercial crops. Within the crop about half the stem infection and tuber contamination detected had occurred before haulm destruction. The incidence of contamination on tubers of bait plants placed within the crop was similar to that on tubers from the surrounding plants. Phoma exigua var. foveata was recovered from green leaves sampled at intervals between June and early September. In one year contamination by P. exigua var. foveata of tubers sampled from healthy plants surrounding a diseased plot was greatest in samples adjacent to the plot and decreased progressively away from it. This pattern was less apparent in two other years. These results are discussed in relation to the spread of airborne inoculum. 相似文献
8.
The incidence of potato pathogens on healthy roots of micropropagated (MP) and seed tuber (ST) plants was examined on successive dates during the growing season in two field experiments. Microplants were grown in a glasshouse for 4–5 weeks in perlite or peal-based substrates, and exposed or not to natural inoculum before planting in the field. The seed tubers originated from stocks of visually clean or moderately blemished tubers and were surface-sterilized or not before planting. Polyscytalum pustulans and Helminthosporium solani only infected roots of ST plants and inoculated MP plants. The incidence of P. pustulans was affected by seed tuber-borne inoculum and, in I year, by the substrate. H. solani was detected infrequently on roots. Rhizoctonia solani was present at low frequencies in most root samples, and more ST than MP plant roots were colonized; there were no substrate effects. In 1 year, increased inoculum levels increased root infection, but only in MP roots. Colletotrichum coccodes occurred at high frequencies and was most common in roots of ST plants. Progeny tubers showed some treatment effects when tested in September and after storage for 6 months, but there were no consistent relationships between root and progeny tuber infection. 相似文献
9.
Fusarium species obtained from stored potato tubers affected with dry rot were grown on agar containing thiabendazole. All 40 isolates of F. coeruleum and 60 isolates of F. avenaceum tested were sensitive to the fungicide, but 68% of the 85 isolates of F. sulphureum and one isolate of F. culmorum were classified as resistant. When isolates were made from dry rots on tubers that had been treated with thiabendazole during loading into store, all 81 isolates of F. sulphureum were resistant, whereas all the isolates of F. coeruleum (25), F. avenaceum (4) and Phoma foveata (10) were sensitive. Resistance was not found in five isolates of Cylindrocarpon destructans. All the Fusarium spp. were sensitive to imazalil and were pathogenic when inoculated into potato tubers. Resistant and sensitive isolates of F. sulphureum caused rots of similar size. 相似文献
10.
Tubers infected with thiabendazole-sensitive isolates of Polyscytalum pustulans and Helminthosporium solani were treated annually for 4 years with benomyl, thiabendazole or a formulated mixture of thiabendazole and imazalil, and grown at three farms in Scotland. The proportion of thiabendazole-resistant isolates of H. solani increased, and isolates producing black colonies became more common with successive annual applications of thiabendazole or benomyl. Silver scurf was not reduced after three annual applications. When these fungicides were applied once to untreated seed the incidence of resistant isolates of H. solani was much less in 1988 than in 1991 when tubers had been grown on farms for 3 years from untreated seed.
The proportion of resistant isolates of P. pustulans increased with the number of successive applications of thiabendazole or benomyl but at differing rates on each farm. At one farm, skin spot was not reduced by three annual applications of these fungicides whereas at the other farms it was reduced by 90–100% by four annual applications.
A smaller proportion of resistant isolates of P. pustulans and H. solani was obtained after applying the mixture of thiabendazole and imazalil than after benomyl or thiabendazole alone. Their occurrence was not related to the number of fungicide applications. The mixture also reduced both diseases by more than 75% over the 4 years.
At one farm where resistant isolates of H. solani were present, tubers were infected when stored on trays but not when stored in bags. 相似文献
The proportion of resistant isolates of P. pustulans increased with the number of successive applications of thiabendazole or benomyl but at differing rates on each farm. At one farm, skin spot was not reduced by three annual applications of these fungicides whereas at the other farms it was reduced by 90–100% by four annual applications.
A smaller proportion of resistant isolates of P. pustulans and H. solani was obtained after applying the mixture of thiabendazole and imazalil than after benomyl or thiabendazole alone. Their occurrence was not related to the number of fungicide applications. The mixture also reduced both diseases by more than 75% over the 4 years.
At one farm where resistant isolates of H. solani were present, tubers were infected when stored on trays but not when stored in bags. 相似文献
11.
G. J. JELLIS 《Plant pathology》1982,31(2):171-177
Disease incidence was recorded in tubers of various cultivars following inoculation with macerated mycelium of Phoma exigua var. foveata and wounding in various ways. A method which produced predominantly crush wounds gave most rots and the most consistent results. The length of time between inoculation and wounding did not significantly affect the incidence of disease but disease severity did increase with damage infliction time. Inoculated, undamaged tubers produced rots but the incidence was low and discrimination between cultivars was poor when compared with damaged tubers. In some tests the resistance to gangrene could be measured by the proportion of tubers affected, in others all tubers had lesions but the extent of infection was different, The latent period of the disease differed between cultivars. Rate of lesion development was constant over a period of 12 wk within cultivars but differed between them. 相似文献
12.
ABSTRACT Specific and sensitive quantitative diagnostics, based on real-time (TaqMan) polymerase chain reaction (PCR) and PCR enzyme-linked immunosorbent assay, were developed to detect dry-rot-causing Fusarium spp. (F. avenaceum, F. coeruleum, F. culmorum, and F. sulphureum). Each assay detected Fusarium spp. on potato seed stocks with equal efficiency. Four potato stocks, sampled over two seed generations from Scottish stores, were contaminated with F. avenaceum, F. sulphureum, F. culmorum, F. coeruleum or a combination of species, and there was a general trend towards increased Fusarium spp. contamination in the second generation of seed sampled. F. sulphureum and F. coeruleum caused significantly (P < 0.05) more disease in storage than the other species when disease-free tubers of potato cvs. Spunta and Morene were inoculated at a range of inoculum concentrations (0, 10(4), 10(5), and 10(6) conidia/ml). Increased DNA levels were correlated with increased disease severity between 8 and 12 weeks of storage. The threshold inoculum levels resulting in significant disease development on both cultivars were estimated to be 10(4) conidia/ml for F. sulphureum and 10(5) conidia/ml for F. coeruleum. To study the effect of soil infestation and harvest date on disease incidence, seed tubers of cvs. Morene and Spunta were planted in a field plot artificially infested with the four Fusarium spp. F. culmorum and F. sulphureum were detected in soil taken from these plots at harvest, and F. sulphureum DNA levels increased significantly (P < 0.05) at the final harvest. All four Fusarium spp. were detected in progeny tubers. There was a trend toward higher levels of F. culmorum detected in progeny tubers at the earliest harvest date, and higher levels of F. sulphureum at the final harvest. The use of diagnostic assays to detect fungal storage rot pathogens and implications for disease control strategies are discussed. 相似文献
13.
黑龙江省马铃薯干腐病菌种类鉴定及致病性 总被引：5，自引：0，他引：5
本研究将采自黑龙江省不同地区的马铃薯干腐病病样进行分离和病原菌纯化,得到27个镰刀菌菌株,通过致病性鉴定,其中的18个菌株具有致病性。运用培养性状和形态特征综合分析的方法,对上述18个菌株进行鉴定,结果显示为6种镰刀菌,分别为拟枝孢镰孢(Fusarium sporotrioides)、茄镰孢(F.solani)、接骨木镰孢(F.sam-bucinum)、拟丝孢镰孢(F.trichothecioides)、燕麦镰孢(F.avenaceum)和茄病镰孢蓝色变种(F.solanivar.coerule-um)。同时对上述6种镰刀菌进行致病性测定,结果表明不同种类镰刀菌致病性不同,以接骨木镰孢、燕麦镰孢和拟丝孢镰孢致病力最强,拟枝孢镰孢致病力最弱。 相似文献
14.
J. C. Peters † A. K. Lees D. W. Cullen L. Sullivan G. P. Stroud A. C. Cunnington 《Plant pathology》2008,57(2):262-271
A 3-year survey was undertaken to establish the relative frequency of different Fusarium spp. present as inoculum on potato tubers collected from four regions of Great Britain. A total of 219 samples (comprising 10 950 tubers) were collected from the 2000, 2001 and 2002 crops and processed to recover dry rot-producing isolates. In total, 228 isolates of Fusarium spp. were recovered. Most (94·7%) of these isolates were attributed to one of four Fusarium species: F. coeruleum, F. avenaceum, F. culmorum and F. sambucinum (formerly F. sulphureum) . The incidence of the combined Fusarium spp. increased the further south the crops had been grown. Fusarium coeruleum was the most commonly isolated species in each survey year, comprising 37 to 52% of the total Fusarium species. Selected isolates of each species were evaluated for their ability to produce rots in potato tubers. Fusarium sambucinum was a more aggressive pathogen than the other Fusarium species in eight out of 10 cultivars. Fusarium avenaceum and F. culmorum were relatively weaker pathogens. However, these species were aggressive on some cultivars, notably Hermes. The selected isolates were also assessed for their sensitivity to the fungicides thiabendazole and imazalil. Using in vitro tests, 65% of F. sambucinum isolates were resistant to thiabendazole and 7% of F. avenaceum isolates were resistant to imazalil. Tubers treated with imazalil yielded a higher proportion of isolates of F. avenaceum than those that were untreated. Similarly, a higher proportion of F. sambucinum isolates were recovered from tubers treated with thiabendazole than from those that were not treated. 相似文献
15.
The effect of humidity on potato gangrene development in naturally contaminated tubers 总被引：2，自引：2，他引：0
During the winters of 1977/78 and 1978/79 tubers of cv. Arran Banner naturally contaminated with Phoma exigua var, foveata were kept at either high or low humidity and at 5, 10, 15 or 20 C. During the 1978/79 winter cv. Majestic tubers were stored under similar conditions at 5 and 10°C only. At monthly intervals tubers from each lot were damaged to encourage gangrene development and returned to their storage condition except the Majestic tubers which were switched from high to low humidity or vice versa and returned to the appropriate temperature. No gangrene rots developed in tubers kept at 1 5 or 20°C at either humidity. At 5 and 10°C fewer rots developed at high humidity compared with low humidity including Majestic tubers kept Initially at high humidity. Inoculum levels in soil on tubers were not markedly affected by storage conditions. 相似文献
16.
Infestation of ridge soil by Phoma foveata was examined over 4 years by collecting soil samples at various distances from seed tubers which were either naturally infected or inoculated with a distinctive strain. Samples were taken on four occasions during each growing season. Infestation was greatest immediately around the tuber and was largely confined to a distance of 15 cm until haulm destruction, after which P. foveata was detected more widely in the soil.
The effects of various seed-tuber and haulm treatments on the incidence of daughter-tuber contamination by P. foveata were assessed over 5 years. Removing the infected seed tuber at emergence significantly (P < 0.05) reduced the contamination at haulm destruction of daughter tubers harvested by hand in only 1 out of 4years. In all years, tuber contamination was much less(P < 0.05) when stems were pulled and removed than when they were desiccated by applying diquat dibromide. The incidence of tuber contamination did not increase between haulm destruction and harvest when stems were pulled and removed. In another experiment, tuber contamination increased linearly with the delay in pulling haulms after applying diquat dibromide. Cutting and removal of stems tended to reduce gangrene contamination, relative to the desiccation of stems by applying diquat dibromide, in all years where the seed tuber had been removed, but in only 2 out of 5 years where the tuber was present. 相似文献
The effects of various seed-tuber and haulm treatments on the incidence of daughter-tuber contamination by P. foveata were assessed over 5 years. Removing the infected seed tuber at emergence significantly (P < 0.05) reduced the contamination at haulm destruction of daughter tubers harvested by hand in only 1 out of 4years. In all years, tuber contamination was much less(P < 0.05) when stems were pulled and removed than when they were desiccated by applying diquat dibromide. The incidence of tuber contamination did not increase between haulm destruction and harvest when stems were pulled and removed. In another experiment, tuber contamination increased linearly with the delay in pulling haulms after applying diquat dibromide. Cutting and removal of stems tended to reduce gangrene contamination, relative to the desiccation of stems by applying diquat dibromide, in all years where the seed tuber had been removed, but in only 2 out of 5 years where the tuber was present. 相似文献
17.
B. P. J. de Lacy Costello P. Evans R. J. Ewen H. E. Gunson P. R. H. Jones N. M. Ratcliffe † P. T. N. Spencer-Phillips 《Plant pathology》2001,50(4):489-496
Volatile organic compounds (VOCs) collected from potato tubers inoculated with Phytophthora infestans (late blight), Fusarium coeruleum (dry rot) or sterilized distilled water (as a control) were analysed using gas chromatography–mass spectrometry (GC–MS) and gas chromatography–flame ionization detection (GC–FID). A total of 52 volatiles were identified by GC–MS in the headspaces above P. infestans- and F. coeruleum- inoculated tubers after incubation for 42 days in the dark at 10°C. Of these VOCs, the six most abundant were common to both pathogens. These were benzothiazole (highest abundance), 2-ethyl-1-hexanol (second highest abundance), and at approximately equal third abundance, hexanal, 2-methylpropanoic acid-2,2-dimethyl-1-(2-hydroxy-1-methylethyl)-propyl ester, 2-methylpropanoic acid-3-hydroxy-2,4,4-trimethyl-pentyl ester and phenol. In addition, styrene also occurred at approximately equal third abundance in the headspace of F. coeruleum- inoculated tubers, but at lower abundance in the headspace of P. infestans- inoculated tubers. Some VOCs were specific to each pathogen. Butanal, 3-methylbutanal, undecane and verbenone were found at low levels only in the headspace of tubers inoculated with P. infestans , while 2-pentylfuran and copaene were found only in the headspace of tubers inoculated with F. coeruleum . Additionally GC–FID analysis identified ethanol and 2-propanol in the liquid exudate from both P. infestans - and F. coeruleum -inoculated tubers after incubation for 35 days, and in the headspace after incubation for 42 days. These data provide key information for developing a sensor-based early warning system for the detection of postharvest diseases in stored potato tubers. 相似文献
18.
Effects of benzothiadiazole and acetylsalicylic acid on β-1,3-glucanase activity and disease resistance in potato 总被引：1，自引：0，他引：1
Benzothiadiazole (BTH), as Bion WG50, and acetylsalicylic acid (ASA) treatments of potato foliage of field- and glasshouse-grown potato plants were compared for control of two foliar diseases, early blight ( Alternaria solani ) and powdery mildew ( Erysiphe cichoracearum ). The effect of these treatments on harvested tubers wound-inoculated with the dry rot fungus ( Fusarium semitectum ) was also evaluated. BTH (50 mg a.i. L−1 ) gave almost complete control of both foliar pathogens on inoculated glasshouse-grown plants and reduced the severity of leaf spotting diseases (mainly early blight) in the field. BTH (100 mg a.i. L−1 ) and ASA (400 mg a.i. L−1 ) reduced the severity of dry rot in field-grown tubers in some post-harvest wound-inoculated treatments but not others and a similar reduction occurred with tubers inoculated post-harvest from BTH-treated plants grown under glasshouse conditions. BTH treatment increased β-1,3-glucanase activity in leaves > stem > tubers > stolons but not in roots. Increased enzyme activity was recorded for up to 45 days post-treatment. 相似文献
19.
麻黄根腐病病原物的分离及鉴定 总被引：7，自引：1，他引：6
2001年从宁夏麻黄基地采集麻黄根腐病病株样品10份,按照柯赫氏法则对其进行了病原物的分离、纯化、致病性测定及菌株鉴定。结果表明,发病部位分离物中主要优势菌群为镰孢属(Fusarium spp.)。分离物经致病性测定和复合接种试验发现,微胶镰孢Fusarium subglutinans致病性最强,接种后发病株率达60%以上,尖孢镰孢F. oxysporum、半裸镰孢F. semitectum、茄镰孢蓝色变种F. solani var. coeruleum和茄镰孢F. solani致病性弱,接种发病率为10%~20%,它们和微胶镰孢混合接种后的发病率均高于单独接种的发病率,其中微胶镰孢与含尖孢镰孢或半裸镰孢的组合接种发病率高于不含这2种镰孢的组合。病株上获得的其它分离物均无致病性。证实麻黄根腐病是以微胶镰孢为主要病原,并由尖孢镰孢、半裸镰孢和其它几种镰孢复合侵染导致的一种病害。 相似文献
20.
江苏省玉米茎腐病菌种类鉴定 总被引：8，自引：0，他引：8
作者于1992～1995年,从江苏省玉米主产区采集的玉米茎腐病标样中分离获得105个菌株,经鉴定,致病菌种类有肿囊腐霉(Pythium inflatum)、禾生腐霉(P.graminicola)、串珠镰孢浙江变种(Fusarium moniliforme var.zhejiangensis)、串珠镰孢中间变种(F.moniliforme var.intermedium)、串珠镰孢胶孢变种(F.moniliforme var.subglutinans)、禾谷镰孢(F.graminearum)、拟枝孢镰孢厚膜变种(F.sporotrichioides var.chlamydosporum)、尖孢镰孢芬芳变种(F.oxysporum var.redolens)、接骨木镰孢(F.sambucinum)、茄病镰孢(F.solani)、半裸镰孢(F.semitectum)等11个种或变种。其中串珠镰孢浙江变种出现频率最高,占44.8％,肿囊腐霉和禾生腐霉致病力最强,这两类菌是江苏玉米茎腐病主要病原。 相似文献