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Suthaparan A, Stensvand A, Solhaug KA, Torre S, Telfer KH, Ruud AK, Mortensen LM, Gadoury DM, Seem RC, Gislerød HR. Suppression of Cucumber Powdery Mildew by Supplemental UV-B Radiation in Greenhouses Can be Augmented or Reduced by Background Radiation Quality. Plant Dis 2014; 98:1349-1357. [PMID: 30703932 DOI: 10.1094/pdis-03-13-0222-re] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
This study demonstrates that the spectral quality of radiation sources applied with ultraviolet-B (UV-B; background radiation) affects the suppression of cucumber powdery mildew (Podosphaera xanthii) by UV-B. Suppression provided by daily UV-B exposure of 1 W/m2 for 10 min was greatest in the presence of red light or by a complete lack of background light, and powdery mildew suppression was least in the presence of ultraviolet-A (UV-A) or blue radiation compared with plants exposed only to 16 h of daily natural light supplemented with high-pressure sodium lamps that supply broad-spectrum radiation with peaks in the yellow-orange region. Exposure of powdery mildew-inoculated plants to supplemental red light without UV-B, beginning at the end of the daylight period, also reduced disease severity; however, supplemental blue light applied in the same fashion had no effect. Daily application of UV-B at 1 W/m2 beginning on the day of inoculation significantly reduced the severity of powdery mildew to 15% compared with 100% severity on control plants. Maximum suppression of powdery mildew was observed following 15 min of exposure to UV-B (1.1% severity compared with 100% severity on control plants) but exposure time had to be limited to 5 to 10 min to reduce phytotoxicity. There was no additional disease suppression when plants were exposed to UV-B beginning 2 days prior to inoculation compared with plants exposed to UV-B beginning on the day of inoculation. UV-B inhibited germination, infection, colony expansion, and sporulation of P. xanthii. The results suggest that efficacy of UV-B treatments, alone or in combination with red light, against P. xanthii can be enhanced by exposure of inoculated plants to these wavelengths of radiation during the night, thereby circumventing the counteracting effects of blue light and UV-A radiation. The effect of UV-B on powdery mildew seemed to be directly upon the pathogen, rather than induced resistance of the host. Night exposure of plants to 5 to 10 min of UV-B at 1 W/m2 and inexpensive, spectral-specific, light-emitting diodes may provide additional tools to suppress powdery mildews of diverse greenhouse crops.
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Affiliation(s)
- A Suthaparan
- Department of Plant Sciences, Norwegian University of Life Sciences, 1432 Ås, Norway
| | - A Stensvand
- Norwegian Institute for Agricultural and Environmental Research, Høgskoleveien 7, 1432 Ås, Norway
| | - K A Solhaug
- Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, 1432 Ås, Norway
| | - S Torre
- Department of Plant Sciences, Norwegian University of Life Sciences
| | - K H Telfer
- Department of Plant Sciences, Norwegian University of Life Sciences
| | - A K Ruud
- Department of Plant Sciences, Norwegian University of Life Sciences
| | - L M Mortensen
- Department of Plant Sciences, Norwegian University of Life Sciences
| | - D M Gadoury
- Department of Plant Sciences, Norwegian University of Life Sciences
| | - R C Seem
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456
| | - H R Gislerød
- Department of Plant Sciences, Norwegian University of Life Sciences
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Suthaparan A, Stensvand A, Solhaug KA, Torre S, Mortensen LM, Gadoury DM, Seem RC, Gislerød HR. Suppression of Powdery Mildew (Podosphaera pannosa) in Greenhouse Roses by Brief Exposure to Supplemental UV-B radiation. Plant Dis 2012; 96:1653-1660. [PMID: 30727454 DOI: 10.1094/pdis-01-12-0094-re] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Ultraviolet (UV)-B (280 to 315 nm) irradiance from 0.1 to 1.2 W m-2 and exposure times from 2 min to 2 h significantly suppressed powdery mildew (Podosphaera pannosa) in pot rose (Rosa × hybrida 'Toril') via reduced spore germination, infection efficiency, disease severity, and sporulation of surviving colonies. Brief daily exposure to UV-B suppressed disease severity by more than 90% compared with unexposed controls, and severity was held at low levels as long as daily brief exposures continued. Selective removal of wavelengths below 290 nm from the UV lamp sources by cellulose diacetate filters resulted in significant reduction of treatment efficacy. Exposure of plants to 2 h of UV-B during night for 1 week followed by inoculation with P. pannosa did not affect subsequent pathogen development, indicating that the treatment effect was directly upon the exposed pathogen and not operated through the host. Following 20 to 30 days of exposure, chlorophyll and flavonoid content was slightly higher in plants exposed to the highest UV-B levels. Brief daily exposure to UV-B for 5 min at 1.2 W m-2 or 1 h at 0.1 W m-2 substantially reduced mildew severity without significant phytotoxicity, and may represent a useful nonchemical option for suppression of powdery mildew in greenhouse roses and, possibly, other crops.
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Affiliation(s)
- A Suthaparan
- Department of Plant & Environmental Sciences, Norwegian University of Life Sciences, 1432 Ås, Norway
| | - A Stensvand
- Norwegian Institute for Agricultural and Environmental Research (Bioforsk), Høgskoleveien 7, 1432 Ås, Norway
| | - K A Solhaug
- Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences
| | - S Torre
- Department of Plant & Environmental Sciences, Norwegian University of Life Sciences
| | - L M Mortensen
- Department of Plant & Environmental Sciences, Norwegian University of Life Sciences
| | - D M Gadoury
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456 USA
| | - R C Seem
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456 USA
| | - H R Gislerød
- Department of Plant & Environmental Sciences, Norwegian University of Life Sciences
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Eikemo H, Gadoury DM, Spotts RA, Villalta O, Creemers P, Seem RC, Stensvand A. Evaluation of Six Models to Estimate Ascospore Maturation in Venturia pyrina. Plant Dis 2011; 95:279-284. [PMID: 30743503 DOI: 10.1094/pdis-02-10-0125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Estimates of ascospore maturity generated by models developed for Venturia pyrina in Victoria, Australia (NV and SV), Oregon, United States (OR), and Italy (IT) or for V. inaequalis in New Hampshire, United States (NH-1) or modified in Norway (NH-2) were compared with observed field ascospore release of V. pyrina from 21 site-year combinations. The models were also compared with ascospore release data from laboratory assays. In the laboratory assays, the forecasts of the NH-1 and NH-2 models provided the best fit to observed spore release. Under field conditions, the lag phases and slope coefficients of all models differed from those of observed release of ascospores. Identifying the precise time of bud break of pear to initiate degree-day accumulation was problematic at both Australian sites. This resulted in a higher deviance between bud break and first released ascospore compared with the sites in Norway and Belgium. Linear regressions of observed release against forecasted maturity generated similarly high concordance correlation coefficients. However, where differences were noted, they most often favored models that included adjustment for dry periods. The NH-2, IT, and NV models using pooled data also provided the most accurate estimates of 95% ascospore depletion, a key event in many disease management programs.
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Affiliation(s)
- H Eikemo
- Norwegian Institute for Agricultural and Environmental Research, Plant Health and Plant Protection Division, 1432 Ås, Norway
| | - D M Gadoury
- Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456
| | - R A Spotts
- Oregon State University Mid-Columbia Agricultural Research and Extension Center, Hood River 97031
| | - O Villalta
- Biosciences Research Division, Department of Primary Industries, Knoxfield, Victoria, Australia
| | - P Creemers
- Proefcentrum Fruitteelt-Applied Scientific Research, Department of Mycology, B-3800 Sint-Truiden, Belgium
| | - R C Seem
- Department of Plant Pathology, Cornell University
| | - A Stensvand
- Norwegian Institute for Agricultural and Environmental Research, Plant Health and Plant Protection Division
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Fletcher J, Bender C, Budowle B, Cobb WT, Gold SE, Ishimaru CA, Luster D, Melcher U, Murch R, Scherm H, Seem RC, Sherwood JL, Sobral BW, Tolin SA. Plant pathogen forensics: capabilities, needs, and recommendations. Microbiol Mol Biol Rev 2006; 70:450-71. [PMID: 16760310 PMCID: PMC1489535 DOI: 10.1128/mmbr.00022-05] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A biological attack on U.S. crops, rangelands, or forests could reduce yield and quality, erode consumer confidence, affect economic health and the environment, and possibly impact human nutrition and international relations. Preparedness for a crop bioterror event requires a strong national security plan that includes steps for microbial forensics and criminal attribution. However, U.S. crop producers, consultants, and agricultural scientists have traditionally focused primarily on strategies for prevention and management of diseases introduced naturally or unintentionally rather than on responding appropriately to an intentional pathogen introduction. We assess currently available information, technologies, and resources that were developed originally to ensure plant health but also could be utilized for postintroduction plant pathogen forensics. Recommendations for prioritization of efforts and resource expenditures needed to enhance our plant pathogen forensics capabilities are presented.
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Affiliation(s)
- J Fletcher
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA.
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Affiliation(s)
- R D Magarey
- Department of Plant Pathology, New York State Agricultural Experiment Station
| | - J W Travis
- Department of Plant Pathology, The Pennsylvania State University
| | | | - R C Seem
- Department of Plant Pathology, New York State Agricultural Experiment Station
| | - P A Magarey
- South Australian Research and Development Institute, Loxton, SA, Australia
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Magarey RD, Seem RC, Russo JM, Zack JW, Waight KT, Travis JW, Oudemans PV. Site-Specific Weather Information Without On-Site Sensors. Plant Dis 2001; 85:1216-1226. [PMID: 30831780 DOI: 10.1094/pdis.2001.85.12.1216] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- R D Magarey
- New York State Agricultural Experiment Station, Geneva
| | - R C Seem
- New York State Agricultural Experiment Station, Geneva
| | | | | | | | - J W Travis
- Pennsylvania State University, University Park
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Abstract
ABSTRACT Vitis labruscana 'Concord' is a grape cultivar widely grown in the United States for processing into juice and other grape products. Concord grapes are sporadically but sometimes severely damaged by the grape powdery mildew pathogen, Uncinula necator. Although the foliage is often reported to be moderately resistant to powdery mildew, severe fruit infection occurs in some years. We observed the seasonal development of powdery mildew on leaves, rachises, and berries of unsprayed Concord grapevines. Inoculations of flower and fruit clusters revealed a brief period of berry susceptibility and a protracted period of rachis susceptibility. The rachis remained highly susceptible to infection, and the severity of rachis infection increased throughout the growing season until the rachis formed a periderm shortly before harvest. In contrast, berries were nearly immune to infection within 2 weeks after fruit set. Rachis and berry infections were detected before the disease was observed on foliage, and the incidence of rachis and berry infection often exceeded disease incidence observed on foliage until after fruit acquired substantial ontogenic resistance. Excellent control of fruit infection, and adequate control of leaf infection, was achieved by two fungicide applications targeted at the peak period of fruit susceptibility. Although Concord is thought to be moderately resistant to powdery mildew, the rachis is highly susceptible, and may be the avenue by which prebloom infections make their way onto the developing fruit. Late-season infection of the rachis neither spread to the fruit, nor did it cause fruit to drop prematurely, and may be of little economic consequence on fruit destined for processing. Although fruit of V. vinifera cultivars have been reported to remain susceptible to infection until berry sugar levels reach 8 to 15%, Concord fruit become nearly immune to infection nearly 6 weeks before this stage of development. Because powdery mildew does not become conspicuous on foliage until late summer, it is generally regarded as a late-season problem on Concord grapes, and previous management programs have reflected this belief. However, the greatest contribution to control of fruit infection is due to fungicides applied during the peak period of fruit susceptibility, from bloom until shortly after fruit set, long before the disease is observed on foliage.
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Seem RC, Magarey RD, Zack JW, Russo JM. Estimating disease risk at the whole plant level with General Circulation Models. Environ Pollut 2000; 108:389-395. [PMID: 15092934 DOI: 10.1016/s0269-7491(99)00218-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/1998] [Accepted: 07/09/1999] [Indexed: 05/24/2023]
Abstract
General Circulation Models (GCMs) have been developed to assess the impacts of potential global climate change. However, these models do not provide specific weather information at the whole-plant level and thus provide only very gross estimates of conditions that affect plant and disease development. Also, climatic change may increase the frequency of extreme events that influence plant production more than changes in daily or monthly averages. One solution is a simulation approach that can scale weather information from the global down to the plant scale. Over the last 4 years, we have been developing methods to hierarchically define current and forecast weather conditions down to the whole-plant level based on nested high-resolution atmospheric (mesoscale) numerical models. Two hierarchical mesoscale model approaches were tested to downscale weather data in a vineyard. The first, known as the Localized Mesoscale Forecast System (LMFS) uses surface databases to 'localize' mesoscale output. The second, known as the Canopy-Mesoscale Forecast System (CMFS), uses a boundary layer model to downscale mesoscale output. To illustrate the utility of this approach we focused on surface wetness duration (SWD), a variable with high spatial and temporal variability. SWD is also a critical variable for prediction of plant disease. Simulations of SWD with on-site input data were compared to those derived from the mesoscale models and to on-site sensors. Forecasts of atmospheric variables by the two systems were compared to on-site observations. Success in this effort leads us to extend this method to GCMs where factors such as temperature, rainfall, relative humidity, and surface wetness can be estimated within plant and crop canopies. We explore the implications of this work on evaluating the assessment of climate change on the risk of plant disease development.
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Affiliation(s)
- R C Seem
- New York State Agricultural Experiment Station, Cornell University, Geneva, NY 14456, USA.
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Gadoury DM, Stensvand A, Seem RC. Influence of Light, Relative Humidity, and Maturity of Populations on Discharge of Ascospores of Venturia inaequalis. Phytopathology 1998; 88:902-909. [PMID: 18944867 DOI: 10.1094/phyto.1998.88.9.902] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
ABSTRACT Ascospore release in 20 populations of Venturia inaequalis was generally suppressed in wind tunnel tests during darkness and simulated rain, but the following relieved this suppression: (i) exposure to low relative humidity during simulated rain and (ii) protracted incubation of leaf samples and the consequent senescence of the pathogen population. No counterpart to (i) was observed under orchard conditions. Although V. inaequalis also released a high percentage of ascospores during darkness in field studies under simulated rain late in the season of ascospore release, this phenomenon has not been reported for natural rain events. A threshold value of 0.5 muW/cm(2) at 725 nm was identified as the minimum stimulatory light intensity. Ascospore release increased with increasing light intensity from 0.5 to 5.2 muW/cm(2) at 725 nm. There was also an intrinsic increase in ascospore release as duration of rain increased. In orchards, the combined impact of both processes is probably responsible for a delay in reaching peak ascospore release at several hours after sunrise. Ascospore release during darkness will generally constitute a small proportion of the total available supply of primary inoculum. Significant ascospore release, and therefore infection periods, can be assumed to begin shortly after sunrise, when rain begins at night in orchards with low potential ascospore dose (PAD). A PAD level of 1,000 ascospores per m(2) of orchard floor per season is suggested as a threshold, above which the night-released ascospores should not be ignored.
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Stensvand A, Gadoury DM, Amundsen T, Semb L, Seem RC. Ascospore Release and Infection of Apple Leaves by Conidia and Ascospores of Venturia inaequalis at Low Temperatures. Phytopathology 1997; 87:1046-1053. [PMID: 18945039 DOI: 10.1094/phyto.1997.87.10.1046] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
ABSTRACT Mills' infection period table describes the number of hours of continuous leaf wetness required at temperatures from 6 to 25 degrees C for infection of apple leaves by ascospores of Venturia inaequalis and reports that conidia require approximately two-thirds the duration of leaf wetness required by ascospores at any given temperature. Mills' table also provides a general guideline that more than 2 days of wetting is required for leaf infection by ascospores below 6 degrees C. Although the table is widely used, infection times shorter than those in the table have been reported in lab and field studies. In 1989 a published revision of the table eliminated a potential source of error, the delay of ascospore release until dawn when rain begins at night, and shortened the times reported by Mills for ascospore infection by 3 h at all temperatures. Data to support the infection times below 6 degrees C were lacking, however. Our objective was to quantify the effects of low temperatures on ascospore discharge, ascospore infection, and infection by conidia. In two of three experiments at 1 degrees C, the initial release of ascospores occurred after 131 and 153 min. In the third experiment at 1 degrees C, no ascospores were detected during the first 6 h. The mean time required to exceed a cumulative catch of 1% was 143 min at 2 degrees C, 67 min at 4 degrees C, 56 min at 6 degrees C, and 40 min at 8 degrees C. At 4, 6, and 8 degrees C, the mean times required to exceed a cumulative catch of 5% were 103, 84, and 53 min, respectively. Infection of potted apple trees by ascospores at 2, 4, 6, and 8 degrees C required 35, 28, 18, and 13 h, respectively; substantially shorter times than previously were reported. In parallel inoculations of potted apple trees, conidia required approximately the same periods of leaf wetness as ascospores at temperatures from 2 to 8 degrees C, rather than the shorter times reported by Mills or the longer times reported in the revision of the Mills table. We propose the following revisions to infection period tables: (i) shorter minimum infection times for ascospores and conidia at or below 8 degrees C, and (ii) because both ascospores and conidia are often present simultaneously during the season of ascospore production and the required minimum infection times appear to be similar for both spore types, the adoption of a uniform set of criteria for ascosporic and conidial infection based on times required for infection by ascospores to be applied during the period prior to the exhaustion of the ascospore supply. Further revisions of infection times for ascospores may be warranted in view of the delay of ascospore discharge and the reduction of airborne ascospore doses at temperatures at or below 2 degrees C.
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Koball DC, Wilcox WF, Seem RC. Influence of incubation-period humidity on the development of brown rot blossom blight of sour cherry. Phytopathology 1997; 87:42-49. [PMID: 18945152 DOI: 10.1094/phyto.1997.87.1.42] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
ABSTRACT When detached sour cherry (Prunus cerasus) blossoms were inoculated with conidia of Monilinia fructicola and subjected to a standard 8-h wetting treatment at 20 degrees C, blossom blight incidence was proportional to relative humidity (RH) when RH was held constant during the subsequent 6-day incubation period (frequency = 1.0 at the maximum RH of 92%; frequency = 0.38 at the minimum RH of 57%). Similarly, when a primary incubation period at 87% RH was followed by a secondary incubation period at 54% RH, blossom blight incidence was proportional to the number of hours at the higher level (frequencies of 0.94, 0.80, and 0.38 with primary incubation periods of 6 days, 36 h, and 12 h, respectively). When intact blossoms on potted trees were exposed to common inoculation and wetting treatments, disease incidence was consistently high on trees that subsequently were incubated in a controlled environment chamber (20 degrees C, 90 to 95% RH) but was extremely variable when trees were incubated under variable ambient conditions. Ambient incubation temperature had little effect on disease incidence 9 days after inoculation, whereas ambient RH had a pronounced effect: the frequency of blighted blossoms was 0.53 to 0.61 when the number of hours at RH >90% was approximately two to six times that at RH <60%, whereas this frequency was only 0.02 to 0.07 when the number of hours at RH >90% was approximately one-third the number at RH <60%. After 48 h at a constant RH of 89 or 57%, the water potential of excised uninoculated blossoms was -1.15 and -1.93 MPa, respectively; however, growth of M. fructicola on osmotically adjusted potato dextrose agar was unaffected by changes in water potential within this range. Thus, although RH during incubation has an important influence on blossom blight development, the causal mechanism remains uncertain.
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Ntahimpera N, Dillard HR, Cobb AC, Seem RC. Influence of Tillage Practices on Anthracnose Development and Distribution in Dry Bean Fields. Plant Dis 1997; 81:71-76. [PMID: 30870951 DOI: 10.1094/pdis.1997.81.1.71] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Three tillage practices-chiseling, rototilling, and moldboard plowing-were evaluated in 1993 and 1994 to determine their impact on initial disease development, distribution, and progression over time in a field of the susceptible kidney bean cultivar Horizon. The tillage treatments were administered in the spring in a field infested in 1992 with the bean anthracnose pathogen, Colletotrichum lindemuthianum race β. Initial disease incidence was highest in the chiseled plots, where more bean debris was left on the surface than in the other treatments. Significantly higher final disease incidence and area under the disease progress curve (AUDPC) occurred in the chiseled plots than in the rototilled and moldboard plowed plots. There was a significant correlation (r = 0.75) between the percentage of debris left on the surface and subsequent disease incidence on pods in the field. Anthracnose incidence or severity in the field was highly correlated with disease incidence on harvested pods (r values ranged between 0.87 and 0.98). Results from the ordinary runs analysis showed that anthracnose occurred randomly within the field early in the season, indicating that initial inoculum was from bean debris within the field. Later in the season, plant-to-plant spread resulted in a more clustered distribution of diseased plants.
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Affiliation(s)
- N Ntahimpera
- Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva 14456
| | - H R Dillard
- Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva 14456
| | - A C Cobb
- Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva 14456
| | - R C Seem
- Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva 14456
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Pearson RC, Aldwinckle HS, Seem RC. Teliospore germination and basidiospore formation in Gymnosporangium juniperi-virginianae: a regression model of temperature and time effects. ACTA ACUST UNITED AC 1977. [DOI: 10.1139/b77-321] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The influence of temperature on teliospore germination and basidiospore formation in Gymnosporangium juniperi-virginianae was studied in vitro. Teliospores germinated from 8 to 30 °C. Germination was first observed after 2 h from 12–28 °C but longer periods were required at lower temperatures. Promycelia formed basidiospores by 4 h from 12 to 24 °C but not until 7 h at 8 °C. Abortive germination of teliospores, without production of basidiospores, occurred from 26 to 30 °C. No germination was observed from 2 to 6 °C. Multiple regression analyses were performed and an equation relating germination of teliospores to temperature and time was formulated.
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