scholarly journals Bermudagrass Resistance to Spring Dead Spot Caused by Ophiosphaerella herpotricha

Plant Disease ◽  
1998 ◽  
Vol 82 (7) ◽  
pp. 771-774 ◽  
Author(s):  
J. H. Baird ◽  
D. L. Martin ◽  
C. M. Taliaferro ◽  
M. E. Payton ◽  
N. A. Tisserat
Keyword(s):  
Field Study ◽  
Disease Severity ◽  
Shoot Density ◽  
Root Weight ◽  
Spring Dead Spot ◽  
Ophiosphaerella Herpotricha ◽  
Cynodon Transvaalensis ◽  
Field Plots

Field and greenhouse studies were conducted to evaluate the resistance of seed- and vegetatively propagated bermudagrass entries (Cynodon spp.) to spring dead spot caused by Ophiosphaerella herpotricha. In Kansas greenhouse studies, O. herpotricha caused root discoloration and root weight reductions in all entries tested. However, in Kansas field plots, root weight reductions were not different among entries and were not correlated with disease severity ratings. In an inoculated field study in Oklahoma, diseased areas ranged from 47 cm2 for the entry Jackpot to 262 cm2 for Poco Verde in 1995, and from 121 to 1,810 cm2 for the entries Guymon and Common in 1996. African bermudagrass (Cynodon transvaalensis) exhibited the greatest number of live shoots per diseased area in both years, due in part to its greater shoot density, but also indicating greater potential to recover from the disease. African bermudagrass, Guymon, Sundevil, Midlawn, Midfield, Ft. Reno, Mirage, and several experimental seed-propagated entries were most resistant to spring dead spot, having the lowest diseased area and greatest number of live shoots within diseased areas. In Oklahoma, severity of spring dead spot among bermudagrass entries was correlated with feeeze injury that occurred during the first winter after planting.

scholarly journals Infection and Colonization of Turf-Type Bermudagrass by Ophiosphaerella herpotricha Expressing Green or Red Fluorescent Proteins

2010 ◽  
Vol 100 (5) ◽  
pp. 415-423 ◽  
Author(s):  
Oliver C. Caasi ◽  
Nathan R. Walker ◽  
Stephen M. Marek ◽  
James N. Enis ◽  
Thomas K. Mitchell
Keyword(s):  
Fluorescent Proteins ◽  
The United States ◽  
Cellular Level ◽  
Green Fluorescent Proteins ◽  
Limited Information ◽  
Spring Dead Spot ◽  
Red Fluorescent Proteins ◽  
Root Necrosis ◽  
Ophiosphaerella Herpotricha ◽  
Green Fluorescent

Spring dead spot, caused by Ophiosphaerella herpotricha, is the most important disease of turf-type bermudagrass (Cynodon spp.) in the transition zone of the United States. Despite the importance of the disease, only limited information is available about the host–pathogen interaction at the cellular level. To evaluate the host plant interaction, an isolate of O. herpotricha expressing green fluorescent proteins (GFP) or red fluorescent proteins (tdTomato) was used to study the infection and colonization of roots and stolons of several bermudagrass cultivars. Roots of cultivars Tifway 419 and Midlawn were colonized similarly, resulting in extensive root necrosis, whereas an accession of Cynodon transvaalensis was less necrotic. The stele of C. transvaalensis roots was colonized but not those of Tifway 419 and Midlawn. For intact stolons, colonization was limited to the epidermis and defined macroscopic necrotic lesions were observed on Tifway 419 and Midlawn while C. transvaalensis stolon tissues remained mostly nonnecrotic. Internal colonization of stolons occurred when hyphae grew into wounds, resulting in necrosis in Tifway 419 and Midlawn, but not in C. transvaalensis. These studies suggest that the interaction of O. herpotricha with bermudagrass varies across host genotypes and the host tissues infected. The limited necrosis in C. transvaalensis tissues, though colonized, suggests an inherent tolerance to O. herpotricha.

A comparison of field inoculation methods with Cercosporella herpotrichoides (Fron) on spring barley

1969 ◽  
Vol 73 (3) ◽  
pp. 437-444 ◽  
Author(s):  
D. Gareth Jones ◽  
J. M. L. Davies
Keyword(s):  
Grain Yield ◽  
Disease Severity ◽  
Disease Incidence ◽  
Spring Barley ◽  
Barley Variety ◽  
Field Inoculation ◽  
Inoculation Methods ◽  
Field Plots

SUMMARYA comparison was made of six different methods of inoculation with Cercosporella herpotrichoidesFron on field plots of the spring barley variety Impala. All inoculation treatments produced significant differences in terms of disease incidence and grain yield compared with the uninoculated controls. Significant differences were found between treatments in terms of disease incidence, disease severity, mean yield/head and 1000 grain weights. The time of inoculation was also found to be significant. The earlier inoculation caused a reduction in yield of approximately 66 % compared with 50 % at the later inoculation. The application of these methods is discussed.

scholarly journals Suppression of Sclerotinia Stem Rot of Soybean by Lactofen Herbicide Treatment

1999 ◽  
Vol 89 (7) ◽  
pp. 598-602 ◽  
Author(s):  
E. K. Dann ◽  
B. W. Diers ◽  
R. Hammerschmidt
Keyword(s):  
Disease Severity ◽  
Field Experiments ◽  
Lesion Size ◽  
Stem Rot ◽  
Growth Stages ◽  
Sclerotinia Stem Rot ◽  
High Disease Severity ◽  
Disease Pressure ◽  
Seed Yields ◽  
Field Plots

Severity of Sclerotinia stem rot of soybean after treatment with lactofen (Cobra) and other herbicides was assessed in field experiments conducted in Michigan from 1995 to 1997. At sites where disease pressure was high, disease severity was reduced 40 to 60% compared with controls when lactofen was applied at the V3 (1995 and 1996) or R1 (1997) growth stages. Corresponding seed yields were unchanged or up to 20% greater when lactofen was applied at the R1 stage in 1997. Disease severity was not reduced by lactofen treatments in years and at sites where disease pressure was low to medium, and corresponding yields often were reduced by ≈10%. High levels of glyceollin accumulated in lactofen-injured leaves collected from field plots in 1996 and 1997. High glyceollin content in lactofen-treated leaves was associated with significant reductions in lesion size when leaves were challenge-inoculated with Sclerotinia sclerotiorum.

scholarly journals Response of Ancestral Soybean Lines and Commercial Cultivars to Rhizoctonia Root and Hypocotyl Rot

Plant Disease ◽  
2001 ◽  
Vol 85 (10) ◽  
pp. 1091-1095 ◽  
Author(s):  
C. A. Bradley ◽  
G. L. Hartman ◽  
R. L. Nelson ◽  
D. S. Mueller ◽  
W. L. Pederson
Keyword(s):  
Rhizoctonia Solani ◽  
Disease Severity ◽  
Partial Resistance ◽  
Common Disease ◽  
Root Weight ◽  
Soybean Cultivars ◽  
Commercial Cultivars ◽  
Maturity Groups

Rhizoctonia root and hypocotyl rot is a common disease of soybean caused by Rhizoctonia solani. There are no commercial cultivars marketed as resistant to Rhizoctonia root and hypocotyl rot, and only a few sources of partial resistance to this disease have been reported. Ninety ancestral soybean lines, maturity groups (MGs) 000 to X, and 700 commercial cultivars, MGs II to IV, were evaluated for resistance to R. solani under greenhouse conditions. Most of the ancestral lines and cultivars evaluated were susceptible; however, 21 of the ancestral lines and 20 of the commercial cultivars were partially resistant. Of the 21 ancestral lines, CNS, Mandarin (Ottawa), and Jackson are in the pedigree of cultivars previously reported as being partially resistant to R. solani. In an additional study, dry root weights of 21 soybean cultivars were evaluated after inoculation with R. solani. Variation in dry root weight occurred among cultivars, but there was not a significant (P = 0.05) correlation between dry root weight and disease severity.

scholarly journals Root Weight, Nonstructural Carbohydrate Content, and Shoot Density of High-density Creeping Bentgrass Cultivars

HortScience ◽  
2001 ◽  
Vol 36 (2) ◽  
pp. 368-370 ◽  
Author(s):  
Patricia Sweeney ◽  
Karl Danneberger ◽  
Daijun Wang ◽  
Michael McBride
Keyword(s):  
Creeping Bentgrass ◽  
Dry Weight ◽  
The United States ◽  
Shoot Density ◽  
Root Weight ◽  
Limited Information ◽  
Putting Greens ◽  
Cultivar Group ◽  
Nonstructural Carbohydrate ◽  
Carbohydrate Levels

Limited information is available on the performance under temperate conditions in the United States of recently released cultivars of creeping bentgrass (Agrostis stolonifera L.) with high shoot density for use on golf course putting greens. Fifteen cultivars were established in Aug. 1996 on a greens mix with high sand content to compare their seasonal weights and total nonstructural carbohydrate (TNC) contents. The cultivars were maintained at 3.1 mm height of cut. Shoot density counts were taken during Apr., July, and Oct. 1998. Root weights and nonstructural carbohydrate levels were assessed monthly from June 1997 through Nov. 1998. A cultivar group contrast between the high shoot density cultivars (`Penn A1', `Penn A2', `Penn A4', `Penn G1', `Penn G2', and `Penn G6') and the standard cultivars (`Penncross', `Crenshaw', `Southshore', `DF-1', `Procup', `Lopez', `SR1020', and `Providence') revealed that the former averaged 342.9 and 216.1 more shoots/dm2 on two of the three sampling dates. Root dry weights did not vary significantly (P ≤ 0.05) among the cultivars. Performing a contrast between new high shoot density cultivars and standard cultivars revealed greater root dry weight in the former during Mar. and May 1998. Differences (P ≤ 0.05) in TNC were observed on two of the 18 sampling dates, but no trends were evident.

Rubidium Marking to Detect Dispersal of Pest and Predator from Corn into Sorghum and Cotton in Georgia

2007 ◽  
Vol 42 (3) ◽  
pp. 383-391 ◽  
Author(s):  
P. G. Tillman ◽  
J. R. Prasifka ◽  
K. M. Heinz
Keyword(s):  
Field Study ◽  
Helicoverpa Zea ◽  
Cotton Field ◽  
Orius Insidiosus ◽  
Field Site ◽  
Rubidium Chloride ◽  
Common Boundary ◽  
Field Plots

This field study evaluated marking both the pest [Helicoverpa zea (Boddie)] and its predator [Orius insidiosus (Say)] with rubidium chloride (RbCI) in corn to detect dispersal of these insects from this crop into sorghum and cotton. Sorghum and cotton were planted in small plots at the interface, or common boundary, of a commercial corn and cotton field. The cotton field adjacent to these interface plots was divided into cotton field plots. Foliar solutions of RbCI were applied to corn at field site 1 when the ears were infested with 4th through 6th instars of H. zea and at site 2 when corn silks were infested with eggs and 1st instars of H. zea and nymphs and adults of O. insidiosus. Insects were collected at various times after RbCI application from the sorghum interface plots, cotton interface plots, and cotton field plots. Both H. zea eggs and O. insidiosus females were successfully marked in corn treated with RbCI, and marking success for both insects ranged from 15–33%. Data on rubidium-marked insects indicated that H. zea females from the generation feeding on rubidium-treated corn dispersed into sorghum interface plots at both treated sites and into cotton interface plots at one site and that O. insidiosus females dispersed from corn into sorghum interface plots and cotton field plots at one site.

scholarly journals Susceptibility of Populus balsamifera to Septoria musiva: A Field Study and Greenhouse Experiment

Plant Disease ◽  
2009 ◽  
Vol 93 (11) ◽  
pp. 1146-1150 ◽  
Author(s):  
Jared M. LeBoldus ◽  
Peter V. Blenis ◽  
Barb R. Thomas ◽  
Nicolas Feau ◽  
Louis Bernier
Keyword(s):  
Field Study ◽  
Disease Severity ◽  
Dna Sequences ◽  
Hybrid Poplar ◽  
Small Subunit ◽  
Populus Balsamifera ◽  
Septoria Musiva ◽  
Polymerase Chain ◽  
Northern Alberta ◽  
Small Subunit Ribosomal Dna

A greenhouse inoculation experiment and field study were conducted to determine the cause of an outbreak of Septoria musiva cankers on Populus balsamifera in a northern Alberta plantation. Four clones of P. balsamifera, five clones of putatively resistant P. deltoides, and one susceptible hybrid poplar clone, Northwest, were inoculated with seven isolates identified as S. musiva. Four of the isolates were from P. balsamifera in Alberta and the others were from P. deltoides in Quebec. Results indicated that disease severity was similar for Alberta and Quebec isolates (P = 0.243) and that P. balsamifera had the greatest mean disease severity (x-bar = 4.20), P. deltoides had the lowest (x-bar = 2.76), and Northwest was intermediate (x-bar = 3.45). A genetic analysis comparing six polymorphic polymerase chain reaction restriction fragment length polymorphism loci and the mitochondrial small subunit ribosomal DNA sequences of the seven isolates indicated that the Alberta population was made up of at least three distinct genotypes. Canker incidence and age on Northwest and 56 different clones of P. balsamifera in a plantation were recorded. Canker incidence (P = 0.726) and the canker age distributions (P = 0.994) were similar for the two species. In conclusion, contrary to what has been reported in the literature, P. balsamifera appears to be quite susceptible to Septoria canker.

scholarly journals Accounting for the Economic Risk Caused by Variation in Disease Severity in Fungicide Dose Decisions, Exemplified for Mycosphaerella graminicola on Winter Wheat

2013 ◽  
Vol 103 (7) ◽  
pp. 666-672 ◽  
Author(s):  
D. E. te Beest ◽  
N. D. Paveley ◽  
M. W. Shaw ◽  
F. van den Bosch
Keyword(s):  
Probability Distribution ◽  
Risk Aversion ◽  
Disease Severity ◽  
Yield Loss ◽  
Grain Filling ◽  
Optimal Dose ◽  
Mycosphaerella Graminicola ◽  
Septoria Tritici ◽  
High Loss ◽  
Field Plots

A method is presented to calculate economic optimum fungicide doses accounting for the risk aversion of growers responding to variability in disease severity between crops. Simple dose-response and disease-yield loss functions are used to estimate net disease-related costs (fungicide cost plus disease-induced yield loss) as a function of dose and untreated severity. With fairly general assumptions about the shapes of the probability distribution of disease severity and the other functions involved, we show that a choice of fungicide dose which minimizes net costs, on average, across seasons results in occasional large net costs caused by inadequate control in high disease seasons. This may be unacceptable to a grower with limited capital. A risk-averse grower can choose to reduce the size and frequency of such losses by applying a higher dose as insurance. For example, a grower may decide to accept “high-loss” years 1 year in 10 or 1 year in 20 (i.e., specifying a proportion of years in which disease severity and net costs will be above a specified level). Our analysis shows that taking into account disease severity variation and risk aversion will usually increase the dose applied by an economically rational grower. The analysis is illustrated with data on Septoria tritici leaf blotch of wheat caused by Mycosphaerella graminicola. Observations from untreated field plots at sites across England over 3 years were used to estimate the probability distribution of disease severities at mid-grain filling. In the absence of a fully reliable disease forecasting scheme, reducing the frequency of high-loss years requires substantially higher doses to be applied to all crops. Disease-resistant cultivars reduce both the optimal dose at all levels of risk and the disease-related costs at all doses.

scholarly journals Effect of Cold Acclimation and Freezing on Spring Dead Spot Severity in Bermudagrass

HortScience ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 421-423 ◽  
Author(s):  
F.B. Iriarte ◽  
J.D. Fry ◽  
D.L Martin ◽  
T.C. Todd ◽  
N.A. Tisserat
Keyword(s):  
Cold Acclimation ◽  
Disease Severity ◽  
Incubation Temperature ◽  
Freezing Temperature ◽  
Spring Dead Spot ◽  
Freezing Temperatures ◽  
Shoot Mortality

Spring dead spot (SDS), caused by three root-infecting species of Ophiosphaerella, is a destructive disease of bermudagrass (Cynodon spp.L.C. Rich). We tested the effects of incubation temperature and duration, and exposure to decreasing freezing temperatures on bermudagrass shoot survival following inoculation with SDS pathogens. Inoculated plants exposed to freezing temperatures as high as -2 °C following a two month incubation exhibited extensive shoot mortality and had SDS symptoms consistent with those observed in the field. Lowering the freezing temperature from -2 to -8 °C increased disease severity and shoot mortality on noninoculated bermudagrass. Inoculated bermudagrass incubated for 1 month in the greenhouse, then for an additional month at 4 °C had greater shoot mortality following freezing than plants incubated at 25 °C. Although cold acclimation and freezing intensified SDS symptoms, the technique did not reliably distinguish between resistant and susceptible cultivars.

Geographic Distribution of Ophiosphaerella Species in the Mid-Atlantic United States

2021 ◽  
Author(s):  
Wendell Joseph Hutchens ◽  
Caleb Henderson ◽  
Elizabeth A Bush ◽  
James Kerns ◽  
David McCall
Keyword(s):  
United States ◽  
North Carolina ◽  
Geographic Distribution ◽  
Management Practices ◽  
Cynodon Dactylon ◽  
Spring Dead Spot ◽  
Athletic Fields ◽  
Survey Results ◽  
Ophiosphaerella Herpotricha ◽  
Species Specific

Spring dead spot (SDS) of bermudagrass (Cynodon dactylon) is primarily caused by Ophiosphaerella herpotricha and Ophiosphaerella korrae in North America. These two species respond differently to numerous management practices, grow optimally at different soil pH ranges, and differ in aggressiveness. Understanding the Ophiosphaerella species distribution in regions where SDS occurs will allow turfgrass managers to tailor their management practices toward the predominant species present. A survey was conducted in the Mid-Atlantic United States in which one to 14 samples of bermudagrass expressing SDS symptoms were taken from 51 athletic fields, golf courses, or sod farms across Delaware, Maryland, North Carolina, and Virginia. DNA was isolated from necrotic root and stolon tissue, amplified using species-specific primers, and detected in a real-time PCR assay. At least one isolate of O. herpotricha was recovered from 76% of the locations and O. korrae was recovered from 73% of the locations. Ophiosphaerella herpotricha was amplified from 55% of the samples while O. korrae was amplified from 37% of the samples. There were distinct regions in the Mid-Atlantic in which either O. herpotricha or O. korrae was predominant. Ophiosphaerella herpotricha was predominant in western Virginia, central North Carolina as well as Delaware and eastern Maryland. However, O. korrae was predominant in central Maryland and Virginia as well as eastern Virginia and North Carolina. Ophiosphaerella herpotricha was isolated from certain cultivars more frequently than O. korrae and vice versa. These survey results elucidate the geographic distribution of O. herpotricha and O. korrae throughout the Mid-Atlantic United States.

Sign in / Sign up

Export Citation Format

Share Document