A Rainfall-Based Model for Predicting the Regional Incidence of Wheat Seed Infection by Stagonospora nodorum in New York

2010 ◽  
pp. 1263-1280
Keyword(s):  
New York ◽  
Stagonospora Nodorum ◽  
Seed Infection ◽  
Wheat Seed

scholarly journals A Rainfall-Based Model for Predicting the Regional Incidence of Wheat Seed Infection by Stagonospora nodorum in New York

2002 ◽  
Vol 92 (5) ◽  
pp. 511-518 ◽  
Author(s):  
Denis A. Shah ◽  
Gary C. Bergstrom
Keyword(s):  
New York ◽  
Simple Model ◽  
Stagonospora Nodorum ◽  
Seed Infection ◽  
Independent Data ◽  
Wheat Seed ◽  
Binomial Probability ◽  
Actual Distribution ◽  
Central New York ◽  
Distribution Parameters

Our goal was to develop a simple model for predicting the incidence of wheat seed infection by Stagonospora nodorum across western and central New York in any given year. The distribution of the incidence of seed infection by S. nodorum across the region was well described by the beta-binomial probability distribution (parameters p and θ). Mean monthly rainfalls in May and in June across western and central New York were used to predict p. The binary power law was used to predict θ. The model was validated with independent data collected from New York. The predicted distribution of seed infection incidence was not statistically different from the actual distribution of the incidence of seed infection.

Infection of wheat seed by Pyrenophora tritici-repentis

1994 ◽  
Vol 72 (4) ◽  
pp. 510-519 ◽  
Author(s):  
A. M. C. Schilder ◽  
G. C. Bergstrom
Keyword(s):  
New York ◽  
Flag Leaf ◽  
Infection Process ◽  
Tan Spot ◽  
Seed Infection ◽  
Wheat Seed ◽  
Inoculum Concentration ◽  
Pyrenophora Tritici Repentis ◽  
Key Words Wheat ◽  
Late Stages

The seed infection process of Pyrenophora tritici-repentis, incitant of tan spot of wheat, was investigated, as were several influencing factors. Following inoculation of the wheat spike, P. tritici-repentis gained access to the seed by first colonizing the glume, lemma, or palea. Seed infection was first observed 3 d after inoculation, and infection incidence increased with time and with inoculum concentration. Wheat seeds were susceptible to infection by this fungus throughout most of their development, although inoculation at the milk stage resulted in the highest percentage of infected seeds. Susceptibility to foliar infection by P. tritici-repentis was not a good predictor of susceptibility to seed infection in four wheat cultivars tested in a glasshouse experiment, except perhaps in ‘BR 8’, which was significantly less susceptible than the other cultivars at early and late stages of seed development. In a field experiment, wheat seed infection by P. tritici-repentis occurred primarily after the early dough stage and was positively correlated with tan spot severity on the flag leaf shortly after anthesis. Key words: wheat, Pyrenophora tritici-repentis, Drechslera tritici-repentis, tan spot, seed infection, New York.

scholarly journals Differential Seed Infection of Wheat Cultivars by Stagonospora nodorum

Plant Disease ◽  
2000 ◽  
Vol 84 (7) ◽  
pp. 749-752 ◽  
Author(s):  
Denis A. Shah ◽  
Gary C. Bergstrom ◽  
Mark E. Sorrells
Keyword(s):  
New York ◽  
Winter Wheat ◽  
Agar Medium ◽  
Stagonospora Nodorum ◽  
Seed Infection ◽  
Wheat Cultivars ◽  
Production Environment ◽  
Flag Leaves ◽  
Initial Inoculum ◽  
Relative Susceptibility

Seed of soft white winter wheat collected from New York regional cultivar trials in 1995 and 1996 were assayed on an agar medium selective for Stagonospora nodorum. Incidence of seed infection varied with production environment. Relative incidence of seed infection differed significantly among cultivars and was consistent across environments. The flag leaves and ears of 12 cultivars were inoculated quantitatively at flowering in a glasshouse. Cultivars did not differ significantly in disease on the flag leaves. Incidence of seed infection for all cultivars was above 60%, but was significantly lower in Delaware and Houser than in other cultivars. Results confirm that wheat cultivars differ in their relative susceptibility to seed infection by S. nodorum. Resistance in wheat to seed infection by S. nodorum may be a useful mechanism for reducing initial inoculum in areas where infected seed is considered the primary inoculum source for Stagonospora nodorum blotch.

scholarly journals PCR-Based Detection of Cephalosporium gramineum in Winter Wheat

Plant Disease ◽  
2012 ◽  
Vol 96 (3) ◽  
pp. 437-442 ◽  
Author(s):  
K. L. E. Klos ◽  
L. M. Vásquez-Siller ◽  
H. C. Wetzel ◽  
T. D. Murray
Keyword(s):  
Winter Wheat ◽  
Internal Transcribed Spacer ◽  
Seed Infection ◽  
Wheat Seed ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Internal Transcribed Spacer Region ◽  
Polymerase Chain ◽  
Cephalosporium Gramineum ◽  
Field Plots

A polymerase chain reaction (PCR) assay was developed amplifying a 496-bp fragment of the internal transcribed spacer region of Cephalosporium gramineum genomic DNA at concentrations of 100 fg/μl. Winter wheat seed and seedlings were collected from field plots where C. gramineum was present. Seed was tested by PCR using 20-seed samples bulked for DNA extraction. Estimates of seed infection, based on isolation of the pathogen on semiselective medium and PCR, were comparable at 0.18 and 0.13% of winter wheat ‘Stephens’ (P = 0.6042), and 0.45 and 0.58% of experimental line WA7970 (P = 0.5636), respectively. PCR differentiated between plants with well-developed symptoms of Cephalosporium stripe and noninoculated plants. Positive PCR was obtained from 22% of asymptomatic leaf blades from inoculated plants. We found no false positives when PCR and C. gramineum isolation on a semiselective medium were performed using tissue from the same leaf. The PCR assay has potential to diagnose Cephalosporium stripe disease prior to the appearance of symptoms. Negative PCR for some samples from which C. gramineum was isolated suggests that C. gramineum may be present below the level of detection in some asymptomatic leaves. This PCR assay may be useful for investigations into C. gramineum infection of wheat.

scholarly journals Tomato Fruit and Seed Colonization by Clavibacter michiganensis subsp. michiganensis through External and Internal Routes

2013 ◽  
Vol 79 (22) ◽  
pp. 6948-6957 ◽  
Author(s):  
Matthew A. Tancos ◽  
Laura Chalupowicz ◽  
Isaac Barash ◽  
Shulamit Manulis-Sasson ◽  
Christine D. Smart
Keyword(s):  
New York ◽  
Fluorescent Protein ◽  
Tomato Fruit ◽  
Active Movement ◽  
Seed Infection ◽  
Clavibacter Michiganensis ◽  
Gene Encoding ◽  
Content Type ◽  
Clavibacter Michiganensis Subsp ◽  
Green Fluorescent

ABSTRACTThe Gram-positive bacteriumClavibacter michiganensissubsp.michiganensis, causal agent of bacterial wilt and canker of tomato, is an economically devastating pathogen that inflicts considerable damage throughout all major tomato-producing regions. Annual outbreaks continue to occur in New York, whereC. michiganensissubsp.michiganensisspreads via infected transplants, trellising stakes, tools, and/or soil. Globally, new outbreaks can be accompanied by the introduction of contaminated seed stock; however, the route of seed infection, especially the role of fruit lesions, remains undefined. In order to investigate the modes of seed infection, New YorkC. michiganensissubsp.michiganensisfield strains were stably transformed with a gene encoding enhanced green fluorescent protein (eGFP). A constitutively eGFP-expressing virulentC. michiganensissubsp.michiganensisisolate, GCMM-22, was used to demonstrate thatC. michiganensissubsp.michiganensiscould not only access seeds systemically through the xylem but also externally through tomato fruit lesions, which harbored high intra- and intercellular populations. Active movement and expansion of bacteria into the fruit mesocarp and nearby xylem vessels followed, once the fruits began to ripen. These results highlight the ability ofC. michiganensissubsp.michiganensisto invade tomato fruits and seeds through multiple entry routes.

scholarly journals Triazole Seed Treatments Suppress Spore Production by Puccinia recondita, Septoria tritici, and Stagonospora nodorum from Wheat Leaves

Plant Disease ◽  
1999 ◽  
Vol 83 (4) ◽  
pp. 328-332 ◽  
Author(s):  
D. R. Sundin ◽  
W. W. Bockus ◽  
M. G. Eversmeyer
Keyword(s):  
Linear Models ◽  
Spore Production ◽  
Septoria Tritici ◽  
Stagonospora Nodorum ◽  
Puccinia Recondita ◽  
Wheat Seed ◽  
Wheat Seedlings ◽  
Asexual Sporulation ◽  
Treated Seed ◽  
Wheat Leaves

Treatments of winter wheat seed with the systemic triazole fungicides triadimenol (31 g a.i./100 kg = Baytan 30F at 1.5 fl oz/cwt) and difenoconazole (24 g a.i./100 kg = Dividend 3FS at 1.0 fl. oz/cwt) were tested for effect on asexual sporulation by Puccinia recondita, Septoria tritici, and Stagonospora nodorum. Spore production was measured on seedlings grown in a growth chamber (24°C day/15°C night, 12-h photoperiod) and inoculated with the pathogens 3, 5, or 7 weeks after sowing. Spore production was converted to a percentage of the non-treated control and regressed against weeks after planting when plants were inoculated. Linear models fit data for both fungicides against all three pathogens. According to the models, difenoconazole suppressed sporulation levels of P. recondita and Septoria tritici to 10% of the levels on plants from non-treated seed for about 3 weeks after sowing. Spore production for all three fungi was suppressed to 25% of the non-treated level for at least 4.2 weeks and to 50% for at least 6.5 weeks. Similarly, triadimenol suppressed all three pathogens to 50% of the non-treated level for at least 3.2 weeks. The two fungicides showed similar effects against S. tritici; however, difenoconazole showed significantly greater suppression of sporulation by P. recondita and Stagonospora nodorum compared with triadimenol. Responses occurred even though large concentrations of spores were used to inoculate plants and environmental conditions were optimized for spore production. Reduced sporulation should help protect fall-planted wheat seedlings and may significantly delay epidemics in the following spring.

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