EPIDEMIOLOGY AND CONTROL OF ASCOCHYTA PINODES ON FIELD PEAS IN CANADA

1967 ◽  
Vol 47 (4) ◽  
pp. 395-403 ◽  
Author(s):  
V. R. Wallen ◽  
T. F. Cuddy ◽  
P. N. Grainger
Keyword(s):  
Sandy Loam ◽  
Mycosphaerella Pinodes ◽  
Optimum Range ◽  
Field Peas ◽  
Different Temperatures ◽  
Ascochyta Pinodes ◽  
Ascochyta Pisi ◽  
And Control ◽  
Pea Seed ◽  
Better Than

Blight, caused by Mycosphaerella pinodes, is now epiphytotic and Ascochyta pinodes is the principal pathogen found in Canadian field pea seed. Ascochyta pisi, cause of leaf and pod spot of peas and formerly the principal seed-borne pathogen, is now seldom found. Reasons for this situation are discussed. Although infection by A. pinodes, from the seed to seedling stage, took place over a temperature range of 10 to 30 °C, the optimum range for infection was 15 to 18 °C. The symptoms produced at the different temperatures are described. Thiram 75, Orthocide 75, Panogen 15 and Spergon as seed treatments were effective in controlling the organism in sand, sandy loam and sterilized sandy loam. Thiram 75 and Orthocide 75 were equal in effectiveness and significantly better than Panogen 15 or Spergon.

The epidemiology and control of ascochyta blight in field peas: a review

2006 ◽  
Vol 57 (8) ◽  
pp. 883 ◽  
Author(s):  
T. W. Bretag ◽  
P. J. Keane ◽  
T. V. Price
Keyword(s):  
Current Knowledge ◽  
Ascochyta Blight ◽  
Mycosphaerella Pinodes ◽  
Sources Of Resistance ◽  
New Crops ◽  
Field Peas ◽  
Ascochyta Pisi ◽  
Almost All ◽  
The Cost ◽  
And Control

Ascochyta blight is one of the most important diseases affecting field peas. The disease occurs in almost all pea-growing regions of the world and can cause significant crop losses when conditions are favourable for an epidemic. Here we review current knowledge of the epidemiology of the disease. Details are provided of disease symptoms, the disease cycle and the taxonomy of the causal fungi, Ascochyta pisi, Mycosphaerella pinodes and Phoma pinodella. The importance of seed-, soil- and air-borne inoculum is discussed along with the factors that influence survival of the causal fungi in soil, on seed or associated with pea trash. Many studies have been reviewed to establish how the fungi responsible for the disease survives from year to year, how the disease becomes established in new crops and the conditions that favour disease development. Evidence is provided that crop rotation, destruction of infected pea trash and chemical seed treatments can significantly reduce the amount of primary inoculum. Later sowing of crops has been shown to reduce the incidence and severity of disease. Fungicides have been used successfully to control the disease, although the cost of their application can significantly reduce the profitability of the crop. The best long-term strategy for effective disease control appears to be the development of ascochyta blight resistant pea varieties. Reports of physiological specialisation in ascochyta blight fungi are also documented. Despite extensive screening of germplasm, relatively few sources of resistance to ascochyta blight fungi have been found in Pisum sativum. However, the discovery of much better sources of resistance in closely related species and the development of advanced breeding methods offer new possibilities for developing useful resistance.

Importance of seed-borne inoculum in the etiology of the Ascochyta blight complex of field peas (Pisum sativum L.) grown in Victoria

1995 ◽  
Vol 35 (4) ◽  
pp. 525 ◽  
Author(s):  
TW Bretag ◽  
TV Price ◽  
PJ Keane
Keyword(s):  
Pisum Sativum ◽  
Ascochyta Blight ◽  
Mycosphaerella Pinodes ◽  
Seed Infection ◽  
Seeding Rate ◽  
Pisum Sativum L ◽  
Field Peas ◽  
Ascochyta Pisi ◽  
Growing Region ◽  
Seed Infestation

Fungi associated with the ascochyta blight complex of field peas were isolated from 436 of 691 seedlots tested. Of the fungi detected, 94.8% of isolates were Mycosphaerella pinodes, 4.2% Phoma medicaginis, and 1.0% Ascochyta pisi. The levels of infestation of seed varied considerably from year to year and between seedlots, depending on the amount of rainfall between flowering and maturity. Within a particular pea-growing region, the level of seed-borne infection was often highest in seed from crops harvested latest. In addition, crops sown early were usually more severely affected by disease than late-sown crops, and this resulted in higher levels of seed infection. There was no correlation between the level of seed infestation by M. pinodes and the severity of ascochyta blight; however, where the level of seed infection was high (>11%) there was a significant reduction in emergence, which caused a reduction in grain yield. It may therefore be possible to use seed with high levels of seed-borne ascochyta blight fungi, provided the seeding rate is increased to compensate for poor emergence.

The Liege Vacuum Optical Bench ‘Focal 5’

1987 ◽  
Vol 30 (4) ◽  
pp. 17-20
Author(s):  
D. Macau-Hercot ◽  
A. Cucchiaro ◽  
J. Macau ◽  
J. Jamar ◽  
C. Jamar
Keyword(s):  
Vacuum Chamber ◽  
Thermal Environment ◽  
Space Environment ◽  
Cylindrical Shape ◽  
Thermal Vacuum ◽  
Different Temperatures ◽  
Optical Table ◽  
And Control ◽  
Vacuum Space ◽  
Better Than

Focal is a facility designed to perform optical tests on payloads in a thermal vacuum space environment. The vacuum chamber is a vessel of horizontal cylindrical shape having 5 m (16.4 ft) diameter and 6 m (19.7 ft) length. The vacuum limit is about 1 nbar. Inside the vessel an optical table ensures a stability better than 10 μg. A thermal environment is simulated by shrouds specific to each experiment. The thermal facilities allow the feeding and control of 10 independent shrouds at 10 different temperatures between 170K (-153°F) and 370K (206°F) with a stability of 0.1 K (0.18°F). This facility has been used for the thermal vacuum and thermal balance tests of the ESA Hipparcos astrometry payload.

Characterization and Control of Erwinia spp. and Pluralibacter sp. in Tuna Salad Preparations

2019 ◽  
Vol 82 (6) ◽  
pp. 1071-1081
Author(s):  
KRISTIN BJORNSDOTTIR-BUTLER ◽  
SUSAN McCARTHY ◽  
RONALD A. BENNER
Keyword(s):  
Growth Conditions ◽  
Whole Genome ◽  
Processing Conditions ◽  
Optimum Growth ◽  
Significant Growth ◽  
Ph Values ◽  
Histamine Production ◽  
Different Temperatures ◽  
And Control ◽  
Erwinia Persicina

ABSTRACT Histamine-producing Erwinia and Pluralibacter spp. capable of producing toxic histamine levels were isolated from ingredients commonly used in tuna salad preparations. The characterization and control of these histamine-producing bacteria are necessary to prevent illness from tuna salad consumption. We confirmed the identity of two Erwinia spp. and one Pluralibacter sp. previously isolated from tuna salad ingredients through whole genome sequencing and phylogenic analysis and characterized them for growth and histamine production at different temperatures, pH values, and salt concentrations. In addition, we examined the effects of dried vinegar (DV) powder on growth and histamine production of these strains in inoculated tuna salad preparations. Optimum growth temperatures in tryptic soy broth (TSB) for the two Erwinia spp. and one Pluralibacter sp. were 30.1, 31.1, and 33.9°C, respectively, and growth in TSB was observed at 5°C for both genera. Optimum histamine production of Erwinia persicina, Erwinia spp., and Pluralibacter spp. in TSB with histidine occurred from 25 to 30°C, pH 4 to 6, and 0 to 4% NaCl. No significant growth or histamine production was observed in tuna salad preparations stored at 4°C. Growth and histamine production by Erwinia or Pluralibacter spp. was inhibited in tuna salad containing celery and onion and 2% DV, whereas significant growth and histamine production occurred in tuna salad without DV. Understanding optimum growth conditions and histamine production can provide guidance to tuna salad manufacturers in formulating products and adjusting processing conditions that minimize hazards from these histamine-producing bacteria. Addition of 2% DV to tuna salad preparations may prevent histamine production in the event of temperature abuse. HIGHLIGHTS

Serological differentiation of the Ascochyta species on peas

1968 ◽  
Vol 14 (4) ◽  
pp. 449-451 ◽  
Author(s):  
C. Madhosingh ◽  
V. R. Wallen
Keyword(s):  
Immune Serum ◽  
Complex Pattern ◽  
Serological Relationship ◽  
Agar Gel ◽  
Ascochyta Pinodes ◽  
Ascochyta Pisi ◽  
Precipitation Reactions ◽  
Species Specific ◽  
Specific Reactions

Specific immune serum against Ascochyta pisi was developed and three species-specific reactions were obtained by standard absorption techniques using extracts of both Ascochyta pinodella and Ascochyta pinodes. Ouchterlony tests showed a complex pattern of precipitation reactions in agar gel between the antigens from the three species and antisera developed in response to them and indicated distinct serological relationships among the three fungi. The pattern of reciprocal precipitin reactions indicates a closer serological relationship between A. pinodella and A. pinodes than between either of these two species and A. pisi. Two serologically similar antigenic components were present in the extracts from the three species.

Temperature Effect on Seed Germination Performance of a Local Variety of Onion in Bangladesh

2021 ◽  
Vol 1 (01) ◽  
pp. 27-30
Author(s):  
IRANI KHATUN ◽  
RIYAD HOSSEN
Keyword(s):  
Seed Germination ◽  
Temperature Effect ◽  
Performance Test ◽  
Germination Rate ◽  
Germination Percentage ◽  
Optimum Range ◽  
Local Variety ◽  
Different Temperatures ◽  
Local Farmers

Seed germination performance test of Taherpuri onion (a local variety of onion) under six different temperatures (15, 20, 25, 30, 35 and 40°C) was the main goal of this experiment. Germination percentage (GP) was calculated at highest 60.25% at 25°C, and the highest germination rate 20.08 was observed in the same temperature condition. The lowest germination performance (13.25 % germi-nation and 3.32 seeds per day as germination rate) was found at 40°C temperature. Finally, the authors mentioned the temperature 20 to 30°C as optimum range, and suggested the temperature 25°C as best suited for obtaining highest results in case of both germination percentage and germination rate of these seeds. To produce maximum seedlings of the local variety of onion, the mentioned temperature should be followed by the local farmers.

scholarly journals New Cancer Stochastic Models Involving Both Hereditary and Nonhereditary Cancer Cases: A New Approach

2013 ◽  
Vol 2013 ◽  
pp. 1-19
Author(s):  
Wai-Yuan Tan ◽  
Hong Zhou
Keyword(s):  
Cancer Incidence ◽  
Stochastic Models ◽  
Biological Information ◽  
Cancer Genes ◽  
New Approach ◽  
Human Cancers ◽  
Seer Data ◽  
Sampling Procedures ◽  
And Control ◽  
Better Than

To incorporate biologically observed epidemics into multistage models of carcinogenesis, in this paper we have developed new stochastic models for human cancers. We have further incorporated genetic segregation of cancer genes into these models to derive generalized mixture models for cancer incidence. Based on these models we have developed a generalized Bayesian approach to estimate the parameters and to predict cancer incidence via Gibbs sampling procedures. We have applied these models to fit and analyze the SEER data of human eye cancers from NCI/NIH. Our results indicate that the models not only provide a logical avenue to incorporate biological information but also fit the data much better than other models. These models would not only provide more insights into human cancers but also would provide useful guidance for its prevention and control and for prediction of future cancer cases.

Field assessment of partial resistance to mycosphaerella blight in Pisum subspecies accessions

2012 ◽  
Vol 92 (2) ◽  
pp. 289-296 ◽  
Author(s):  
R. L. Conner ◽  
B. D. Gossen ◽  
S. F. Hwang ◽  
K. F. Chang ◽  
K. B. McRae ◽  
...  
Keyword(s):  
Partial Resistance ◽  
Field Trials ◽  
Field Pea ◽  
Mycosphaerella Pinodes ◽  
Detached Leaf ◽  
High Severity ◽  
Field Assessment ◽  
Ascochyta Pinodes ◽  
The Mean ◽  
Production Areas

Conner, R. L., Gossen, B. D., Hwang, S. F., Chang, K. F., McRae, K. B. and Penner, W. C. 2012. Field assessment of partial resistance to mycosphaerella blight in Pisum subspecies accessions. Can. J. Plant Sci. 92: 289–296. Mycosphaerella blight, caused by Mycosphaerella pinodes (Berk. & Bloxam) Vestergr., the teleomorph of Ascochyta pinodes Jones, is an important foliar disease of field pea in the major production areas of the world. Partial resistance to mycosphaerella blight has been reported in some field pea cultivars, but, at best, they are only moderately susceptible. A 3-yr field study was conducted to evaluate the mycosphaerella blight reactions of 28 accessions from a number of subspecies of Pisum sativum L. and one accession of P. fulvum Sibth. A few of the accessions carried mutations for the genes af, tl, and st that affect the morphology of the leaflets, stipules and tendrils. Reactions to mycosphaerella blight were characterized based on the mean of the severity ratings taken on the two final assessment dates before the crop matured and also on the change in mycosphaerella blight severity between these two dates. In many of the accessions, severity ratings were similar to that of the moderately susceptible check cultivar, CDC Peko, while a few had high severity ratings similar to those of the susceptible check cultivars. The accession PI 512079, which has small stipules, branched petioles with many leaflets but no tendrils, had the lowest ratings for mycosphaerella blight severity. Four other accessions exhibited the smallest change in mycosphaerella blight severity at the end of the growing season. Differences in leaf morphology likely influenced the change in disease severity, since all the semi-leafless and leafless accessions had smaller changes in mycosphaerella blight severity than the susceptible check cultivars. In a detached leaf assay with two isolates of Mycosphaerella pinodes (Berk. & Bloxam) Vestergr., the smallest lesions formed on PI 512079, but otherwise the results failed to show a relationship with the observed severity values in the field trials.

scholarly journals THE EFFECTIVENESS OF REALISTIC MATHEMATICS EDUCATION TO IMPROVE STUDENTS’ MULTI-REPRESENTATION ABILITY

2019 ◽  
Vol 8 (1) ◽  
pp. 21 ◽  
Author(s):  
Muhtarom Muhtarom ◽  
Nizaruddin Nizaruddin ◽  
Farida Nursyahidah ◽  
Nurina Happy
Keyword(s):  
Mathematics Education ◽  
Experimental Design ◽  
Learning Process ◽  
Realistic Mathematics Education ◽  
Student Responses ◽  
Realistic Mathematics ◽  
Quasi Experimental ◽  
And Control ◽  
Essay Test ◽  
Better Than

This research aimed to evaluate the effectiveness of Realistic Mathematics Education (RME) to improve students' multi-representation ability. A quasi-experimental design was used in this research. Sixty-four samples from the seventh-grade students of Junior School were randomly selected and divided into two classes: experimental class was treated using RME and control class was treated using conventional learning, with each class consisting of thirty-two students. The essay test was used to measure the multi-representation ability of students and the questionnaire was used to measure students' responses in RME learning. The data from the essay test were analyzed by N-Gain test and t-test in which normality and homogenity test were conducted previously, while the students' learning completeness and student responses were presented descriptive quantitative. The result of the research concluded that the multi-representation ability of students who get RME learning is better than the multi-representation ability in students who get conventional learning. 87.25% of students who get RME learning with the developed device have completed the KKM, and many students are very enthusiastic and interested in RME based learning, thus increasing their learning spirit in a learning process.

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