Relationships between stripe rust severity and grain yield loss at Dooen, Victoria

1988 ◽  
Vol 39 (4) ◽  
pp. 563 ◽  
Author(s):  
JS Brown
Keyword(s):  
Grain Yield ◽  
Disease Severity ◽  
Stripe Rust ◽  
Growth Stage ◽  
Field Experiments ◽  
Yield Loss ◽  
Rust Severity ◽  
Cent Disease ◽  
The Relationship ◽  
Best Estimator

The relationship between stripe rust severity and grain yield loss in wheat was studied in two field experiments. Wheat cultivars varying in response to the disease were used to produce epidemics of differing severity. Regression models were used to examine the relationship between disease severity and yield loss. The best estimator of yield loss was an estimate of disease severity at the end of anthesis-early berry growth stage. The relationship between per cent yield loss (YL) and per cent disease severity (DS) at that growth stage was established to be YL = 0.479DS + 0.84.

Yield losses in wheat from yellow spot: comparison of estimates derived from single tillers and plots

1982 ◽  
Vol 33 (6) ◽  
pp. 899 ◽  
Author(s):  
RG Rees ◽  
GJ Platz ◽  
RJ Mayer
Keyword(s):  
Grain Yield ◽  
Disease Severity ◽  
Yield Loss ◽  
Wheat Yield ◽  
Sprinkler Irrigation ◽  
Yellow Spot ◽  
Grain Number ◽  
Pyrenophora Tritici Repentis ◽  
Wheat Stubble ◽  
The Relationship

Losses in wheat yield associated with yellow spot (Pyrenophora tritici-repentis) have been examined in a field experiment where development of crop and disease were promoted with sprinkler irrigation. Different amounts of infected wheat stubble were applied to initiate epidemics in four treatments, while fungicide sprays were used to reduce the severity of yellow spot in a fifth treatment. The relationship between severity of yellow spot and the amount of infected stubble at first appeared to be linear but became more noticeably logarithmic as the epidemics progressed. Under conditions favouring disease development, a loss in grain yield of c. 49% was measured in the most severely diseased treatment relative to the sprayed treatment, with grain number per unit area and grain size both being reduced. The percentage loss in grain yield was less for main stems than for later heads. Regression analyses of disease severity with grain yield and its components using 50 main stems in each plot gave different estimates of yield loss, depending on the growth stage at which disease severity was assessed. These estimates of yield loss and those provided by a previously developed disease-loss relationship severely underestimated the overall loss in grain yield. However, there was better agreement between estimates derived from the regressions and loss in grain yield on main stems. Possible reasons for the discrepancies in estimates of loss in grain yield are discussed.

scholarly journals EFFECT OF BOTANICALS FOR MANAGEMENT OF LEAF BLAST AND ENHANCING YIELD TRAITS IN RICE

2018 ◽  
pp. 17-21
Author(s):  
SANDEEP PANDEY
Keyword(s):  
Grain Yield ◽  
Disease Severity ◽  
Field Experiments ◽  
Disease Incidence ◽  
Grain Weight ◽  
Panicle Length ◽  
Leaf Blast ◽  
Yield Attributes ◽  
Pooled Data ◽  
Cent Disease

Field experiments were undertaken during kharif 2012 and 2013 under irrigated ecosystem to evaluate the efficacy of botanicals along with standard fungicides for assessing per cent disease incidence, plant height, number of tiller per plant, number of spikelet per panicle, panicle length, 100-grain weight and grain yield against blast of rice. Pooled data of two years suggest that neem based commercial biopesticides with azadiractin as active ingredients were found effective in reducing disease severity and improving the yield attribute of the crop and proves promising products when compared to standard fungicides. Among the botanicals the spraying of Achook, Neem Azal T/S, Neem gold and Tricure shows significant reduction in disease severity, along with improving yield attributes, increasing the 100-grain weight and grain yield.

scholarly journals The impact of cultivar resistance and fungicide treatment on mycotoxin content in grain and yield losses caused by Fusarium head blight in wheat

2010 ◽  
Vol 46 (No. 1) ◽  
pp. 21-26 ◽  
Author(s):  
V. Šíp ◽  
J. Chrpová ◽  
O. Veškrna ◽  
L. Bobková
Keyword(s):  
Grain Yield ◽  
Fusarium Head Blight ◽  
Field Experiments ◽  
Yield Loss ◽  
Joint Effect ◽  
Yield Losses ◽  
Cultivar Resistance ◽  
Head Blight ◽  
Fungicide Treatment ◽  
The Impact

Reactions to artificial infection with Fusarium graminearum isolates and a new fungicide Swing Top were studied in nine winter wheat cultivars evaluated in field experiments at two sites for three years for expression of symptoms, deoxynivalenol (DON) content in grain and grain yield. The results demonstrate a pronounced and relatively stable effect of cultivar resistance on reducing head blight, grain yield losses and contamination of grain by the mycotoxin DON. It is advantageous that the moderate level of resistance to Fusarium head blight (FHB) was detected also in two commonly grown Czech cultivars Sakura and Simila. Average fungicide efficacy for DON was 49.5% and 63.9% for a reduction in yield loss, however, it was found highly variable in different years and sites. The joint effect of cultivar resistance and fungicide treatment was 86.5% for DON and even 95.4% for reducing the yield loss. A very high risk was documented for susceptible cultivars and also the effects of medium responsive cultivars were found to be highly variable in different environments and therefore not guaranteeing sufficient protection against FHB under different conditions.

scholarly journals Management of stripe rust of barley (Hordeum vulgare L.) using fungicides

2015 ◽  
Vol 7 (1) ◽  
pp. 170-174
Author(s):  
Rakesh Devlash ◽  
Naval Kishore ◽  
Guru Dev Singh
Keyword(s):  
Hordeum Vulgare ◽  
Disease Severity ◽  
Stripe Rust ◽  
Puccinia Striiformis ◽  
Field Conditions ◽  
Hordeum Vulgare L ◽  
Grain Yields ◽  
Untreated Check ◽  
Rust Severity ◽  
Barley Stripe Rust

Under field conditions, various fungicide molecules were validated for their effectiveness on barley (Hordeum vulgare L.) stripe rust Puccinia striiformis f. sp. consecutively for three years under artificial field epiphytotic conditions. Seven fungicides viz., propiconazole 25%EC (tilt @ 0.1%), tebuconazole 25.9% m/m EC (folicur @ 0.1%), triademefon 25%WP (bayleton @ 0.1%), propiconazole 25%EC (tilt @ 0.05%), tebuconazole 25.9% m/m EC (folicur @ 0.05%), triademefon 25%WP (bayleton@ 0.05%), and mancozeb 75%WP (dithane M45 @ 0.2%) with variousconcentrations were tested for their effectiveness in controlling barley stripe rust severity. All fungicide applications resulted in lower disease severity and higher grain yields than untreated check plots. All the fungicides @ 0.1% concentrations reduced disease severity ranging from 87.8% to 95.6% except Mancozeb @ 0.2% (34.4%). Significant higher yield was obtained with Propiconazole @ 0.1% (26.7 q/ha) followed by Tebuconazole @ 0.1% (25.2 q/ha) and Triademefon @ 0.1% (24.5 q/ha). The present study revealed propiconazole as the most effective fungicide for the control of stripe rust of barley under epiphytotic conditions.

The critical weed-free period in glyphosate-resistant soybean in Ontario is similar to previous estimates using glyphosate-susceptible soybean

2019 ◽  
Vol 99 (4) ◽  
pp. 437-443
Author(s):  
Nader Soltani ◽  
Robert E. Nurse ◽  
Amit J. Jhala ◽  
Peter H. Sikkema
Keyword(s):  
Growth Stage ◽  
Field Experiments ◽  
Yield Loss ◽  
Growth Stages ◽  
Weed Species ◽  
Weed Biomass ◽  
Weed Density ◽  
Weed Interference ◽  
Beginning Of Flowering ◽  
Minimal Reduction

A study consisting of 13 field experiments was conducted during 2014–2016 in southwestern Ontario and southcentral Nebraska (Clay Center) to determine the effect of late-emerging weeds on the yield of glyphosate-resistant soybean. Soybean was maintained weed-free with glyphosate (900 g ae ha−1) up to the VC (cotyledon), V1 (first trifoliate), V2 (second trifoliate), V3 (third trifoliate), V4 (fourth trifoliate), and R1 (beginning of flowering) growth stages, after which weeds were allowed to naturally infest the soybean plots. The total weed density was reduced to 24%, 63%, 67%, 72%, 76%, and 92% in Environment 1 (Exeter, Harrow, and Ridgetown) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 soybean growth stages, respectively. The total weed biomass was reduced by 33%, 82%, 95%, 97%, 97%, and 100% in Environment 1 (Exeter, Harrow, and Ridgetown) and 28%, 100%, 100%, 100%, 100%, and 100% in Environment 2 (Clay Center) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 stages, respectively. The critical weed-free periods for a 2.5%, 5%, and 10% yield loss in soybean were the V1–V2, VC–V1, and VC–V1 soybean stages in Environment 1 (Exeter, Harrow, and Ridgetown) and V2–V3, V2–V3, and V1–V2 soybean stages in Environment 2 (Clay Center), respectively. For the weed species evaluated, there was a minimal reduction in weed biomass (5% or less) when soybean was maintained weed-free beyond the V3 soybean growth stage. These results shows that soybean must be maintained weed-free up to the V3 growth stage to minimize yield loss due to weed interference.

Inoculum pressure and the development of stem rust epidemics in barley

1991 ◽  
Vol 42 (5) ◽  
pp. 769 ◽  
Author(s):  
R Dill-Macky ◽  
RG Rees ◽  
GJ Platz
Keyword(s):  
Grain Yield ◽  
Field Experiments ◽  
Initial Inoculum ◽  
Barley Cultivars ◽  
Yield And Quality ◽  
Rust Severity ◽  
Grain Yield And Quality ◽  
Moderately Resistant ◽  
Different Levels ◽  
Inoculum Pressure

The effects of inoculum pressure on the development of epidemics of Puccinia graminis tritici in two barley cultivars with different levels of resistance were examined in two field experiments. Treatments were established by inoculation of foci within plots and/or the strategic use of fungicides. Additional 'rust-free' treatments were maintained to provide comparisons of grain yield and quality. Relationships between rust severity, rust incidence and grain yield and quality were also examined. Initial inoculum levels were important in determining disease severity and incidence for individual epidemics; however, severe epidemics developed under most 'rusted' treatments of the susceptible cultivar Galleon and reduced grain yield by up to 58%. Epidemics under corresponding treatments of the moderately resistant cultivar Grimmett were less severe, and the value of the resistance was evident with yield losses not exceeding 12%. Yield reductions were usually associated with reduced grain size and weight.

scholarly journals Velocity of Spread of Wheat Stripe Rust Epidemics

2005 ◽  
Vol 95 (9) ◽  
pp. 972-982 ◽  
Author(s):  
Christina Cowger ◽  
LaRae D. Wallace ◽  
Christopher C. Mundt
Keyword(s):  
Disease Severity ◽  
Stripe Rust ◽  
Field Experiments ◽  
Average Rate ◽  
Spatial Scales ◽  
Management Strategies ◽  
Plant Diseases ◽  
Pure Stand ◽  
Wheat Stripe Rust ◽  
Competing Models

Controversy has long existed over whether plant disease epidemics spread with constant or with increasing velocity. We conducted largescale field experiments with wheat stripe rust at Madras and Hermiston, Oregon, where natural stripe rust epidemics were rare, to test these competing models. Data from three location-years were available for analysis. A susceptible winter wheat cultivar was planted in pure stand and also in a 1:4 or 1:1 mixture with a cultivar immune to the stripe rust race utilized in the experiments. Plots were 6.1 m wide and varied from 73 to 171 m in length. A 1.5 by 1.5-m focus was inoculated in either the center (2001) or upwind of the center (2002 and 2003) of each plot. Disease severity was evaluated weekly throughout the epidemics in each plot at the same points along a transect running upwind and downwind from the focus. Velocity of spread was calculated from the severity data and regressed separately on time and on distance from the focus. In all location-years and treatments, and at all levels of disease severity, velocity consistently increased linearly with distance, at an average rate of 0.59 m/week per m, and exponentially with time. Further, across epidemics there was a significant positive relationship between the apparent infection rate, r, and the rate of velocity increase in both space and time. These findings have important implications for plant diseases with a focal or partially focal character, and in particular for the effectiveness of ratereducing disease management strategies at different spatial scales.

scholarly journals Relationships Between Early Wheat Streak Mosaic Severity Levels and Grain Yield: Implications for Management Decisions

Plant Disease ◽  
2017 ◽  
Vol 101 (9) ◽  
pp. 1621-1626 ◽  
Author(s):  
F. Workneh ◽  
S. O’Shaughnessy ◽  
S. Evett ◽  
C. M. Rush
Keyword(s):  
Grain Yield ◽  
Disease Severity ◽  
Water Conservation ◽  
Field Experiments ◽  
Regression Function ◽  
High Plains ◽  
Management Decisions ◽  
Texas High Plains ◽  
Severity Levels ◽  
The Impact

Wheat streak mosaic (WSM) caused by Wheat streak mosaic virus, which is transmitted by the wheat curl mite (Aceria tosichella), is a major yield-limiting disease in the Texas High Plains. In addition to its impact on grain production, the disease reduces water-use efficiency by affecting root development. Because of the declining Ogallala Aquifer water level, water conservation has become one of the major pressing issues in the region. Thus, questions are often raised as to whether it is worthwhile to irrigate infected fields in light of the water conservation issues, associated energy costs, and current wheat prices. To address some of these questions, field experiments were conducted in 2013 and 2016 at two separate locations to determine whether grain yield could be predicted from disease severity levels, assessed early in the spring, for potential use as a decision tool for crop management, including irrigation. In both fields, disease severity assessments started in April, using a handheld hyperspectral radiometer with which reflectance measurements were taken weekly in multiple plots in arbitrarily selected locations across the fields. The relationship between WSM severity levels and grain yield for the different assessment dates were determined by fitting reflectance and yield values into the logistic regression function. The model predicted yield levels with r2 values ranging from 0.67 to 0.85 (P < 0.0001), indicating that the impact of WSM on grain yield could be fairly well predicted from early assessments of WSM severity levels. As the disease is normally progressive over time, this type of information will be useful for making management decisions of whether to continue irrigating infected fields, especially if combined with an economic threshold for WSM severity levels.

An analysis of yield reduction caused by stripe rust in Rongotea wheat.

1991 ◽  
Vol 42 (1) ◽  
pp. 45 ◽  
Author(s):  
RE Gaunt ◽  
MJ Cole
Keyword(s):  
Disease Severity ◽  
Stripe Rust ◽  
Yield Components ◽  
Seed Treatment ◽  
Disease Duration ◽  
Puccinia Striiformis ◽  
Empirical Models ◽  
Yield Reduction ◽  
The Relationship ◽  
Action Levels

Natural field epidemics of stripe rust (Puccinia striiformis) were manipulated by seed treatment and foliar sprays to provide a range of disease severities and durations in several locations in three seasons. Yield in the absence of disease, disease severity and disease duration in the natural epidemics varied markedly between the three seasons. The effect of disease on yield and yield components was different in each season and there was no empirical model which consistently described the relationship between disease severity and yield reduction. Empirical models had little relation to the cause of yield reduction in specific crops and could not therefore be used for disease management purposes. The identification of action levels for management purposes based on mechanistic criteria is discussed.

Effects of hybrid susceptibility and inoculation timing on Goss’s bacterial wilt and leaf blight severity and corn yield

Plant Disease ◽  
2021 ◽  
Author(s):  
Elizabeth C Bauske ◽  
Andrew J Friskop
Keyword(s):  
Disease Severity ◽  
Bacterial Wilt ◽  
Field Experiments ◽  
Yield Loss ◽  
Leaf Blight ◽  
Corn Yield ◽  
Yield Losses ◽  
Sequential Combination ◽  
High Level ◽  
Growing Region

Goss’s bacterial wilt and leaf blight (Goss’s wilt) of corn is the most important corn disease in North Dakota (ND), and yield loss due to the disease has not been reliably quantified in northern corn growing regions. To help quantify the amount of yield loss caused by Goss’s wilt, a total of six field experiments were conducted from 2015 to 2017. Experiments were designed in a randomized complete block with a split plot arrangement. Hybrids served as main plots and Clavibacter nebraskensis (Cn) inoculation timings as sub-plots. Three hybrids were used and classified as a susceptible, moderately susceptible, and resistant. Inoculation timings included a non-inoculated control, six to ten leaf collars (V6 to V10), reproductive silk stage (R1), or a sequential combination of V6 to V10 and R1. A high level of disease (greater than 50% on susceptible hybrid) occurred in three experiments, a low level of disease (less than 5% on susceptible hybrid) in one experiment, and no disease was reported in two experiments. A combined analysis of the high disease experiments indicated yield losses of 34 to 41% on the susceptible hybrid when Cn inoculation occurred at V6 to V10. Yield losses of 22 to 25% occurred on the moderately susceptible hybrid when C. nebraskensis inoculation occurred at V6 to V10, and statistical differences in yield loss were not found among inoculations timings on the resistant hybrid. Correlation analyses suggest that for every 1% increase in R1 disease severity on the susceptible hybrid, yield was reduced by 117 kg/ha (1.9 bu/A). The current study further demonstrates the importance of hybrid resistance and provides updated yield loss information on Goss’s wilt in a northern corn growing region.

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