Yield losses of soybeans due to Phytophthora megasperma f.sp. Glycinea

1989 ◽  
Vol 40 (6) ◽  
pp. 1161 ◽  
Author(s):  
MJ Ryley ◽  
HF Mosetter ◽  
JL Rose
Keyword(s):  
The United States ◽  
Field Trials ◽  
Field Resistance ◽  
Growth Stages ◽  
Yield Losses ◽  
Phytophthora Megasperma ◽  
High Death Rate ◽  
High Death ◽  
Soybean Genotypes ◽  
Seed Yields

Field trials were conducted in two seasons to determine the influence of Phytophthora megasperma f.sp. glycinea on seed yields of soybean genotypes with different levels of resistance. The fungicide metalaxyl, applied as a seed dressing and soil drenches, was used to control the disease. The cultivar Davis, which has high field resistance, did not suffer significant losses in either year. whereas the yield depression of less resistant genotypes ranged up to 72%, depending on the genotype and year. In 198 1 - 82 high death rate of plants occurred early in the season, but yield losses were less than in 1982-83 when mortality occurred late in the season. The declining ability of surviving plants to compensate for disease losses during the latter growth stages may account for the differences in yield losses between seasons.Genotypes with immunity to P. megasperma f.sp. glycinea have been widely grown in the United States because they offer complete protection against some races. However, new pathogenic races have developed quickly, and previously immune genotypes have then suffered severe yield losses. The results of these trials demonstrate that yield losses can be prevented without resorting to fungicide treatments. It is likely that a stable long-term solution to phytophthora root and stem rot will be conferred by field resistance.

scholarly journals Effect of Fungicide and Timing of Application on Soybean Rust Severity and Yield

Plant Disease ◽  
2009 ◽  
Vol 93 (3) ◽  
pp. 243-248 ◽  
Author(s):  
T. A. Mueller ◽  
M. R. Miles ◽  
W. Morel ◽  
J. J. Marois ◽  
D. L. Wright ◽  
...  
Keyword(s):  
United States ◽  
The United States ◽  
Field Trials ◽  
Soybean Rust ◽  
Growth Stages ◽  
Yield Losses ◽  
Treatment Timing ◽  
Progress Curve ◽  
Significant Yield ◽  
Rust Severity

Soybean rust, caused by Phakopsora pachyrhizi, is a devastating foliar disease of soybean that may cause significant yield losses if not managed by well-timed fungicide applications. To determine the effect of fungicide timing on soybean rust severity and soybean yield, field trials were completed in Paraguay (four locations), the United States (two locations), and Zimbabwe (one location) from 2005 to 2006. Treatments at each location included applications of tebuconazole, pyraclostrobin, or a combination of azoxystrobin + propiconazole, and in some locations pyraclostrobin + tebuconazole at the following soybean growth stages (GS): (i) GS R1 (beginning flowering), (ii) GS R3 (beginning pod), (iii) GS R5 (beginning seed), (iv) GS R1 + R3, (v) GS R3 + R5, and (vi) GS R1 + R3 + R5. Soybean yields from plots treated with fungicides were 16 to 114% greater than yields from no fungicide control plots in four locations in Paraguay, 12 to 55% greater in two locations in the United States, and 31% greater in Zimbabwe. In all locations, rust severity measured over time as area under the disease progress curve (AUDPC) was negatively correlated (r = –0.3, P < 0.0001) to yield. The effectiveness of any given treatment (timing of application and product applied) was often dependent on when rust was first detected and the intensity of its development. For example, when soybean rust was first observed before GS R3 (two locations in Paraguay), the plants in plots treated with a fungicide at GS R1 had the lowest AUPDC values and highest yields. When soybean rust was first observed after GS R3, plants treated with a fungicide at GS R3 and/or GS R5 had the lowest AUDPC values and highest yields with a few exceptions.

Glasshouse and field screening of chickpea cultivars for resistance to Phytophthora megasperma f.sp. medicaginis

1991 ◽  
Vol 31 (5) ◽  
pp. 663 ◽  
Author(s):  
ML Dale ◽  
JAG Irwin
Keyword(s):  
Disease Incidence ◽  
Field Trials ◽  
Field Resistance ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
Progress Curve ◽  
Susceptible Control ◽  
Epidemic Development ◽  
Compound Interest ◽  
Chickpea Cultivars

The resistance expressed by a range of chickpea cultivars to phytophthora root rot in glasshouse and field trials was examined. Van der Plank's compound interest equation was the most suitable transformation for providing parameters to describe epidemic development for most of the cultivars when compared to the simple interest equation by plotting residuals and coefficients of determination. The area under the disease progress curve (AUDPC) was significantly correlated with the final disease incidence (FDI), which was also significantly correlated with the apparent infection rate (r), but r and AUDPC were not significantly correlated. The AUDPC proved to be relatively indiscriminate in this study for selecting resistant cultivars, since the value for the susceptible control cultivar was high, and many cultivars therefore had statistically lower AUDPC values. Several cultivars (i.e. CQ1591, ICC7568 and 232-4) were resistant on the basis of both the FDI and r parameters in the field trial and considered worthy of further investigation. When the parameters FDI or r were used to categorise the disease reactions of cultivars in the field, only half of the 30 cultivars assessed showed similar responses in both the glasshouse and field trials. The glasshouse assay used here does not allow the detection of all potentially useful forms of field resistance, and further work is needed in the development of a glasshouse assay which gives an accurate representation of field response to Phytophthora megasperma Drechs. f. sp. medicaginis Kuan and Erwin.

scholarly journals Soybean Genotypes Resistant to Phytophthora sojae and Compensation for Yield Losses of Susceptible Isolines

Plant Disease ◽  
1998 ◽  
Vol 82 (3) ◽  
pp. 303-306 ◽  
Author(s):  
J. R. Wilcox ◽  
S. K. St. Martin
Keyword(s):  
Seed Yield ◽  
Phytophthora Sojae ◽  
Stem Rot ◽  
Yield Losses ◽  
Yellow Seed ◽  
Soybean Cultivars ◽  
Black Seed ◽  
Soybean Genotypes ◽  
Seed Yields ◽  
Seed Coats

Two isolines, with different alleles for resistance to Phytophthora sojae, of the soybean cultivars, Beeson, Century, and Williams were grown in replicated tests to assess yield losses attributable to this pathogen. Isolines susceptible to prevalent races of the pathogen had black seed coats as a marker trait; isolines resistant to prevalent races of the pathogen had yellow seed coats. Included in the tests were blends composed of equal numbers of seed of the two isolines for each cultivar. Tests were conducted at three locations in Indiana and one location in Ohio for three years. In six environments, where Phytophthora root and stem rot damaged soybean, isolines susceptible to prevalent races of the pathogen produced seed yields from 65 to 93% of the yields of isolines resistant to these races. In four of these environments, isoline blends produced yields equal to those of the resistant isoline. In two environments, where susceptible isolines averaged 65 and 69% of the yield of the resistant isoline; the blends averaged 89 and 83% of the yield of the resistant isoline. Where the pathogen reduced yields of susceptible isolines, yellow seeds of the isoline resistant to prevalent races of the pathogen contributed from 10 to 33% more seed than would be expected if resistant and susceptible isolines contributed equally to seed yield. The data demonstrate that plants of the resistant isoline were compensating for reduced productivity of the susceptible plants in the blend.

scholarly journals Italian experiences in the management of andrological patients at the time of Coronavirus pandemic

2021 ◽  
Vol 93 (1) ◽  
pp. 111-114
Author(s):  
Carlo Maretti ◽  
Andrea Fabiani ◽  
Fulvio Colombo ◽  
Alessandro Franceschelli ◽  
Giorgio Gentile ◽  
...  
Keyword(s):  
The United States ◽  
Public Hospitals ◽  
Local Health ◽  
Global Pandemic ◽  
High Death Rate ◽  
Italian Regions ◽  
Rapid Spread ◽  
High Death ◽  
The Difference ◽  
Regional Authorities

The SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2) was first reported in December 2019, then its rapid spread around the world caused a global pandemic in March 2020 recording a high death rate. The epicenter of the victims moved from Asia to Europe and then to the United States. In this Pandemic, the different governance mechanisms adopted by local health regional authorities made the difference in terms of contagiousness and mortality together with a community strong solidarity. This document analyzes the andrological urgencies management in public hospitals and in private practice observed in Italy and in particular in the most affected Italian Regions: Emilia-Romagna and Marche.

scholarly journals Evaluation of Soybean Lines for Edamame Yield Traits and Trait Genetic Correlation

HortScience ◽  
2018 ◽  
Vol 53 (12) ◽  
pp. 1732-1736 ◽  
Author(s):  
Guo-Liang Jiang ◽  
Laban K. Rutto ◽  
Shuxin Ren
Keyword(s):  
United States ◽  
Agronomic Traits ◽  
The United States ◽  
Field Trials ◽  
Phenotypic Correlation ◽  
Genotypic Correlation ◽  
Market Demand ◽  
Breeding Lines ◽  
Fresh Biomass ◽  
Seed Yields

Edamame is a vegetable or specialty soybean (Glycine max (L.) Merr.) with high nutrition and market value. The market demand for edamame has significantly increased in the United States since its health and nutritional benefits became recognized. However, there are a limited number of domestically developed or improved edamame cultivars in the United States, and the knowledge of edamame is very limited. In this study, 86 breeding lines and cultivars of maturity group (MG) V and VI developed in the United States were evaluated in replicated field trials for edamame yield and agronomic traits in Virginia in 2015 and 2016. The results indicated that there were significant differences among the genotypes and between years in all the traits investigated (plant height, fresh biomass, pod yield, pod ratio, fresh seed yield, seed ratio, and 100-seed weights), but the yearly differences for dried 100-seed weight and dried-to-fresh ratio of seeds were insignificant. Genotype-by-year interaction effects were not significant in most cases. Estimates of the broad sense heritability varied with traits, from 23% to 88%. Coefficients of phenotypic and genotypic correlation were mostly low, but fresh pod and seed yields were highly correlated. Fresh biomass exhibited a positive phenotypic correlation with pod and seed yields, but the genotypic correlation coefficients were not significant. Twelve breeding lines were preliminarily identified to have greater edamame yield and desired traits. The information generated in this study will be helpful for edamame breeding and commercial production.

Timing and Efficacy of Fungicide Applications for Diplodia Ear Rot Management in Corn

2015 ◽  
Vol 16 (3) ◽  
pp. 123-131 ◽  
Author(s):  
Martha P. Romero Luna ◽  
Kiersten A. Wise
Keyword(s):  
Fungal Growth ◽  
The United States ◽  
Field Trials ◽  
Individual Growth ◽  
Growth Stages ◽  
Ear Rot ◽  
Management Options ◽  
Vitro Assay ◽  
Stenocarpella Maydis

Diplodia ear rot, a corn (Zea mays L.) disease caused by the fungus Stenocarpella maydis (Berk.) B. Sutton, has been a persistent ear rot across the United States. Management options are currently limited. Field trials conducted under inoculated and non-inoculated conditions were established at two locations in Indiana from 2011 to 2013 to test the fungicides azoxystrobin plus propiconazole and prothioconazole against Diplodia ear rot. Fungicides were applied at three individual growth stages during each year. Fungicides did not consistently reduce Diplodia ear rot compared to non-fungicide-treated controls in any year. Applications also did not consistently increase yield at any timing under inoculated and non-inoculated plots compared with the non-fungicidetreated control. Fungicides were tested in an in vitro assay to determine the effective fungicide concentration at which 50% of mycelial growth or conidial germination of S. maydis was inhibited (EC50). Propiconazole and prothioconazole EC50 values indicated efficacy in reducing fungal growth under controlled conditions; however, current fungicide application methods and plant barriers to fungicide contact with the pathogen may prevent these products from effectively reducing Diplodia ear rot in a field setting. Accepted for publication 23 August 2015. Published 1 September 2015

THE US HEALTHCARE SYSTEM IN THE CONTEXT OF THE PANDEMIC AND THE SOCIO-DEMOGRAPHIC CONSEQUENCES OF COVID-19

2021 ◽  
pp. 33-49
Author(s):  
Sergei Kostyaev ◽  
Keyword(s):  
Healthcare System ◽  
Death Rate ◽  
The United States ◽  
Mortality Rates ◽  
High Death Rate ◽  
The Us ◽  
The World ◽  
High Death ◽  
Coronavirus Infection ◽  
High Degree

This article is devoted to main problems of US healthcare system which resulted in one of the world highest morbidity and mortality rates caused by COVID-19 pandemic. The emphasis on outpatient treatment in recent decades and the too high degree of inequality in society have led to the fact that the country’s health system was unable to control the epidemic situation at a critical moment, which led to a high death rate from the new coronavirus infection in the United States.

Evaluation of Alternative Herbicides for Southern Crabgrass (Digitaria ciliaris) Control in St. Augustinegrass

2015 ◽  
Vol 29 (3) ◽  
pp. 536-543 ◽  
Author(s):  
Brian D. Glenn ◽  
Barry J. Brecke ◽  
J. Bryan Unruh ◽  
Jason A. Ferrell ◽  
Kevin E. Kenworthy ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Sodium Bicarbonate ◽  
Cultural Practices ◽  
Herbicide Tolerance ◽  
The United States ◽  
Field Trials ◽  
Growth Stages ◽  
Initial Application ◽  
Alternative Weed Control ◽  
Preemergence Herbicides

Southern crabgrass is a common turfgrass weed throughout the United States, and in Florida a troublesome problem in St. Augustinegrass lawns. Because of herbicide label changes and lack of herbicide tolerance, no POST herbicides are currently registered for homeowner use for crabgrass control in residential and commercial St. Augustinegrass lawns. Alternative weed control methods, including cultural practices and unconventional herbicides, have been investigated to a limited extent for postemergence crabgrass control. In this study, alternative herbicides evaluated included 30% acetic acid, borax, sodium bicarbonate, and Garden Weasel AG Crabgrass Killer (sodium bicarbonate formulation including cinnamon, wheat and corn flour, and cumin). Treatments were applied to southern crabgrass at three growth stages (one to two leaf, three to four leaf, or one to two tiller). In the greenhouse, 30% acetic acid applied twice at 280 L ha−1 and two rates of AG Crabgrass Killer at 976 or 1,465 kg ha−1 provided ≥ 70% control of one to two–leaf southern crabgrass when evaluated 7 d after initial application (DAIA). No treatment provided > 70% control of three to four–leaf or one to two–tiller southern crabgrass or any size crabgrass beyond 7 DAIA. In field trials, no treatment provided acceptable (≥ 70%) southern crabgrass control at any weed stage. Initial turf injury was unacceptable for most rates of 30% acetic acid, sodium bicarbonate, and AG Crabgrass Killer, causing > 20% St. Augustinegrass injury 7 DAIA. By 21 DAIA, turf injury levels had fallen to ≤ 20% for most treatments. Because of high turfgrass injury and little residual control, alternative herbicides tested are not an effective substitute for using preemergence herbicides for southern crabgrass control. If other options are not available, they may have a role as a limited spot treatment in St. Augustinegrass.

scholarly journals Maize Yield Response to Chemical Control of Spodoptera frugiperda at Different Plant Growth Stages in South Africa

Agriculture ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 826
Author(s):  
Johnnie van den Berg ◽  
Carmen Britz ◽  
Hannalene du Plessis
Keyword(s):  
Plant Growth ◽  
Spodoptera Frugiperda ◽  
Yield Loss ◽  
Fall Armyworm ◽  
Maize Yield ◽  
Field Trials ◽  
Yield Response ◽  
Growth Stages ◽  
Yield Losses ◽  
Plant Growth Stages

Fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae), is a major pest of maize. Yield losses between 30 and 70% in the Americas and between 11 and 100% in Africa have been reported. Little information exists on the effect of pest damage during different plant growth stages on yield loss. Previous studies showed that insecticide applications at weekly intervals did not always provide a yield gain comparable to only a single or two well-timed applications. In this study, we completed four field trials under high natural pest pressure. Treatments consisted of different regimes of insecticide applications that provided protection against damage during different growth stages. In one trial, the mean incidence of infested plants was 65%, and the yield benefit gained from four insecticide applications was 32.6%. The other three trials had 16 treatments which were divided into two spray sequences to protect plants against FAW damage for different lengths of time, between early vegetative stages and tasseling. Yield losses were 41.9, 26.5 and 56.8% for the three respective trials if no insecticides were applied. Yield loss of plants protected during earlier growth stages was significantly lower than that of the treatments which provided protection during later growth stages. More than three spray applications generally completed did not provide further yield gains. Plants that were protected more during early growth stages yield higher than plants protected during later growths stages.

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