Evaluation of Sequential Fungicide Spray Programs for Control of Soybean Rust

Soybean rust (SBR), caused by the fungus Phakopsora pachyrhiza, has been a recurring problem for soybean growers in the southern United States. In some cases, growers in this region have followed a fungicide spray program consisting of two fungicide applications to protect their crop from the disease. Our study was conducted to determine how various sequential fungicide spray programs perform under the relatively high SBR pressure found in Alabama. Results from this study suggest that there are significant differences in the relative effectiveness of a program based on products used and the sequence in which they are applied. Factors such as recent weather conditions, proximity to sources of SBR, cost of available products, and an estimate of a crops yield potential should be considered when choosing a fungicide program. Accepted for publication 10 February 2009. Published 2 April 2009.

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Suppression of Soybean Yield Potential in the Continental United States by Plant Diseases from 2006 to 2009

Plant Health Progress ◽

10.1094/php-2010-1122-01-rs ◽

2010 ◽

Vol 11 (1) ◽

pp. 5 ◽

Cited By ~ 138

Author(s):

Stephen R. Koenning ◽

J. Allen Wrather

Keyword(s):

United States ◽

The United States ◽

Plant Diseases ◽

Soybean Rust ◽

Yield Potential ◽

Stem Rot ◽

Yield Losses ◽

Sclerotinia Stem Rot ◽

Soybean Yield ◽

The Impact

Research must focus on management of diseases that cause extensive losses, especially when funds for research are limited. Knowledge of the losses caused by various soybean diseases is essential when prioritizing research budgets. The objective of this project was to compile estimates of soybean yield potential losses caused by diseases for each soybean producing state in the United States from 2006 to 2009. This data is of special interest since the 4-year period summarized in this report, permits an examination of the impact of soybean rust that was first reported in the United States in 2004. Thus, in addition to the goal of providing this information to aid funding agencies and scientists in prioritizing research objectives and budgets, an examination of the impact of soybean rust on soybean yield losses relative to other diseases is warranted. Yield losses caused by individual diseases varied among states and years. Soybean cyst nematode caused more yield losses than any other disease during 2006 to 2009. Seedling diseases, Phytophthora root and stem rot, sudden death syndrome, Sclerotinia stem rot, and charcoal rot ranked in the top six of diseases that caused yield loss during these years. Soybean yield losses due to soybean rust and Sclerotinia stem rot varied greatly over years, especially when compared to other diseases. Accepted for publication 21 October 2010. Published 22 November 2010.

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New Legume Hosts of Phakopsora pachyrhizi Based on Greenhouse Evaluations

Plant Disease ◽

10.1094/pdis-92-5-0767 ◽

2008 ◽

Vol 92 (5) ◽

pp. 767-771 ◽

Cited By ~ 31

Author(s):

T. L. Slaminko ◽

M. R. Miles ◽

R. D. Frederick ◽

M. R. Bonde ◽

G. L. Hartman

Keyword(s):

United States ◽

New Species ◽

The United States ◽

Soybean Rust ◽

Southern United States ◽

Phakopsora Pachyrhizi ◽

Legume Species ◽

Causal Organism ◽

Immunological Assay ◽

Phaseolus Species

Phakopsora pachyrhizi, the causal organism of soybean rust, was first found in the continental United States in 2004 and has been found on soybean, kudzu, Florida beggarweed, and three Phaseolus species in the field. The pathogen has been reported to occur on more than 90 legume species worldwide and it is likely to infect native and introduced legume species in the United States. The objective of this study was to determine if 176 species representing 57 genera of legumes, the majority of which are either native or naturalized to soybean-growing areas of the United States, could be hosts of P. pachyrhizi. Between one and three accessions of each species, a total of 264 accessions, were inoculated with a mixture of four isolates of P. pachyrhizi. Severity and sporulation were rated on a 1-to-5 scale at 14 and 28 days after inoculation. P. pachyrhizi was confirmed by the presence of sporulating uredinia and/or immunological assay on 65 new species in 25 genera; 12 of these genera have not been reported previously as hosts. Many of the newly identified hosts grow in the southern United States, and like kudzu, could serve as overwintering hosts for P. pachyrhizi.

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First Report of Soybean Rust Caused by Phakopsora pachyrhizi on Kudzu (Pueraria montana var. lobata) in Illinois

Plant Disease ◽

10.1094/pdis-94-4-0477a ◽

2010 ◽

Vol 94 (4) ◽

pp. 477-477 ◽

Cited By ~ 1

Author(s):

C. A. Bradley ◽

R. A. Hines ◽

N. R. Pataky ◽

J. S. Haudenshield ◽

G. L. Hartman

Keyword(s):

United States ◽

The State ◽

The Other ◽

Soybean Rust ◽

Southern United States ◽

Phakopsora Pachyrhizi ◽

Southern Illinois ◽

Glycine Max L ◽

Health Progress ◽

Pueraria Montana

Soybean rust, caused by Phakopsora pachyrhizi Syd., first was observed in the continental United States during 2004 on soybean (Glycine max (L.) Merr.) in Louisiana (4), and on kudzu (Pueraria montana (Lour.) Merr. var. lobata (Willd.) Maesen & Almeida) in Florida (2). Kudzu is a leguminous weed that is prevalent in the southern United States with its range extending northward into other states including Illinois. In October 2009, a kudzu patch located in Pulaski County in southern Illinois was investigated for the presence of soybean rust. Twenty-five leaflets were collected, and the abaxial sides of leaflets were evaluated visually for the presence of uredinia with a dissecting microscope. Uredinia and urediniospores were found on two leaflets. When viewed with a compound microscope, urediniospores were hyaline, echinulate, and measured 20 × 25 μm. On the basis of uredinia and urediniospores, the disease tentatively was identified as soybean rust caused by P. pachyrhizi. To confirm the identification, one leaflet with pustules was assayed with a Soybean Rust QuickStix Diagnostic Kit (Envirologix, Portland, ME). For the other leaflet, the area of the pustule was excised (approximately 28 mm2) and an area of the leaflet at the margin on the opposite half of the leaflet with no visible pustule (approximately 54 mm2) was excised. DNA was extracted from the excised areas of the leaflet for confirmation by quantitative PCR (Q-PCR) using primers and probe specific to P. pachyrhizi and P. meibomiae (Arthur) Arthur (1). Both the QuickStix Diagnostic Kit and the Q-PCR confirmed the diagnosis as soybean rust caused by P. pachyrhizi. Q-PCR also suggested the presence of a nonsporulating latent rust infection on the same kudzu leaflet at the margin on the opposite side of the midrib. Soybean rust first was confirmed on soybean in Illinois in 2006 (3), but to our knowledge, this is the first observation of the disease on kudzu in the state. This report confirms that at least some kudzu plants in Illinois are susceptible to soybean rust and that latent kudzu infection may exist without outward signs of the fungus. Currently, this is the most northern observation of soybean rust on kudzu in North America. It is unknown what role, if any, Illinois kudzu will play in the epidemiology of soybean rust in the state. Since kudzu tops die after the first frost, there is no expectation of P. pachyrhizi to overwinter in Illinois on kudzu as it does in some states adjacent to the Gulf of Mexico. References: (1) R. D. Frederick et al. Phytopathology 92:217, 2002. (2) P. F. Harmon et al. Online publication. doi:10.1094/PHP-2005-0613-01-RS. Plant Health Progress, 2005. (3) G. L. Hartman et al. Plant Dis. 91:466, 2007. (4) R. W. Schneider et al. Plant Dis. 89:774, 2005.

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035 A New Southernpea

HortScience ◽

10.21273/hortsci.34.3.447b ◽

1999 ◽

Vol 34 (3) ◽

pp. 447B-447 ◽

Cited By ~ 1

Author(s):

T.E. Morelock ◽

D.R. Motes ◽

A.R. Gonzalez

Keyword(s):

United States ◽

Yield Potential ◽

Southern United States ◽

Medium Size ◽

Fresh Market ◽

Bright Pink ◽

Early Maturing ◽

Important Processing ◽

High Yielding Varieties

Southernpea (cowpea), Vigna ungiculata L. Walp, is an important processing and fresh-market vegetable in the southern United States. While many of the newer varieties are early maturing, there is still a need for late-maturing, high-yielding varieties. Arkansas 92-552 fills this niche. It is a bush plant that produces silver pods in the upper portion of large plants that are free of basal runners. The seed are medium size with a bright pink eye. Maturity is 5 to 7 days later than `Coronet' under Arkansas conditions. The variety processes well and canned peas have been rated equal to `Coronet' by consumers panels. The yield potential is high and it has produced higher yield than `Coronet' in replicated trials in Arkansas. 92-552 is also resistant to rootknot nematode.

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Post-hurricane forest management responses in the southern United States

Journal of Emergency Management ◽

10.5055/jem.2009.0038 ◽

2009 ◽

Vol 7 (6) ◽

pp. 35

Author(s):

Pete Bettinger, PhD ◽

Krista L. Merry, MS ◽

Jeffrey Hepinstall, PhD

Keyword(s):

United States ◽

Forest Management ◽

Forest Health ◽

Storm Surges ◽

Weather Conditions ◽

The United States ◽

Southern United States ◽

Service Needs ◽

Strong Winds ◽

Social Recovery

Although people living along the southeastern and Gulf coasts of the United States may have limited experience dealing with major hurricane damage, hurricanes are imminent and pose potentially dire consequences to forest resources. In addition to understanding the physical and biological reactions of forests to extreme weather conditions, there are a number of managerial responses that should be considered based on this past experience. This article presents a summary of the more pertinent forest management responses, and where appropriate, highlights situations where these were beneficial to the overall (economic, ecological, social) recovery effort. Management responses address not only the immediate needs for clearing roads and restoring basic service needs, but also the longer-term issues related to timber salvage, reforestation, forest health, and fire danger. The damage from strong winds and storm surges may also result in serious consequences for ecological values. However, challenges and issues related to the restoration of forests and forest-related values may require several years to address. Therefore, the objective of this review article is to provide a summary of the experiences of forest land managers, researchers, and emergency planners who have directly responded to severe storms affecting the southern United States.

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Evaluation of USDA Soybean Germplasm Accessions for Resistance to Soybean Rust in the Southern United States

Crop Science ◽

10.2135/cropsci2010.06.0340 ◽

2011 ◽

Vol 51 (2) ◽

pp. 678-693 ◽

Cited By ~ 28

Author(s):

D. R. Walker ◽

H. R. Boerma ◽

D. V. Phillips ◽

R. W. Schneider ◽

J. B. Buckley ◽

...

Keyword(s):

United States ◽

Soybean Rust ◽

Southern United States ◽

Soybean Germplasm ◽

Germplasm Accessions

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Relating Epidemic Progress from a General Disease Model to Seasonal Appearance Time of Rusts in the United States: Implications for Soybean Rust

Phytopathology ◽

10.1094/phyto-96-0400 ◽

2006 ◽

Vol 96 (4) ◽

pp. 400-407 ◽

Cited By ~ 26

Author(s):

Shimon Pivonia ◽

X. B. Yang

Keyword(s):

United States ◽

Disease Model ◽

Weather Conditions ◽

The United States ◽

Soybean Rust ◽

Long Distance ◽

Appearance Time ◽

Comparative Epidemiology ◽

Lag Period ◽

The U.S

Soybean rust, Phakopsora pachyrhizi, has been considered a threat to the production of the U.S. soybean, Glycine max. During the past decade, this disease gradually spread to Africa, South America, and recently to the United States. Previous soybean rust risk assessments with an assumption of availability of spores early in a season showed that weather conditions (dew and temperature) during a growing season, in general, are suitable for disease development in U.S. soybean-growing regions. Predicting the time of rust appearance in a field is critical to determining the destructive potential of rusts, including soybean rust. In this study, comparative epidemiology was used to assess likely rust incipient time in four locations within the U.S. Soybean Belt from south to north: Baton Rouge, LA; Charlotte, NC; Indianapolis, IN; and Minneapolis, MN. Temperature effects on the infection cycle of five rusts occurring in the Midwest were evaluated using a general disease model. The likely incipient times were examined with the modeling results. Among the rusts studied, early-appearing rusts had suitable conditions for development earlier in a season. However, a lag period of several weeks to more than 3 months was found from the time when conditions are suitable for a rust to develop or when hosts are available to the time when the rust was detected in fields. Length of the lag period differed among the rust species examined. If nature of long-distance dispersal is not significantly different among the rusts, implications of our study to the expected seasonal soybean rust incipience in fields lead to two possible scenarios: (i) average appearance time of soybean rust across the Soybean Belt should be somewhere between appearance times of common corn rust and southern corn rust, and (ii) with late appearance of the disease, late-planted soybean in the south has greater risk.

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QTL and major genes influencing grain yield potential in soft red winter wheat adapted to the southern United States

Euphytica ◽

10.1007/s10681-016-1650-1 ◽

2016 ◽

Vol 209 (3) ◽

pp. 665-677 ◽

Cited By ~ 10

Author(s):

Christopher K. Addison ◽

R. Esten Mason ◽

Gina Brown-Guedira ◽

Mohammed Guedira ◽

Yuanfeng Hao ◽

...

Keyword(s):

United States ◽

Winter Wheat ◽

Grain Yield ◽

Yield Potential ◽

Southern United States ◽

Major Genes ◽

Soft Red Winter Wheat ◽

Red Winter Wheat

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Modifying the NRC weight gain model to estimate daily gain for stockers grazing bermudagrass in the southern United States

Journal of Animal Science ◽

10.1093/jas/skac011 ◽

2022 ◽

Author(s):

Prem Woli ◽

Francis M Rouquette ◽

Charles R Long ◽

Luis O Tedeschi ◽

Guillermo Scaglia

Keyword(s):

United States ◽

Weight Gain ◽

Weather Conditions ◽

Southern United States ◽

Animal Performance ◽

Grazing Season ◽

Daily Weather ◽

Daily Weather Data ◽

Nutritive Values ◽

Daily Gain

Abstract The energy requirements, feed intake, and performance of grazing animals vary daily due to changes in weather conditions, forage nutritive values, and plant and animal maturity throughout the grazing season. Hence, realistic simulations of daily animal performance can be made only by the models that can address these changes. Given the dearth of simple, user-friendly models of this kind, especially for pastures, we developed a daily gain model for large-frame stockers grazing bermudagrass [Cynodon dactylon (L.) Pers.], a widely-used warm-season perennial grass in the southern United States. For model development, we first assembled some of the classic works in forage-beef modeling in the last 50 years into the National Research Council (NRC, 1984) weight gain model. Then, we tested it using the average daily gain (ADG) data obtained from several locations in the southern United States. The evaluation results showed that the performance of the NRC model was poor as it consistently underpredicted ADG throughout the grazing season. To improve the predictive accuracy of the NRC model to make it perform under bermudagrass grazing conditions, we made an adjustment on the model by adding the daily departures of the modeled values from the data trendline. Subsequently, we tested the revised model against an independent set of ADG data obtained from eight research locations in the region involving about 4,800 animals, using 30 years (1991-2020) of daily weather data. The values of the various measures of fit used, namely the Willmott index of 0.92, the modeling efficiency of 0.75, the R 2 of 0.76, the root mean square error of 0.13 kg d -1, and the prediction error relative to the mean observed data of 24% demonstrated that the revised model mimicked the pattern of observed ADG data satisfactorily. Unlike the original model, the revised model predicted more closely the ADG value throughout the grazing season. The revised model may be useful to accurately reflect the impacts of daily weather conditions, forage nutritive values, seasonality, and plant and animal maturity on animal performance.

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