Documentation of an Extended Latent Infection Period by <i>Phakopsora pachyrhizi</i>, the Soybean Rust Pathogen

Ward, N. A.; Schneider, R. W.; Robertson, C. L.

doi:10.1094/php-2012-0321-01-rs

Cited by 3 publications

(1 citation statement)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another concern that complicates fungicide application timing is the fact that P. pachyrhizi may, under some circumstances, have an extended latent period (up to 60 days) that would complicate the timing and use of curative and protective fungicides (Schneider et al 2009b;Ward et al 2012). In summary, both host resistance and fungicide applications are major components to an integrated management strategy but there may be other considerations that may influence the severity of a rust epidemic, including planting dates and cultivar maturity.…”

Section: Soybean Rust Managementmentioning

confidence: 99%

From Select Agent to an Established Pathogen: The Response to Phakopsora pachyrhizi (Soybean Rust) in North America

et al. 2015

View full text Add to dashboard Cite

The pathogen causing soybean rust, Phakopsora pachyrhizi, was first described in Japan in 1902. The disease was important in the Eastern Hemisphere for many decades before the fungus was reported in Hawaii in 1994, which was followed by reports from countries in Africa and South America. In 2004, P. pachyrhizi was confirmed in Louisiana, making it the first report in the continental United States. Based on yield losses from countries in Asia, Africa, and South America, it was clear that this pathogen could have a major economic impact on the yield of 30 million ha of soybean in the United States. The response by agencies within the United States Department of Agriculture, industry, soybean check-off boards, and universities was immediate and complex. The impacts of some of these activities are detailed in this review. The net result has been that the once dreaded disease, which caused substantial losses in other parts of the world, is now better understood and effectively managed in the United States. The disease continues to be monitored yearly for changes in spatial and temporal distribution so that soybean growers can continue to benefit by knowing where soybean rust is occurring during the growing season.

show abstract

Section: Soybean Rust Managementmentioning

confidence: 99%

From Select Agent to an Established Pathogen: The Response to Phakopsora pachyrhizi (Soybean Rust) in North America

et al. 2015

View full text Add to dashboard Cite

show abstract

Development of a Quantitative Polymerase Chain Reaction Detection Protocol for Cercospora kikuchii in Soybean Leaves and Its Use for Documenting Latent Infection as Affected by Fungicide Applications

Chanda¹,

Ward

Robertson

et al. 2014

Phytopathology®

View full text Add to dashboard Cite

Cercospora leaf blight (CLB) of soybean, caused by Cercospora kikuchii, is a serious disease in the southern United States. A sensitive TaqMan probe-based real-time quantitative polymerase chain reaction (qPCR) assay was developed to specifically detect and quantify C. kikuchii in naturally infected soybean plants. The sensitivity was 1 pg of genomic DNA, which was equivalent to about 34 copies of genome of C. kikuchii. Using this qPCR assay, we documented a very long latent infection period for C. kikuchii in soybean leaves beginning at the V3 growth stage (as early as 22 days after planting). The levels of biomass of C. kikuchii remained low until R1, and a rapid increase was detected from the R2/R3 to R4/R5 growth stages shortly before the appearance of symptoms at R6. The efficacy of various fungicide regimens under field conditions also was evaluated over a 3-year period using this qPCR method. Our results showed that multiple fungicide applications beginning at R1 until late reproductive stages suppressed the development of C. kikuchii in leaves and delayed symptom expression. Different fungicide chemistries also had differential effects on the amount of latent infection and symptom expression during late reproductive growth stages.

show abstract

Effects of Frequency of “Extreme” Temperature Highs on Development of Soybean Rust

Bonde

Nester²,

Berner³

2013

Phytopathology®

View full text Add to dashboard Cite

Previously, we hypothesized that summer "extreme" diurnal temperature highs in the southeastern United States were responsible for the yearly absence or delay of soybean rust development until fall. Utilizing temperature-controlled growth chambers, a diurnal temperature pattern of 33°C high and 20°C low reduced urediniospore production by 81%. However, that study did not consider the influence of frequency of extreme temperatures on soybean rust. We now report that a temperature high of 35°C for 1 h on three consecutive days, initiated 15 days after inoculation, when lesions had formed, reduced urediniospore production by 50% and required 9 to 12 days for sporulation to resume once the extreme temperature highs ceased. Furthermore, three consecutive days in which the temperature high was 37°C, beginning immediately after inoculation and subsequent dew period, reduced lesion numbers by 60%. The combined effects of reduced numbers of lesions and urediniospores per lesion caused by extreme temperature highs can account for observed absence or delay of soybean rust development in the southeastern United States until fall. A comparison of frequency of extreme temperature highs with numbers of counties reporting presence of soybean rust from 2005 to 2012 verified that extreme temperature highs may be largely responsible for absence or delay of soybean rust development. This is the first report showing the effect of frequency of extreme temperature highs on development of soybean rust. Because the south-to-north progression of soybean rust is required for the disease to occur in the major soybean-production regions of the United States, temperatures in the southeastern United States have a major effect on the entire U.S. soybean industry.

show abstract

Documentation of an Extended Latent Infection Period by Phakopsora pachyrhizi, the Soybean Rust Pathogen

Cited by 3 publications

References 24 publications

From Select Agent to an Established Pathogen: The Response to Phakopsora pachyrhizi (Soybean Rust) in North America

From Select Agent to an Established Pathogen: The Response to Phakopsora pachyrhizi (Soybean Rust) in North America

Development of a Quantitative Polymerase Chain Reaction Detection Protocol for Cercospora kikuchii in Soybean Leaves and Its Use for Documenting Latent Infection as Affected by Fungicide Applications

Effects of Frequency of “Extreme” Temperature Highs on Development of Soybean Rust

Contact Info

Product

Resources

About