ASR on kudzu - Louisiana: 1st report 2006
Date: 30 Jun 2006
From: ProMED-mail <promed@promedmail.org>
Source: Stopsoybeanrust.com [edited]
<http://www.stopsoybeanrust.com/viewStory.asp?StoryID=870>

ALERT: Soybean rust found in kudzu near Lafayette, Louisiana.

Asian soybean rust was found today [30 Jun 2006] in a small patch of kudzu just south of Lafayette, Louisiana, in Lafayette Parish. This is the 23rd positive county in the USA and the 5th state to have rust this year [2006].

According to the Louisiana commentary on the USDA site and a release sent out by Clayton Hollier, plant pathologist with Louisiana State University, "agricultural consultant Blaine Viator found the infected leaves in a shady area in which dew probably was maintained. This may have provided ideal conditions for infection. This is the 1st report of ASR in Louisiana during 2006. No Asian soybean rust has been found on soybeans in the state this season.

This confirmation puts soybean rust in the state a full 4 months before it was found there in 2005. Soybean rust was not found in Lafayette Parish last year [2005]; the only 2 positive counties in Louisiana in 2005 were East Baton Rouge (on soybean 28 Oct 2005) and Tangipahoa (on kudzu 30 Nov 2005).

Don Hershman, University of Kentucky plant pathologist, commented that "finding rust in the state 4 months earlier than last year [2005] does not bode well."

"What does this really mean for the soybean industry? The presence of ASR in kudzu, with no sightings in soybeans, means that soybean fields need to be scouted at least every 2 to 3 days, especially in areas along tree lines that are shaded in the morning. These shaded areas maintain longer dew periods and can reduce temperatures enough to encourage ASR development if the spores are present.

"Growth stages at which flowers 1st appear through early pod filling (R1 through R5) are especially sensitive to potential yield losses if rust develops at that time. It is during these stages that fungicides should be applied if there is a threat of disease.

[Byline: Louisiana commentary on the USDA site plus Don Hershman listserv e-mail of Clayton Hollier's comments.]

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ProMED-mail
<promed@promedmail.org>

ASR on soybean - Alabama: 1st report 2006
Date: 30 Jun 2006
From: ProMED-mail <promed@promedmail.org>
Source: Stopsoybeanrust.com [edited]
<http://www.stopsoybeanrust.com/viewStory.asp?StoryID=868>

ALERT: Soybean rust found in AL soybean sentinel plot

Asian soybean rust has been confirmed in the Baldwin County soybean sentinel plot at Fairhope, Alabama.

According to the Alabama state commentary from 29 Jun 2006 on <http://www.sbrusa.net>, "soybean rust was confirmed on soybeans in Alabama yesterday. This is the 2nd report of soybean rust on soybeans in the United States in 2006."

[Stopsoybeanrust.com editor's note: while the 1st report on soybeans this growing season was in a Florida sentinel plot 15 Jun 2006, rust also was found on late-harvested 2005 soybeans in Texas in February 2006.]

"The disease was detected on leaves collected from the Baldwin County soybean sentinel plot in Fairhope on 27 Jun 2006. The leaves were incubated for 48 hours, and we observed the pustules and spores typical of this pathogen. A total of 5 soybean rust lesions were observed on 3 leaves. The disease was detected on Pioneer 93M90 (maturity group III) at the R5-R6 growth stage. The disease was not observed on a maturity group IV variety (Pioneer 94M80) at the R4 growth stage planted adjacent to the 93M90's. Leaves were also collected from 3 commercial soybean fields in Baldwin County, but no rust was observed. These fields ranged in development from V4-V6."

Don Hershman, University of Kentucky plant pathologist, notes that this find was made almost to the day when it was found in Baldwin County (Fairhope) last year [2005].

"One big difference, according to Ed Sikora, is that Fairhope is down 15 inches in rain compared to last year [2005], and the beans are very drought stressed," Hershman said. "This indicates to me that the soybean rust pathogen is able to infect (albeit not at high levels) even under very dry conditions. This find is significant in that I believe it signifies a shift in the soybean-rust situation for this year [2006]. I anticipate we will now begin to see an upturn in soybean rust. The main question now is how fast it moves and where. At this point, it is a race against time as far as the soybean crop goes. Most of our full season soybeans are nearing or are in the reproductive stages. Doublecrop soybean are considerably further behind in development," he said.

[Byline: Marilyn Cummins, Alabama and Georgia state commentaries on <http://www.sbrusa.net>; Don Hershman listserv e-mail]

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ProMED-mail
<promed@promedmail.org>

[Asian soybean rust (ASR) is a plant disease caused by the fungus _Phakopsora pachyrhizi_ and was introduced into the USA in 2004. In addition to the crop plant soybean (_Glycine max_), cowpeas, green beans, and other edible legumes could be affected by the ASR pathogen, which causes defoliation and yield reduction. Kudzu (_Pueraria lobata_, a.k.a. Japanese arrowroot) is an important alternate host for the pathogen in southern states of the USA.

New reports of ASR on kudzu in southern states of the USA have been made but not posted on ProMED-mail since the last posting in this series on 16 Jun 2006 (20060616.1667). In the 1st report in this posting, the detection of ASR on kudzu for the 1st time in Lafayette Parish, Louisiana (LA) is noted, with the additional point that this outbreak is 4 months sooner than it was found anywhere in LA on kudzu in 2005. There is yet to be a report on soybean in LA in 2006, but growers will use this information to plan spraying of soybean crops.

The 2nd report announces the 2nd detection of ASR on 2006 soybean plants in the USA, in this case in Alabama (AL) in one of the sentinel plots maintained in that state. The timing in that state is similar to 2005. The 1st report was in a Florida sentinel plot 15 Jun 2006. ASR has yet to be reported in a commercial crop planting in 2006. This report in AL will put adjacent states like Georgia on higher alert.

It is too soon to predict or compare disease progression in 2006 and 2005, but these reports probably signal the start of more reports of ASR in soybean in the USA in 2006, especially in fields where plants remain immature.

Maps:
Asian soybean rust outbreaks 2006
<http://www.sbrusa.net>

The wheat rust corridor
<http://ars.usda.gov/images/docs/9757_9951/puccini_path.gif>

Pictures:
<http://www.dtnsoybeanrustcenter.com/index.cfm?show=65&mid=60&page=ALL>

Diagnosis cards (broadband best):
<http://www.aphis.usda.gov/lpa/issues/sbr/SBR_IDcard_11-04.pdf>

Links:
<http://www.sbrusa.net>
National commentary, updates from states, maps, chronology.

<http://www.stopsoybeanrust.com/mc_home.asp>
Latest news, articles, maps and tracking information.

<http://www.dtnsoybeanrustcenter.com/index.cfm?show=10&mid=31>
Latest news, articles and other information.

<http://www.stopsoybeanrust.com/mc_resources.asp>
More links on ASR. - Mod JAD]

[see also in the archive:
Soybean rust, Asian strain update 2006 (06): USA 20060616.1667 Soybean rust, Asian strain update 2006 (05): USA 20060612.1642 Soybean rust, Asian strain update 2006 (04): USA 20060518.1402 Soybean rust, asian strain update 2006 (03): USA 20060226.0622 Soybean rust, Asian strain update 2006 (02): USA 20060221.0568 Soybean rust - Mexico: 1st report 20060219.0546 Soybean rust, Asian strain update 2006 20060214.0482 Soybean rust, Asian strain - USA (GA) 20060208.0415 ProMED-Plant Disease Report: July - December 2005 20060201.0331
2005
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Soybean rust, Asian strain - USA: 2005 disease summary 20051228.3694 Soybean rust, Asian strain - USA (KY)(02): confirmed 20051219.3640 Soybean rust, Asian strain - USA (multistate) (10) 20051218.3628 Soybean rust, Asian strain - USA (KY): 1st report 20051123.3404 Soybean rust, Asian strain - USA (multistate)(09) 20051101.3187 Soybean rust, Asian strain, kudzu control 20051006.2914 Soybean rust, Asian strain - USA (GA)(05) 20051005.2902 Soybean rust, Asian strain - USA (AL)(04) 20050917.2743 Soybean rust, Asian strain - USA (multistate)(08) 20050913.2711 Soybean rust, Asian strain - USA (multistate) (07) 20050909.2672 Soybean rust, Asian strain - USA (GA) (04) 20050905.2623 Soybean rust, Asian strain - USA (multistate)(04) 20050829.2556 Soybean rust, Asian strain - USA (GA)(03) 20050827.2531 Soybean rust, Asian strain - USA (AL)(03) 20050826.2528 Soybean rust, Asian strain - USA (AL)(02) 20050824.2496 Soybean rust, Asian strain - USA (SC) 20050818.2414 Soybean rust, Asian strain - USA (FL)(03) 20050815.2386 Soybean rust, Asian strain - USA (Multistate)(06) 20050808.2318 Soybean rust, Asian strain - USA (multistate)(05): susp. 20050806.2291 Soybean rust - USA (multistate)(04) 20050806.2289 Asian soybean rust, Asian strain - USA (multistate) 20050724.2133 Soybean rust, Asian strain - USA (AL) 20050715.2029 Soybean rust, Asian strain - USA (multistate)(03) 20050714.2005 Soybean rust, Asian strain - USA (multistate)(02): Florida 20050708.1938 Soybean rust, Asian strain - USA (multistate) 20050702.1868 Soybean rust, Asian strain - USA (LA) 20050624.1769 Soybean rust, Asian strain - USA (FL) (02) 20050620.1731 Soybean rust, Asian strain - USA (GA) 20050505.1245 Soybean rust, Asian strain - USA (GA) 20050429.1196 Soybean rust, Asian strain - USA (FL): 1st report 2005 20050309.0693]