September 15 2006
From: ProMED-mail <promed@promedmail.org>
Source: stopsoybeanrust.com [edited]
<http://www.stopsoybeanrust.com/viewStory.asp?StoryID=951>

Asian soybean rust has been confirmed for the 1st time in 2006 in North Carolina, in Columbus County on the border with South Carolina.
The find joins 2 more in Georgia and another in Louisiana since Tuesday.

This raises the number of states with rust this year to 8, in 54 counties and parishes. Last year at this time, there was rust in 58 counties in only 5 states: Alabama, Florida, Georgia, Mississippi and South Carolina. The additional states with rust at this point in 2006 are Louisiana, North Carolina and Texas.

Georgia also reported rust in Cook County today and in Sumter County on Tuesday, the same day Louisiana reported rust in commercial field in Washington Parish.

According to the N.C. state commentary on <http://www.sbrusa.net>, "Asiatic soybean rust was identified on soybean samples collected from a mobile sentinel plot on 13 Sep 2006. A few pustules were found on several leaves.

"The soybean leaves were collected from near Tabor City in Columbus County. Columbus County borders on South Carolina and is about 50 miles from Myrtle Beach, S.C.

The report from Steve Koenning and Jim Dunphy said 91 percent of the soybean crop in the state has set pods, "thus about 85 percent to 95 percent of the crop is no longer at risk.

"Soybean producers in the southern counties of North Carolina should be alert for rust moving any closer. If rust gets within 100 miles, and the soybeans do not yet have fairly good-sized seeds in the pods, we suggest spraying with a strobilurin fungicide. Assuming that some growers may not get into the field before mid-week after the rain, consider a combination of a strobilurin and a triazole (Headline SBR, Stratego, or Quilt) especially on late maturity (Group VII or VIII) and/or late-planted soybean.

"Soybeans that have full-sized soybeans in the pods (stage R6) before rust is identified in the field will probably mature before rust causes significant yield loss, and it is illegal to spray any of our fungicides that late in soybeans' development. As infrequently as rust affects soybeans that have not started blooming, we also would not spray soybeans that have not started blooming yet."

Georgia reports on <http://www.sbrusa.net> that "Soybean rust was reported 9/13 in an industry research plot in Sparks in Cook County Georgia. This is the first report of rust in that county this growing season. Cook County is located in south central Georgia, south of Tift County Georgia. Rust has already been confirmed in Tift County, so this report in Cook County is no surprise."

On 12 Sep 2006, soybean rust was detected on a soybean sample collected 18 Sep from one of the sentinel plots in Plains, GA (Sumter County, located in west Georgia). Rust was detected with a dissecting microscope on one leaflet of 100 collected, with fewer than 20 rust pustules on the leaf. This is the first find of rust in that county this growing season.

"With the recent rains and the numerous findings of rust in South Carolina, it is extremely important that everyone continue to scout their soybeans for possible rust and be prepared to spray if you have not done so already," the report said. "If you are a soybean grower in Georgia, please follow the management recommendations given by Dr.
Bob Kemerait given below:

"Spray guidance: It is likely that most of the commercial soybean crop in Georgia is now in the R4 (full pod stage) and may be moving to the R5 growth stage (early seed) where seeds are approximately 1/8 inch in length.

Theoretically, the soybean crop is at risk to Asian soybean rust until it reaches R6 (full seed) growth stage. Here are our recommendations:

"1. For growers whose crop is from R2 (full flower) to R4 (full pod), we recommend that a fungicide application is warranted for Asian soybean rust in all but the extreme northwest corner of the state (northwest Georgia should continue to monitor for rust). Growers whose crop is between R2 and R4 should use a triazole fungicide (such as Folicur, Domark, Laredo, Uppercut, etc.) or combination of triazole/strobilurin (such as Headline SBR) if infection has likely occurred in their field (e.g. SW Georgia and they have decent yield potential.

"Where it is unlikely that infection is established in a field, or that infection is very low, growers can effectively use any of our labeled products for control (strobilurins, triazoles, strobilurins & triazoles). Use of chlorothalonil must be considered carefully at this point. Our data suggests that chlorothalonil products do not perform as well as other products where disease infection may have already occurred.

"2. If the crop has reached the R5 growth stage in a field, the crop is still technically at-risk to soybean rust. However, given the slow spread of the disease until now, it seems unlikely that soybean rust will severely affect this crop before it reaches R6 (full seed). For growers who are concerned and wish maximum insurance, follow the spray recommendations above. However, we do not have a general spray recommendation for soybeans that have already reached the R5 stage and where rust is not yet found."

Louisiana reported on 12 Sep on <http://www.sbrusa.net> that "Asian soybean rust was found in Washington Parish in a commercial field of soybeans. Although this sighting is the first for the parish, the crop is in the late stages of development. No treatment is required."

[Byline: Marilyn Cummins]

--
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.

ASR is sufficiently widespread in the 8 states / 54 counties or parishes where it has been reported in 2006 that most state extension plant pathologists are recommending preventive spraying of fungicides for soybeans that are not yet mature. ProMED-mail does not endorse or recommend any of the specific fungicides mentioned in the report.
Most soybean crops in these states are beyond the stages singled out for spray treatment, minimizing the overall impact of ASR in 2006 despite its now widespread distribution. Most reports indicate that incidence/severity of ASR was low when found. It is noted in the report that on this date (mid September) in 2005 Louisiana, North Carolina and Texas had not yet reported ASR.

The posted report represents one of 30 similar reports that have been filed on the <http://www.sbrusa.net> web site since the last ProMED-mail update on 15 Aug 2006 (20060815.2288). These are summarized below, by date (most recent 1st), state, county or parish, nature of report, host plant and type of field/plot. Individual reports mostly resemble the one above and can be found at <http://www.stopsoybeanrust.com>.

Sept 14
Georgia - Cook : 1st county report 2006 soybean research North Carolina - Columbus : 1st state report 2006 soybean sentinel furthest north

Sept 12
Louisiana - Washington : 1st parish report 2006 soybean commercial Georgia - Sumter : 1st county report 2006 soybean sentinel

Sept 11
South Carolina - Anderson : 1st county report 2006 soybean sentinel South Carolina - Colleton : 1st county report 2006 soybean sentinel South Carolina - Dorchester : 1st county report 2006 soybean sentinel South Carolina - Horry : 1st county report 2006 soybean sentinel South Carolina - Lee : 1st county report 2006 soybean sentinel

Sept 8
Georgia - Burke : 1st county report 2006 soybean sentinel Louisiana - Catahoula : 1st parish report 2006 soybean commercial South Carolina - Calhoun : 1st county report 2006 soybean sentinel South Carolina - Hampton : 1st county report 2006 soybean sentinel South Carolina - Sumter set to Confirmed on 2006-09-08 : 1st county report 2006 soybean sentinel high severity

Sept 7
South Carolina - Florence : 1st county report 2006 soybean sentinel, furthest north/east Georgia - Grady : 1st since earlier eradication kudzu Georgia - Seminole : 1st county report 2006 soybean volunteer Georgia - Thomas : 1st since earlier eradication kudzu

Sept 6
Mississippi - Jackson : 1st county report 2006 soybean

Sept 5
Georgia - Colquitt : 1st county report 2006 soybean sentinel

Aug 31
South Carolina - Orangeburg : 1st county report 2006 soybean sentinel

Aug 27
Texas - Liberty : 1st county report 2006 soybean commercial

Aug 23
Louisiana - Concordia : 1st parish report 2006 soybean sentinel

Aug 21
South Carolina - Calhoun : 1st county report 2006 soybean sentinel, furthest north Alabama - Montgomery set to Confirmed,Destroyed on 2006-08-21

Aug 18
Lousiana - Iberia : 1st parish report 2006 soybean Lousiana - St Mary : 1st parish report 2006 soybean

Aug 15
Louisiana - Avoyelles : 1st parish report 2006 soybean Louisiana - Tensas : 1st parish report 2006 soybean

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

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 (10): USA 20060815.2288 Soybean rust, Asian strain update 2006 (09): USA 20060802.2143 Soybean rust, Asian strain Update 2006 (08): USA 20060711.1898 Soybean rust, Asian strain update 2006 (07): USA 20060703.1830 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
----
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]