June 9, 2006
From: ProMED-mail<promed@promedmail.org>
Source: Planetsave.com [edited]
<http://planetsave.com/ps_mambo/index.php?option=com_content&task=view&id=7318&Itemid=69>


Brazilian government underestimated losses with rust

Losses due to soybean rust are now estimated to exceed earlier estimates. Embrapa points to farm damage of USD 2.7 billion due to soybean rust, a value which includes productivity losses and extra expenses with fungicides. The estimate of the Ministry of the Agriculture was for USD 2 billion in this harvest (2005/2006). In the
2004/2005 season, the damage was estimated to be USD 1.285 billion.

"This was the worst year for level of incidence of soybean rust in Brazil, with the most serious losses happening in Mato Grosso and in Minas Gerais," said Jose Tadashi Yorinori, a researcher at Embrapa Soy (Brazilian company of Agricultural Research). The Alert Service provided by Embrapa, which is maintained in partnership with the Ministry of Agriculture, identified 1419 rust foci in the whole country in the 2005/2006 harvest, compared to 459 foci in the
2004/2005 harvest.

He observed that the loss of seed was smaller because in many states the producers increased the number of applications of fungicides, which elevated the costs of farming. On average, the number of applications rose from 1.7 to 2.5 applications. In Mato Grosso, for instance, productivity fell from 60 to 38 bags per hectare as a result of the disease. Tadashi said that the damage in those farms was around USD 200 per hectare.

A crop-free period of 90 days between the end of one crop and the planting of the next crop is being proposed for Brazil. The rule is already adopted in Mato Grosso and in Goias.

According to Embrapa, since the appearance of the disease in Brazil in the 2001/2002 season, losses equaled 12.4 million tons of seed and USD 7.7 billion in income.

[Byline: Nelson Tembra]

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ProMED-mail
<promed@promedmail.org>

[The crop plant soybean (_Glycine max_) develops symptoms of the disease Asian soybean rust when infected by the fungus _Phakopsora pachyrhizi_, Asian strain. In addition to soybean, cowpeas, green beans and other edible legumes can 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.

The pathogen had been limited to the Eastern hemisphere until it was found in Hawaii in 1994. Currently, the distribution of _P.
pachyrhizi_ includes Africa, Asia, Australia, South America, the continental USA (since November 2004), and Hawaii. The rapid spread of _P. pachyrhizi_ and potential for severe yield losses makes this the most destructive foliar disease of soybean. Because this posting deals with ASR in Brazil, the items in the archive below are for reports of soybean rust in the Americas excluding the USA.

Asian soybean rust has been known to drastically reduce yields in Asia. In areas where the pathogen occurs commonly, yield losses up to 80 percent have been reported. Asian soybean rust was 1st detected in Brazil in 2001/2002, and its impact on production is newsworthy.

The article gives information on the impact of Asian soybean rust on soybeans in Brazil in the current (2005/2006) crop season. It also summarizes past losses. The 2005/2006 crop season appears to have been the most heavily impacted by ASR to date in Brazil. It is noted that high costs of fungicides, which did increase yields, contributed significantly to the overall economic losses associated with managing ASR. This information is of interest to USA soybean growers as they continue to evaluate the possible impact this pathogen will have on their own production were ASR to become epidemic. In Brazil, soybeans can have overlapping seasons, and so disease can carry from crop to crop from soybean to soybean. This is not the case in the USA. It is unlikely that a disease-free period will be suggested as a means to manage ASR in the USA, though is seems like a sensible approach in Brazil. A comparison of ASR in Brazil and the USA is provided in the 2nd item in "Links" below.

Maps:
Mato Grosso, Brazil
<http://www.tageo.com/index-e-br-v-02-d-m921672.htm > Minas Gerais, Brazil <http://www.tageo.com/index-e-br-v-01-d-m922420.htm>

Pictures:
<http://www.wbhm.org/pics/features/soybean-icon.jpg>

Links:
<http://www.nal.usda.gov/ref/soyrust.html>
<http://www.plantpath.iastate.edu/soybeanrust/node/52>
- Mod.JAD]

[see also in the archive:
Soybean rust, Asian strain update 2006 (02): USA 20060221.0568 Soybean rust - Mexico: 1st report 20060219.0546
2005
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Soybean rust, Asian strain - Uruguay 20050819.2435 Soybean rust - Argentina (Santa Fe)(02) 20050816.2397 Soybean rust, Asian strain - Argentina (Santa Fe) 20050617.1715 Soybean rust, Asian strain - Americas: alert 20050528.1476 Soybean rust, Asian strain - Argentina 20050119.0185
2004
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Soybean rust, Asian strain - Brazil 20041222.3374 Soybean rust, Asian strain - Brazil (multistate) 20041209.3266 Soybean rust, Asian strain - Brazil (PR) 20041129.3186 Soybean rust - Colombia (Cali) 20040827.2393
2003
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Phakopsora pachyrhizi, soybean - Brazil 20031119.2873 Soybean rust - Brazil 20030426.1022 Soybean rust - Brazil (Mato Grosso & Bahia) 20030415.0917 Soybean rust - Brazil (Sao Paulo State) 20030124.0214]