Soybean  rust found in Texas 

By MONETTE TAYLOR | South Central Texas Edition

Tom Isakeit, Extension plant pathologist, shows the rust pustules on the underside of a kudzu leaf. Tops of the leaves showing symptoms are in the background. Isakeit found evidence of  soybean rust on the plants in Liberty County. He used microscopic examination and ELISA testing to confirm the disease, but the leaves were also sent to the USDA laboratory in Maryland for final confirmation. � Extension photo�

Nov. 17, 2005 - Up until Nov. 2, the good news for Texas had been that the Asian soybean rust fungus, Phakopsora pachyrhizi, had not reached the state. But, according to Extension Plant Pathologist Tom Isakeit, luck has just run out.

In a report filed by Isakeit, soybean rust “… was confirmed on kudzu leaves that I collected Nov. 2, 2005 from a site near Dayton, Texas (Liberty County). The diagnosis was made by microscopic examination and ELISA testing. The ELISA test was done under the supervision of Dr. Larry Barnes at the Texas Plant Disease Diagnostic Laboratory in College Station.  Samples of the leaves will be sent to the USDA laboratory in Maryland for final confirmation.”

On Nov. 10, the soybean rust was confirmed by a U.S. Department of Agriculture laboratory in Beltsville, Md.

Isakeit noted that he had, also, surveyed kudzu near Livingston in Polk County, and Newton in Newton County, as well as soybeans at the Texas Agricultural Experiment Station in Beaumont. All were negative for the pathogen.

According to Isakeit, this is the first report of the disease in Texas, and follows the first report for 2005 in Louisiana by one week. As of Nov. 9, North Carolina was the state farthest east reporting soybean rust, and Louisiana was the furthest west … until final confirmation was made on the sample from Liberty County.

In 2005 the following states reported these numbers of counties with soybean rust:  Alabama - 29; Florida - 23; Georgia - 34; Mississippi - 2; South Carolina - 18; North Carolina - 14; Louisiana - 1 and, now, Texas-1.  The rust seems to move faster during the late summer and early fall, with the following numbers reported between August and November 2005:  August - 35; September - 10; October - 47; and as of Nov. 10, 14 counties reported new findings.

During an early presentation by Dr. Joe Krausz, Extension program leader for plant pathology, information relayed the soybean rust reached South America in 2001 and arrived in the United States in 2004, following Hurricane Ivan. Since the spores are airborne, they are able to spread through “urediospores that are released from an infected plant,” and can travel thousands of miles, contaminating hundreds of fields along the way.

Until this latest finding by Isakeit, soybean rust has been considered more of a threat for the midwestern states, since their weather conditions are more conducive to allowing development of the rust.

Fortunately, Isakeit explained, that because it is the end of the soybean season, he doesn’t expect economical damage for this year. With the cost of pesticides rising, he suggested monitoring infected plants to make sure they completely die off at the end of the season. He doesn’t believe anything needs to be done to the 2005 crops.

Although there is no real proof, it is thought that the latest infections could have been caused by the latest rash of hurricanes that affected Texas, Louisiana and other adjoining states, but there is no final word from experts, yet.

Isakeit noted that most of the soybean rust appears toward the bottom of plants where there is more shade and humidity, with older, higher leaves being less susceptible to the infection.

If producers suspect they may have soybean rust in their fields, they should notify their Extension agent or contact the Extension office in their county.  Isakeit said he is available to talk with producers at 979-862-1340. For more information, visit online at www.sbrusa.net/.