CURRENT TEXAS SITUATION: August 13, 2008
Rust is currently present in Cameron County, in two soybean fields near Brownsville, in the Lower Rio Grande Valley and in Polk County, on kudzu in Livingston. No rust has been found in other areas of the state, including Liberty County, which received rain recently from both the hurricane and tropical storm.
Photos:- * Symptoms of downy mildew on a soybean leaf. This disease will not cause losses to soybeans in Texas
- * Symptoms of Asian soybean rust (red arrow) found on soybean from the Lower Rio Grande Valley of Texas. in 2007. Note extensive mite damage (white specks).
- * Symptoms of Asian soybean rust (red arrow) on soybean from the Lower Rio Grande Valley of Texas in 2007.
PROGNOSIS:
There will probably be an increase in rust incidence in the Lower Rio Grande Valley. Some fields there are younger than R4 and could be vulnerable to yield loss. Dry weather will greater hinder disease progression.
Most fields in the rest of the state are too mature to warrant fungicide applications. A small acreage in Liberty County may be at risk, should soybean rust appear there.
RECOMMENDATIONS:
Growers in the Lower Rio Grande Valley who have soybeans at R1 to R3 should apply a fungicide containing a triazole. These growers have the highest risk for disease loss.
Until rust is detected somewhere in the Upper Gulf Coast, I am not recommending fungicide applications in other areas of the state at this time.
Keep scouting. Send suspicious leaves to our lab for confirmation of rust.
CONTACTS FOR INFORMATION AND DIAGNOSIS:
Samples should be submitted for diagnosis to your local county agent or to Texas Plant Disease Diagnostic Laboratory, particularly if the plant is something other than soybean or kudzu.
TPDDL, 1500 Research Parkway, Suite A130
Texas A&M University Research Park
College Station, Texas USA 77845
Phone: (979) 845-8032 Fax: (979) 845-6499
SYMPTOMS More | Photo Archives
This is not soybean rust! It looks like it, except that it lacks the raised pustules that would be visible with magnification. It is probably a mineral deficiency. If you are unsure whether you have soybean rust, hold off spraying until you receive a diagnosis through our lab. With very dry conditions throughout much of the state, such rust-like symptoms may be common. This leaf was collected from Burleson County, June 8, 2008.
SENTINEL PLOTS AND SURVEYS:
Sentinel plots are located in soybean production areas throughout the state. Additionally, ad hoc surveys are made of commercial fields and kudzu patches. The map below shows the two locations of soybean rust found in Texas, on a kudzu patch in Livingston, in Polk County, and on soybeans near Brownsville, in Cameron County.
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