SOYBEAN RUST FOUND IN ALABAMA FIELD
BALDWIN COUNTY-- After reporting soybean rust in sentinel plots in Baldwin County, Alabama, in late June, Alabama has now confirmed the first discovery of rust in commercially grown soybeans in that same county on July 12. Reportedly, the field is at the R4-R5 stage and had been treated with a fungicide two weeks prior to the find.
Auburn University extension plant pathologist Ed Sikora said the rust was confirmed in light severity and the number of spores was relatively low. To track the progress of this and other cases of Asian soybean rust as they are confirmed, visit USDA's Web site at www.usda.gov/soybeanrust.
This newest field with rust infestation is approximately one mile northeast of the soybean sentinel plots that were observed to have rust in late June. Sikora said the field is the only one in the area beyond bloom stage, and told Corn and Soybean Digest, "Many of our fields are still in the early vegetation stages, and I'm not suggesting any spraying until bloom. Most of the literature says fungicide applications prior to bloom are not economical."
That said, in his report on the USDA website, Sikora does advise that growers in southern and central Alabama with a crop between bloom (R1) and pod fill (R6) should consider applying a premix or tank mix of a strobilurin and triazole-type fungicide.
He adds that an application at the R3 growth stage, regardless if rust is reported in the immediate area, would provide about three weeks protection against rust as well as reduce damage from Cercospora blight and frogeye leaf spot.
Rust outlook still hinges on weather; scouting imperative
Given the announcement of rusts' spread in Alabama, plant pathologist Ed Sikora anticipates more confirmed cases in the next week. He says, "I think we will see more. The weather condition is ripe for it."
However, he reports that the level of rust spores for disease inoculum is still considerably low, which he says could mean less widespread movement. He adds, "If we're going to see symptoms, I think we'll see them in the next 5 to 7 days."
Of the mood of growers in his region, Sikora says, "Most growers in the state are aware there's a potential problem. They are concerned, and many have sprayed."