Asian soybean rust has been confirmed in several southern Alabama sentinel plots, according to Extension specialists with Auburn University.
“A graduate student found Asian soybean rust (June 28) in sentinel plots around Fairhope, Ala.,” said Ed Sikora, Extension plant pathologist with Auburn. “That's in Baldwin County, across the bay from Mobile.”
Rust was found on two plants with “roughly 10 leaves on each plant showing symptoms in the lower canopy — typical lesion formations. The samples were brought to Auburn. We confirmed the rust through several tests.”
There are two sentinel plots in the area — one late; one earlier. “One of the infected plants was found in the older sentinel plot where beans were at R-6. The other plant was found on the neighboring sentinel plot at R-1/R-2.
“We also have Syngenta spore traps — slides covered with petroleum jelly — in the area,” said Sikora. “On June 27, we found four spores that look like Asian rust in one of those traps.”
Sikora is advising producers in south and south-central Alabama to “strongly consider a tank-mix or a pre-mix of a triazole and strobilurin. We just don't know how far it's moved up.”
There's no indication rust has spread in neighboring Georgia. Rust was found on volunteer soybeans in the extreme southwest part of the state several months ago. Thus far, it seems to be staying put.
“Our scout team has spent yesterday and today scouting our sentinel plots,” said Phil Jost, Georgia Extension soybean specialist on June 30. “Until 3 p.m. today, we haven't found anything to worry about. The only soybean rust we've found remains in Seminole County on volunteer beans.”
In Mississippi, Alan Blaine, state Extension soybean specialist, said most of the state's crop is at a stage where “we normally spray a fungicide for things other than Asian soybean rust. The decision for producers is whether to spray a (triazole/strobilurin) as well. At this point, I don't think we have (Asian rust).”
Blaine's belief is bolstered by two factors: weather and scouting. “Consider where the rust was found in Alabama. They found it north of Gulf Shores on the coast — it rains there frequently. I can assure you we haven't had rain frequently in the soybean-growing areas of Mississippi. Based on that, I'm not going to change my plans for our test fields yet. Even if it is spreading, it doesn't appear there's a lot of inoculum out there.”