Florida soybean rust scouts report today that a sixth county has rust thriving in kudzu. So for no rust has been found on soybeans in the state, but was found in Georgia several weeks ago on volunteer soybeans - and those plants were destroyed.
Scouting continues throughout the eastern U.S. from the Gulf coast to southern Ontario and so far there have been no other finds. The Web site - www.sbrusa.net - reports that wet conditions have been right for rust formation, but hotter temperatures will be less favorable for spore production.
The site also notes that "if the winds and rain associated with tropical storm Arlene were involved in transporting soybean rust spores from known U.S. sources, and potentially other unknown sources in the U.S. and the Caribbean basin, new soybean rust infections could begin showing up in the next 5 to 10 days."
Florida Report - June 29, 2005
Asian soybean rust was first confirmed on kudzu in Dade Co. On June 15, it was found on kudzu in Jefferson county and again on kudzu in adjacent Leon county on June 27. There are now a total of six counties in FL with positive confirmations of soybean rust: Dade, Hernando, Pasco, Marion, Jefferson, and Leon. All confirmations are on kudzu.
Soybeans in FL are flowering and developing pods. Sentinel plots are at R3 or beyond with closed canopies. Kudzu vines are growing rapidly and closed canopies maintain high humidity and lower temperatures - an environment conducive to disease.
At present we still do not recommend the application of fungicides targeting Asian soybean rust. It has not yet been found on this season's soybeans. We recommend that you continue to monitor carefully. Recent information indicates that high rainfall (5-6 inches in 30 days) is required for a severe epidemic. Many parts of Florida, after a dry April, have now received that. With tropical storm Arlene and recent rains, things could change very quickly. Growers should have full knowledge of equipment required and what fungicides are available.
Commentary Not Available
Scout the oldest soybean plants available, looking for those that are flowering. Check the lower third of the canopy, especially in areas where canopy closure has occurred. Scout kudzu, especially in shaded areas or deep in the canopy. All 2005 positive finds in FL as of 6-29-05 have been on kudzu.